Hereditary Hyperferritinemia with Congenital Cataracts

Mendelian MONDO:0010952 Pathograph 21 Show in embeddings browser hereditary disease eye disorder inherited disorder of iron metabolism

Hereditary hyperferritinemia-cataract syndrome (HHCS) is an autosomal dominant disorder caused by non-coding point mutations or small deletions in the iron-responsive element (IRE) in the 5' untranslated region of FTL. The IRE is the stem-loop that iron-regulatory proteins IRP1 and IRP2 occupy when cellular iron is low, blocking assembly of the translation preinitiation complex on L-ferritin mRNA. Variants that distort the hairpin lower or abolish IRP affinity, so L-ferritin translation runs constitutively and is no longer coupled to iron supply. The result is a very high serum ferritin with a normal serum iron and a normal transferrin saturation, and no parenchymal iron loading, together with bilateral early-onset cataract produced by crystalline L-ferritin deposits in lens fibre cells. Clinically the disorder is benign apart from the lens, and its main hazard is iatrogenic: because serum ferritin is routinely read as a surrogate for body iron stores, HHCS is repeatedly mistaken for hereditary haemochromatosis and treated with venesection or iron chelation, which cannot lower a genetically driven ferritin and instead produces iron deficiency. This entry is mechanistically distinct from `kb/disorders/neuroferritinopathy.yaml`, which is caused by FTL coding-region variants and features brain iron accumulation with low-to-normal serum ferritin.

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1
Inheritance
8
Pathophys.
6
Phenotypes
2
Gaps
21
Pathograph
1
Genes
4
Variants
3
Medical Actions
3
Differentials
22
References
2
Deep Research
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Classifications

Harrison's Part
ONCOLOGY HEMATOLOGY GENETICS ENVIRONMENT DISEASE
ICIMD (Inherited Metabolic Disorders)
iron metabolism
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Inheritance

1
Autosomal dominant inheritance HP:0000006
Heterozygous FTL IRE variants segregate with both the hyperferritinaemia and the cataract through multiple generations. A negative family history does not exclude the diagnosis, because de novo variants occur. Rare homozygous individuals have been reported, and in at least one consanguineous family the homozygote had a markedly higher serum ferritin and the most severe cataract, indicating an allele-dose effect rather than a distinct recessive disease.
Autosomal dominant inheritance
Show evidence (3 references)
PMID:7492760 SUPPORT Human Clinical
"clinically characterized by the combination of elevated serum ferritin and congenital bilateral nuclear cataract, both cotransmitted as an autosomal dominant trait"
The original clinical description establishes co-transmission of both features as a dominant trait.
PMID:33221470 SUPPORT Human Clinical
"Lack of family history does not exclude HHCS, because the pathogenic variant can arise de novo."
Documents a paternity-confirmed de novo variant, so absence of an affected parent does not rule the diagnosis out.
PMID:29269865 SUPPORT Human Clinical
"The zygosity of the mutation, occurring in homozygous and heterozygous state in the proband and other affected family members respectively, correlated well with severity of ophthalmological and hematological manifestations."
Supports an allele-dose effect in the rare homozygous state within an otherwise dominant disorder.
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Discussions and Knowledge Gaps

2
Why is the lens the only tissue damaged by an L-ferritin excess that is present in every cell of the body?
KNOWLEDGE GAP hhcs_lens_tissue_selectivity
The derepression is constitutive and ubiquitous - lymphoblastoid cells from patients carry up to twenty-fold excess L-ferritin - yet the only organ that is injured is the lens. Three partial explanations are on the table and none has been tested against the others. FTL transcription is measurably higher in the lens than in neighbouring ocular tissue, so the same fractional derepression yields a larger absolute burden there. Lens fibre cells are post-mitotic, organelle-free and cannot dilute or degrade an accumulating protein, so a small chronic surplus integrates over decades. And Levi and colleagues proposed that L-ferritin specifically perturbs the solubility equilibrium of the crystallins or the lens antioxidant defences, which would make the injury a property of the lens proteome rather than of dose or kinetics. Distinguishing these matters practically, because only the third predicts that the crystallins are involved, and the entry's conformance to `cataract_lens_opacification` is deliberately declared around, not through, that module's crystallin-aggregation node for exactly this reason.
Show evidence (3 references)
PMID:29269865 SUPPORT Other
"Although ferritin accumulates in all cell types of HHCS patients, it turns out to be toxic only in the crystallin-containing lens fiber cells."
States the puzzle this gap is about - ubiquitous accumulation, single-organ injury.
PMID:29269865 SUPPORT Other
"Interestingly, it has been demonstrated that endogenous FTL transcription is significantly higher in the lens compared to other eye tissues, which is likely to contribute to the pathogenic levels of FTL deposits found in HHCS lenses"
The dose-based candidate explanation, offered by its own source as a likely contribution rather than a demonstrated cause.
PMID:9596665 SUPPORT In Vitro
"L-chain accumulation occurs also in the lens, where it may induce cataract formation by altering the delicate equilibrium between other water-soluble proteins (ie, crystallins) and/or the antioxidant properties."
The competing proteome-based explanation, likewise stated by its authors as a possibility.
Does IRE position predict phenotype severity well enough to be clinically useful, given how much variation there is between people carrying the same allele?
KNOWLEDGE GAP hhcs_genotype_severity_relationship
Two well-supported statements sit uneasily together. At the level of the allele, position in the IRE tracks severity: variants in the conserved apical hexanucleotide or the cytosine bulge give the highest ferritin values and the earliest, densest cataracts, while lower-stem variants can be nearly asymptomatic, and thermodynamic analysis correlates clinical severity with the extent of IRE-IRP disturbance. At the level of the patient, that signal largely disappears: the age at cataract diagnosis among sixteen carriers of a single allele spanned 6 to 40 years, ferritin values within one allele spanned 700 to 2,412 microgram/L, and the largest clinical series found no clear relationship between genotype and clinical severity at all. Whether the residual variance is modifier genes, environmental exposure of the lens, or simply measurement noise in a small and heavily ascertained corpus is not known, and until it is, an IRE position cannot be used to counsel an individual family about when their child will need surgery.
Show evidence (3 references)
PMID:20511138 SUPPORT Human Clinical
"Cazzola and co-workers showed that mutations in the highly conserved hexanucleotide region (eg at position 40 or 41) caused a severe cataract, while mutations around the bulge with unpaired cytidine (eg position 32) caused mild cataract."
The allele-level position-severity relationship that makes the gap worth stating.
PMID:15280904 REFUTE Human Clinical
"The severity of the clinical phenotype of HHCS was variable both within and between kindreds and showed no clear relationship to FTL genotype."
The largest clinical series found no usable genotype-phenotype relationship, which is the observation that contradicts the allele-level claim above and is why this is recorded as an open question rather than a settled one.
PMID:11703332 SUPPORT Human Clinical
"Similarly, serum ferritin levels varied substantially also within subjects sharing the same mutation (i.e. range for the A40G: 700-2412 microg/l)."
Quantifies the within-allele spread in ferritin quoted in the rationale.
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Pathophysiology

8
FTL Iron-Responsive Element Disruption
Mechanism confidence: Established
The initiating lesion is a heterozygous single-nucleotide substitution or short deletion inside the ~30-nucleotide IRE hairpin encoded in the FTL 5' untranslated region. The IRE has four structural parts that matter: a conserved CAGUGN apical hexanucleotide loop, an upper stem, an unpaired cytosine bulge separating the stems, and a lower stem. Pathogenic changes cluster in the loop, the bulge and the upper stem, and act by distorting or destabilising the hairpin so that it no longer presents the surface that iron-regulatory proteins recognise. The FTL coding sequence is untouched, so the L-ferritin protein produced is structurally normal - which is what separates this disorder from the coding-region FTL diseases.
FTL hgnc:3999 HUGO Gene Nomenclature Committee (hgnc) Relation: this pathophysiological event involves this gene This pathophysiological event involves FTL (hgnc:3999). hgnc:3999 is a gene from the HUGO Gene Nomenclature Committee.
Genetic context variant_origin: GERMLINE zygosity: HETEROZYGOUS
Constitutional non-coding variant in the FTL 5' UTR. Almost all reported patients are heterozygous; a handful of homozygous individuals have been described in consanguineous families. Deliberately no functional_impact_category is asserted here: the enum describes the activity of a gene product, and this variant does not change the product at all, only the amount of it that is made. The variant-level claim is carried instead by `regulatory_category` on the entries in `genetic`.
Show evidence (3 references)
PMID:7492760 SUPPORT Human Clinical
"This mutation involves the five nucleotides sequence [CAGUG] of the iron-responsive element (IRE), which is critical for the posttranscriptional regulation of ferritin synthesis by means of IRE-binding protein (IRE-BP)."
Identifies the conserved apical loop of the FTL IRE as the site of the founding mutation and states its regulatory role.
PMID:20511138 SUPPORT Human Clinical
"The most important sequences are a highly conserved hexanucleotide at the terminal loop, a bulge with an unpaired cytidin, and the upper stem of the hairpin"
A survey of all mutations then reported localises the pathogenic changes to the loop, bulge and upper stem, which is the basis for the structural claim in this node.
PMID:20511138 SUPPORT Human Clinical
"Twenty-seven of these mutations are single nucleotide transitions and four are deletions of 2-29 base pairs."
Establishes that the allelic spectrum is substitutions plus short deletions, not coding changes.
Loss of Iron-Regulatory Protein Binding to the FTL IRE
Mechanism confidence: Established
In health, when cytosolic iron is low, IRP1 (in its apo, non-cluster form) and IRP2 bind the FTL IRE with high affinity and prevent recruitment of the small ribosomal subunit, so L-ferritin is not made. HHCS variants reduce that affinity. The reduction is graded rather than all-or-none: gel-shift assays across the allelic series show a spectrum from near-complete abolition to a partial, several-fold loss of affinity, and even a partial loss is enough to cause disease. This graded biochemistry is the mechanistic substrate for the clinical observation that different IRE positions give different disease severities.
iron-responsive element binding by IRP1 and IRP2 GO:0030350 Gene Ontology (GO) Relation: this pathophysiological event involves this molecular function This pathophysiological event involves decreased iron-responsive element binding by IRP1 and IRP2, annotated with iron-responsive element binding (GO:0030350). GO:0030350 is a molecular function from the Gene Ontology. ↓ DECREASED
Show evidence (3 references)
PMID:20511138 SUPPORT Other
"Under conditions of intracellular iron depletion, both IRPs can bind IRE with high affinity, prevent binding of the translation initiation complex and thus block ferritin translation"
States the normal repressive function this node reports the loss of. Graded OTHER because the source is a review summarising the physiology rather than reporting a study.
PMID:9226182 SUPPORT In Vitro
"Using a gel retardation assay, the observed molecular lesions were shown to variably reduce the IRE affinity for an iron regulatory protein (IRP), which inhibits ferritin mRNA translation."
Demonstrates directly, and across more than one allele, that the lesions reduce IRE-IRP affinity, and that the reduction is variable.
PMID:29269865 SUPPORT In Vitro
"the WT IRE has an KDapp of 0.50 nM, while the +49A > G mutant IRE demonstrates a more than 5-fold lower affinity for IRP1, with an KDapp of 2.70 nM"
Quantifies the affinity loss for one allele and shows it is partial, supporting the graded rather than all-or-none reading of this step.
Constitutive Derepression of L-Ferritin Translation
Mechanism confidence: Established
Translation initiation on FTL mRNA becomes constitutive. This is the qualitative change that defines the disorder: the process is not simply running faster, it has been removed from the regulatory circuit that normally couples it to cytosolic iron, so neither iron loading nor iron chelation of the cell moves it. HHCS is the founding example of what has been called translational pathophysiology - disease caused by a mutation that changes how efficiently an mRNA is translated rather than what it encodes.
iron-independent initiation of L-ferritin mRNA translation GO:0006413 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves iron-independent initiation of L-ferritin mRNA translation, annotated with translational initiation (GO:0006413), qualified as gain of function. GO:0006413 is a biological process from the Gene Ontology. ⇑ GAIN OF FUNCTION IRP-mediated translational repression of FTL mRNA GO:0045947 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves IRP-mediated translational repression of FTL mRNA, annotated with negative regulation of translational initiation (GO:0045947), qualified as loss of function. GO:0045947 is a biological process from the Gene Ontology. ⇓ LOSS OF FUNCTION
Show evidence (2 references)
PMID:10828006 SUPPORT Other
"Hereditary hyperferritinemia/cataract syndrome arises from various point mutations or deletions within a protein-binding sequence in the 5'-UTR of the L-ferritin mRNA. Each unique mutation confers a characteristic degree of hyperferritinemia and severity of cataract in affected individuals."
Frames HHCS as a translational-control disease and states the allele-specific dose relationship. Graded OTHER because this is a conceptual review rather than a primary study.
PMID:9596665 SUPPORT In Vitro
"Enzyme-linked immunosorbent assays specific for the H- and L-type ferritins showed that L-ferritin levels were up to 20-fold higher in HHCS than in control cells and were not affected by iron supplementation or chelation."
The unresponsiveness to both iron loading and chelation is the direct demonstration that translation has left the regulatory circuit, which is why this node is graded qualitatively rather than as a simple increase.
L-Ferritin Overproduction and Intracellular Accumulation
Mechanism confidence: Established
Cells accumulate five- to twenty-fold excess L-ferritin. Because the excess is of one subunit only, the assembled product is abnormal in composition rather than in structure: roughly half of the surplus L-chain assembles into L-chain-only 24-mer homopolymers, which lack the H-subunit ferroxidase centre and therefore do not take up iron at all, and the remainder shifts the normal heteropolymer population towards L-rich isoferritins. This is the reason the disorder does not cause iron overload despite an enormous ferritin burden - the extra shells are essentially empty.
L-chain-rich and L-chain-only ferritin shells GO:0070288 Gene Ontology (GO) Relation: this pathophysiological event involves this cellular component This pathophysiological event involves increased L-chain-rich and L-chain-only ferritin shells, annotated with ferritin complex (GO:0070288). GO:0070288 is a cellular component from the Gene Ontology.
Show evidence (3 references)
PMID:9596665 SUPPORT In Vitro
"in HHCS cells a large proportion of L-ferritin accumulates as nonfunctional L-chain 24 homopolymers"
Establishes the L-chain homopolymer species that carries the excess.
PMID:9596665 SUPPORT In Vitro
"the concomitant fivefold to 10-fold expansion of ferritin heteropolymers, with a shift to L-chain-rich isoferritins, does not have major effects on cellular iron metabolism"
Supports both the compositional shift and the crucial negative claim that cellular iron handling is left intact.
PMID:36768886 SUPPORT Other
"leading to constitutive up-regulation of L-ferritin, intracellular accumulation of ferritin, mainly in the form of the homopolymers H0-L24, and hyperferritinemia"
A recent review states the same subunit composition and links it forward to the hyperferritinaemia. Graded OTHER because it is a review synthesis.
Serum Hyperferritinemia Uncoupled from Body Iron Stores
Mechanism confidence: Established
Serum ferritin is persistently and often markedly elevated, commonly in the several-hundred to greater-than-2,000 microgram/L range, while serum iron, transferrin saturation, total iron-binding capacity and parenchymal iron content stay normal. The clinically decisive point is negative: this is not iron overload. Serum ferritin has simply stopped being an index of body iron in these patients, in both directions - it will also fail to fall when they become genuinely iron deficient.
Show evidence (3 references)
PMID:7492760 SUPPORT Human Clinical
"Differently from subjects with hereditary hemochromatosis, they have normal to low levels of serum iron and percent of transferrin saturation and absence of iron overload in parenchymal organs."
States the dissociation between the ferritin level and every other index of body iron.
PMID:41769540 SUPPORT Human Clinical
"While typically elevated in hereditary hemochromatosis, transferrin saturation remains normal in HHCS, reflecting preserved systemic iron homeostasis"
Names transferrin saturation as the discriminating measurement and states that systemic iron homeostasis is preserved.
PMID:36768886 SUPPORT Other
"In patients with HHCS, serum ferritin is no longer a reliable indicator of iron stores in both iron deficiency and iron overload, which is something to keep in mind."
Supports the bidirectional statement in this node's description, including the under-recognised risk of missing true iron deficiency.
Lens Fibre Cell L-Ferritin Accumulation
Mechanism confidence: Established
Lens fibre cells accumulate L-ferritin far in excess of any other tissue examined. Measured lens L-ferritin content in HHCS ranges from about ten-fold the control value in one extracted nucleus to roughly 1500-fold in two others, the spread reflecting different assays, cataract morphologies and ages at surgery. Two features of the lens plausibly explain why this is the one tissue that suffers: FTL transcription is unusually high there, and lens fibre cells are post-mitotic, organelle-free and protein-packed, with no way to dilute or turn over an accumulating protein. The tissue selectivity is nonetheless not formally resolved - see the knowledge gap recorded in `discussions`.
lens fibre cell CL:0011004 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves lens fibre cell, annotated with lens fiber cell (CL:0011004). CL:0011004 is a cell type from the Cell Ontology.
lens of the eye UBERON:0000965 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in lens of the eye, annotated with lens of camera-type eye (UBERON:0000965). UBERON:0000965 is an anatomical location from the Uberon multi-species anatomy ontology.
Show evidence (3 references)
PMID:9596665 SUPPORT In Vitro
"In addition, we analyzed the lens recovered from cataract surgery of a HHCS patient. We found it to contain about 10-fold more L-ferritin than control lens."
Direct measurement of L-ferritin excess in an HHCS lens.
PMID:11703332 SUPPORT Human Clinical
"The lens ferritin content was analysed in two subjects who underwent cataract surgery at different ages, with different cataract morphology. Values were similar and about 1500-fold higher than in controls."
A second, much larger measurement in two further lenses, and the source of the upper end of the range quoted here.
PMID:29269865 SUPPORT Other
"Although ferritin accumulates in all cell types of HHCS patients, it turns out to be toxic only in the crystallin-containing lens fiber cells."
States the tissue selectivity that makes this a distinct node rather than a restatement of the systemic overproduction.
Crystalline L-Ferritin Deposition and Lens Light Scattering
Mechanism confidence: Established
The excess L-ferritin comes out of solution as discrete crystalline inclusions within the lens substance. Immunohistochemistry on an extracted HHCS lens stains these inclusions for L-ferritin and not for H-ferritin, so they are made of the overproduced subunit itself. Refractive-index discontinuities at the inclusions scatter incident light and degrade the image reaching the retina. Levi and colleagues additionally proposed that the L-chain excess perturbs the solubility equilibrium among the crystallins, or the lens antioxidant balance, as a contributing mechanism; that proposal has not been tested directly and is recorded here as a hypothesis rather than as the established route.
lens fibre cell CL:0011004 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves lens fibre cell, annotated with lens fiber cell (CL:0011004). CL:0011004 is a cell type from the Cell Ontology.
Show evidence (4 references)
PMID:10873976 SUPPORT Human Clinical
"The cataract comprised discrete crystalline inclusions with positive staining with anti-L-ferritin but not anti-H-ferritin."
Establishes both the crystalline morphology of the deposits and their L-ferritin composition.
PMID:10873976 SUPPORT Human Clinical
"The HHCS lens L-ferritin content was 147 microg/g dry weight of lens compared with <16 microg/g for a non-HHCS control cataract lens."
Quantifies the lens burden against a cataractous non-HHCS control, so the excess is not simply a feature of any cataract.
PMID:36768886 SUPPORT Other
"Lens opacity probably results from overproduction of L-type ferritin, as shown by the presence of light-diffracting crystalline deposits rich in L-ferritin in cataractous lenses from individuals with HHCS"
States the optical step - light diffraction by the deposits - that this node asserts. Graded OTHER because it is a review synthesis.
+ 1 more reference
Iatrogenic Iron Depletion from Misdirected Venesection and Chelation
Mechanism confidence: Established
The commonest complication of HHCS is not caused by the disease. Because the ferritin elevation is generated by translation and not by stored iron, removing iron cannot correct it; what venesection does instead is strip a normal iron store from a patient who had one, producing iron deficiency and microcytic anaemia while the ferritin stays high. Iron chelation carries its own hazard: one 8.5-year-old treated with deferasirox on a mistaken diagnosis of iron overload developed life-threatening acute hyperammonaemia. Repeated liver biopsy for the same misdiagnosis is a further avoidable harm. This node is included in the pathograph because the harm is mechanistically predictable from the upstream biology, not because it is a property of the genotype.
Show evidence (4 references)
PMID:7492760 SUPPORT Human Clinical
"When unnecessary phlebotomies are performed, they rapidly develop iron-deficient anemia, with persistently elevated levels of serum ferritin."
The original description already recorded both halves of the harm - the induced anaemia and the failure of the ferritin to fall.
PMID:33221470 SUPPORT Human Clinical
"One individual, aged 43 years, underwent phlebotomy; another, aged 8.5 years, was treated with the iron chelator deferasirox, leading to life-threatening acute hyperammonemia, without severe liver injury."
Documents the chelation arm of the harm and its severity in a specific patient.
PMID:41769540 SUPPORT Human Clinical
"This intervention did not result in any clinically meaningful reduction in serum ferritin levels, supporting the absence of true iron overload."
An observed instance of the futility of venesection in HHCS, which is the mechanistic point of this node.
+ 1 more reference
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Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Hereditary Hyperferritinemia with Congenital Cataracts Interactive directed graph showing how pathophysiology mechanisms, phenotypes, genetic factors and variants, experimental models, environmental triggers, and treatments relate through causal and linked edges.
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Phenotypes

6
Blood 1
Iron Deficiency Anemia OCCASIONAL HP:0001891 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Iron deficiency anemia following inappropriate venesection, annotated with Iron deficiency anemia (HP:0001891). HP:0001891 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:20511138 SUPPORT Human Clinical
"These patients had been initially misdiagnosed with hereditary haemochromatosis, although no iron overload had been found in liver biopsies and they developed iron-deficiency anaemia after repeated venesections."
Records iron-deficiency anaemia as an observed consequence of venesection in misdiagnosed HHCS patients.
PMID:34064225 SUPPORT Human Clinical
"The proband and his daughter were treated as hereditary hemochromatosis with phlebotomies until they developed microcytic anemia."
A named instance of the same harm, and the source of the microcytic descriptor used in this phenotype's description.
Eye 4
Bilateral Early-Onset Cataract VERY_FREQUENT Developmental cataract HP:0000519 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Bilateral early-onset cataract, annotated with Developmental cataract (HP:0000519), qualified as laterality bilateral; course progressive. HP:0000519 is a phenotype from the Human Phenotype Ontology.
Laterality: BILATERAL Course: PROGRESSIVE
Sequelae: Visual Impairment
Show evidence (7 references)
PMID:41300832 SUPPORT Human Clinical
"Clinically, aside from isolated hyperferritinemia, the hallmark manifestation is progressive, bilateral cataract formation, usually developing in childhood or adolescence and often requiring surgical intervention"
Supports the bilaterality, the early onset, the progressive course and the frequent need for surgery.
PMID:15280904 SUPPORT Human Clinical
"We report the clinical features of seven HHCS kindreds containing 49 individuals with premature cataract."
The largest reported clinical series, establishing premature cataract as the constant clinical feature across kindreds.
PMID:11703332 SUPPORT Human Clinical
"A marked phenotypic variability was observed, particularly with regard to ocular involvement (i.e. age range at which cataract was diagnosed in 16 subjects with the C39T: 6-40 years)."
Quantifies the within-allele variability in age at diagnosis stated in this description.
+ 4 more references
Nuclear Cataract FREQUENT HP:0100018 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Nuclear cataract (HP:0100018). HP:0100018 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:7492760 SUPPORT Human Clinical
"clinically characterized by the combination of elevated serum ferritin and congenital bilateral nuclear cataract, both cotransmitted as an autosomal dominant trait"
Nuclear morphology is part of the founding clinical definition of the syndrome.
PMID:36768886 SUPPORT Other
"Apart from hyperferritinemia, the only consistent abnormality in affected patients is a nuclear cataract, which appears in infancy or before the age of 50 years"
A recent review calls nuclear cataract the one consistent abnormality, which is the basis for recording it separately from the general cataract phenotype.
Pulverulent Lens Opacities FREQUENT Pulverulent cataract HP:0010693 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Pulverulent, breadcrumb-like punctate lens opacities, annotated with Pulverulent cataract (HP:0010693). HP:0010693 is a phenotype from the Human Phenotype Ontology.
Lachlan and colleagues describe the morphology in their seven British kindreds as "sunflower" cataract, and HPO has a Sunflower cataract term (HP:6000642). It is deliberately not bound here: HPO defines that term as an anterior subcapsular copper deposit "almost only seen in Wilson disease", which is a different lesion in a different lens layer that merely shares a floral metaphor. Binding it would assert a Wilson-disease finding in an iron disorder. Pulverulent cataract, defined in HPO as punctate dust-like opacities of the fetal nucleus, matches the described lesion.
Show evidence (3 references)
PMID:20511138 SUPPORT Human Clinical
"The cataract develops due to L-ferritin deposits in the lens and its pulverulent aspect is pathognomonic."
States both the pulverulent morphology and its diagnostic weight, which is why this phenotype is flagged diagnostic.
PMID:20511138 SUPPORT Human Clinical
"The primary characteristics are the appearance of axial and peripheral white flecks and small crystalline aggregates."
Describes the axial and peripheral flecks and crystalline aggregates recorded in this phenotype's description.
PMID:15280904 SUPPORT Human Clinical
"All the probands developed characteristic 'sunflower' morphology cataracts in childhood (median age at diagnosis 5 years), but had no other phenotypic features."
Source of the radial sunflower-like description and of the median age at diagnosis of five years; see this phenotype's notes for why the HPO Sunflower cataract term is not used.
Visual Impairment FREQUENT HP:0000505 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Visual impairment (HP:0000505). HP:0000505 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:11703332 SUPPORT Human Clinical
"No relevant symptoms other than visual impairment were found to be associated with the syndrome."
A 62-patient series establishing visual impairment as the only symptom, which supports both the phenotype and the negative claim about the rest of the body.
Metabolism 1
Persistent Hyperferritinemia OBLIGATE Increased circulating ferritin concentration HP:0003281 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Increased circulating ferritin concentration (HP:0003281), qualified as temporality chronic. HP:0003281 is a phenotype from the Human Phenotype Ontology.
Temporal: CHRONIC
Show evidence (2 references)
PMID:7492760 SUPPORT Human Clinical
"In affected subjects, hyperferritinemia (ranging from 950 to 2,259 micrograms/L) is typically not related to iron overload."
Gives the observed concentration range in the founding family and states that it is not iron-related.
PMID:15280904 SUPPORT Human Clinical
"All the probands received diagnoses of HHCS after the incidental discovery of increased serum L-ferritin concentration (median 1420 microg/l; normal range 15-360 microg/l), in most cases during investigation or screening for anaemia."
Supplies the median value and the local reference interval quoted in this description, and documents the incidental route to diagnosis.
🧬

Genetic Associations

1
FTL
Gene: FTL hgnc:3999 HUGO Gene Nomenclature Committee (hgnc) Relation: this disease-associated gene is this gene This disease-associated gene is FTL (hgnc:3999). hgnc:3999 is a gene from the HUGO Gene Nomenclature Committee. relationship_type: CAUSATIVE
Show evidence (3 references)
PMID:34064225 SUPPORT Human Clinical
"At least 47 mutations have been described in FTL gene as causative of HHCS, including 36 single mutations, 9 deletions, and 2 insertion-deletions"
States the size and composition of the allelic spectrum in the single causative gene.
PMID:34064225 SUPPORT Other
"c.-160A>G is the same as the +40A>G Paris-1 mutation"
Documents the equivalence of the two numbering conventions described in these notes.
PMID:33221470 SUPPORT Human Clinical
"Noncoding regions are often omitted from diagnostic gene panels, thus evading detection."
Supports the diagnostic-ascertainment point made in these notes.
Variants (4)
FTL c.-168G>C Pathogenic
Gene: FTL hgnc:3999 HUGO Gene Nomenclature Committee (hgnc) Relation: this variant is in this gene This variant is in FTL (hgnc:3999). hgnc:3999 is a gene from the HUGO Gene Nomenclature Committee. GOE
A recurrent allele affecting the conserved three-nucleotide bulge of the FTL IRE, reported in Czech and Italian families among others.
Show evidence (2 references)
PMID:29426274 SUPPORT Human Clinical
"This report documents a second Italian family, with a c.-168G>C mutation that is located in the highly conserved 3-nucleotide bulge structure of the FTL in the 5' untranslated region."
Names the variant and localises it within the IRE bulge.
PMID:41300832 SUPPORT Human Clinical
"Genetic testing confirmed a heterozygous FTL c.-168G>C variant."
An independent family carrying the same allele, supporting its recurrence.
FTL c.-167C>T Pathogenic
Gene: FTL hgnc:3999 HUGO Gene Nomenclature Committee (hgnc) Relation: this variant is in this gene This variant is in FTL (hgnc:3999). hgnc:3999 is a gene from the HUGO Gene Nomenclature Committee. GOE
Documented arising de novo, with paternity confirmed - the allele that shows a negative family history cannot exclude the diagnosis.
Show evidence (1 reference)
PMID:33221470 SUPPORT Human Clinical
"but c.-167C>T occurred de novo (confirmed by paternity testing)"
Establishes de novo occurrence of this specific allele with paternity testing.
FTL c.-151A>G (Ghent +49A>G) Pathogenic
Gene: FTL hgnc:3999 HUGO Gene Nomenclature Committee (hgnc) Relation: this variant is in this gene This variant is in FTL (hgnc:3999). hgnc:3999 is a gene from the HUGO Gene Nomenclature Committee. GOE
An upper-stem allele just above the cytosine bulge. Predicted to disrupt base pairing at the base of the upper stem and, through that, the apical loop and the bulge. Notable as the best-quantified example of a partial lesion: it reduces IRP1 affinity more than five-fold without abolishing binding, and still causes disease. Reported homozygous in a consanguineous family, where the homozygote was the most severely affected member.
Show evidence (1 reference)
PMID:29269865 SUPPORT In Vitro
"The direct as well as competitive EMSA experiments show that +49A > G reduces, but not completely abolishes, the binding with recombinant IRP1."
The functional result behind the partial-lesion description of this allele.
FTL IRE six-nucleotide deletion (Italian family) Pathogenic
Gene: FTL hgnc:3999 HUGO Gene Nomenclature Committee (hgnc) Relation: this variant is in this gene This variant is in FTL (hgnc:3999). hgnc:3999 is a gene from the HUGO Gene Nomenclature Committee. GOE
An example of the deletion class of HHCS alleles, in a repeat-containing stretch such that the deletion can be written four equivalent ways. Cited here to make the point that the allelic spectrum is not confined to substitutions.
Show evidence (2 references)
PMID:11849230 SUPPORT Human Clinical
"We report a novel six-nucleotide deletion identified in an Italian family presenting with elevated serum ferritin and early onset bilateral cataract."
Documents a deletion allele and the phenotype it produced.
PMID:11849230 SUPPORT Computational
"Structural modelling predicted an IRE stem modification that is expected to markedly reduce the binding to iron-regulatory proteins."
The structural prediction linking this deletion to the shared mechanism; graded COMPUTATIONAL because it is an in-silico model rather than a binding assay.
💊

Medical Actions

3
Cataract Extraction
Category: Therapeutic Action: Cataract SurgeryNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is Cataract Surgery (NCIT:C157809). NCIT:C157809 is a clinical intervention from the NCI Thesaurus. NCIT:C157809
Platform: Surgery
The only established phenotype-directed intervention, and in most patients the only clinical consequence of the diagnosis. Standard lens extraction with intraocular lens implantation is performed when the opacity materially impairs vision; in a child with a dense cataract it is also the intervention that prevents deprivation amblyopia. Surgery removes the opaque lens, not the underlying derepression, so the serum ferritin is unchanged by it.
Mechanism Target:
BYPASSES Crystalline L-Ferritin Deposition and Lens Light Scattering — Extraction removes the tissue carrying the deposits rather than acting on the deposition process, which continues unchanged elsewhere.
Target Phenotypes: Bilateral early-onset cataract HP:0000519 Human Phenotype Ontology (HP) Relation: this treatment targets this phenotype This treatment targets Bilateral early-onset cataract, annotated with Developmental cataract (HP:0000519). HP:0000519 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:20511138 SUPPORT Human Clinical
"Patients diagnosed with HHCS should be counselled regarding the relative harmlessness of this genetic disease, with early cataract surgery as the only clinical consequence."
Establishes cataract surgery as the sole clinical intervention the diagnosis leads to.
PMID:30678075 SUPPORT Other
"Apart from the surgical removal of cataracts in HHCS, HHCS and L-ferritin deficiency have no specific therapy."
States explicitly that no therapy other than cataract removal exists, supporting the scope of this treatment entry.
Avoidance of Venesection, Iron Chelation and Liver Biopsy
Category: Therapeutic Action: Withholding of iron-depletion therapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is Withholding of iron-depletion therapy, annotated with Therapeutic Procedure (NCIT:C49236). NCIT:C49236 is a clinical intervention from the NCI Thesaurus. Ontology label: Therapeutic Procedure NCIT:C49236
Withholding iron-depletion therapy is a genuine intervention here rather than the absence of one, because the default management of a high ferritin is to remove iron and that default is harmful in HHCS. Phlebotomy cannot lower a translationally driven ferritin and instead induces iron deficiency; chelation is worse, having caused life-threatening hyperammonaemia in a child treated with deferasirox on a mistaken diagnosis; and liver biopsy, once routine in this work-up, is not indicated once the iron indices are normal. The correct action after diagnosis is to explain to the patient, and to record for future clinicians, that the ferritin is genetically driven and is not evidence of iron overload. Iron deficiency arising independently must still be treated on its own evidence, since the ferritin will not report it.
Show evidence (4 references)
PMID:21936912 SUPPORT Human Clinical
"Liver biopsy and phlebotomy should be avoided in this disorder."
A direct clinical recommendation to withhold both interventions, which is what this entry records.
PMID:41769540 SUPPORT Human Clinical
"Ferritin overproduction in HHCS is independent of iron availability; therefore, iron removal does not correct hyperferritinemia and may instead induce iron deficiency anemia and related clinical symptoms."
Gives the mechanistic reason the intervention is both futile and harmful.
PMID:33221470 SUPPORT Human Clinical
"Careful clinical evaluations and targeted genetic screening are important for avoiding potentially harmful treatments."
The study's own conclusion, drawn from the phlebotomy and deferasirox harms it reports.
+ 1 more reference
Genetic Counselling and Cascade Family Screening
Category: Counseling / Informational Action: Genetic CounselingNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is Genetic Counseling (NCIT:C15240). NCIT:C15240 is a clinical intervention from the NCI Thesaurus. NCIT:C15240
Once a proband is confirmed, first-degree relatives are offered targeted FTL testing, serum ferritin measurement and slit-lamp examination. This identifies affected relatives before they present, allows their cataracts to be followed and removed at the right time, and - the more important benefit in practice - prevents each of them from being separately worked up and venesected for a presumed haemochromatosis.
Show evidence (2 references)
PMID:41769540 SUPPORT Human Clinical
"Genetic counseling and cascade testing enable the identification of asymptomatic carriers, facilitate anticipatory guidance regarding cataract development, and prevent misinterpretation of ferritin elevations in affected relatives."
States all three benefits of cascade testing recorded in this entry.
PMID:16496261 SUPPORT Human Clinical
"Serum ferritin levels can be effectively used to screen for this condition in suspected families."
Supports serum ferritin as the cheap first-line screening test within a known family.
🔬

Biochemical Markers

2
Serum ferritin (Increased)
Context: The defining analyte and the reason nearly every patient is found. The value is generated by translation, not by iron, so it does not respond to iron removal and cannot be used to titrate any therapy. In HHCS it has also lost its ordinary meaning in the other direction, and will not fall to signal a genuine iron deficiency.
Pathograph Readouts
Readout Of Serum Hyperferritinemia Uncoupled from Body Iron Stores Positive Diagnostic
Reports the circulating pool of constitutively synthesised L-ferritin. High in every affected individual and unresponsive to iron manipulation.
Show evidence (1 reference)
PMID:9226182 SUPPORT Human Clinical
"By using monoclonal antibodies specific for the H and L ferritin subunits, serum ferritin was found to be essentially L type in both normal and affected individuals."
Establishes that the analyte measured in serum is the L-subunit species that this pathophysiology node overproduces.
Reference Ranges
Ferritin [Mass/volume] in Serum or Plasma 12.0–300.0 ug/L (adult males)
Serum ferritin reference intervals are strongly assay- and laboratory-dependent; a British series using a different assay quotes 15-360 microgram/L. Treat any single interval as indicative.
Show evidence (1 reference)
PMID:29269865 SUPPORT Human Clinical
"Normal serum ferritin levels are ranging from 12 to 300 µg/L for males and from 12 to 150 µg/L for females"
The reference interval this study measured its HHCS family against, quoted for the male stratum.
Ferritin [Mass/volume] in Serum or Plasma 12.0–150.0 ug/L (adult females)
Show evidence (1 reference)
PMID:29269865 SUPPORT Human Clinical
"Normal serum ferritin levels are ranging from 12 to 300 µg/L for males and from 12 to 150 µg/L for females"
The same source interval, quoted for the female stratum.
Show evidence (1 reference)
PMID:41769540 SUPPORT Human Clinical
"Serum ferritin was markedly elevated at 790 µg/L (reference range 23-333 µg/L)."
A worked example of the analyte and its local reference interval in a molecularly confirmed patient.
Transferrin saturation (Normal)
Context: The single most useful discriminating measurement, and a normal result is the finding that should stop a haemochromatosis work-up. Transferrin saturation indexes iron in transit, which HHCS does not disturb, whereas ferritin has been detached from iron entirely. Serum iron and total iron-binding capacity behave the same way.
Pathograph Readouts
Readout Of Serum Hyperferritinemia Uncoupled from Body Iron Stores Diagnostic
Normal in HHCS. No direction is recorded because the informative result is the absence of a change, and the direction enum has no value for that. Its normality alongside a very high ferritin is what establishes that the ferritin is not reporting body iron.
Show evidence (1 reference)
PMID:26849797 SUPPORT Human Clinical
"Serum ferritin concentrations were considerably elevated while serum iron, transferrin and transferrin saturation levels were within the normal range in each sibling."
Reports the dissociated pattern measured in all three affected siblings of one family.
Reference Ranges
Iron saturation [Mass Fraction] in Serum or Plasma 15.0–50.0 % (adults)
Show evidence (1 reference)
PMID:21936912 SUPPORT Human Clinical
"the serum transferrin saturation of 23.3% was within our laboratory reference interval (normal range 15-50%)"
Gives the laboratory reference interval against which the normal saturation in an HHCS patient was judged.
Show evidence (1 reference)
PMID:41300832 SUPPORT Human Clinical
"Diagnosis relies on the detection of persistently elevated serum ferritin with otherwise normal iron parameters (serum iron, transferrin saturation, and total iron-binding capacity), absence of inflammation or liver disease, and the presence of early-onset bilateral cataracts."
Places normal transferrin saturation, serum iron and TIBC at the centre of the diagnostic pattern.
🔬

Diagnosis

4
Isolated hyperferritinaemia with normal iron indices (Present)
The screening step. A persistently high serum ferritin with a normal serum iron, a normal transferrin saturation and a normal total iron-binding capacity, in a patient with no inflammation, no liver disease, no malignancy and no heavy alcohol intake, is the laboratory signature. Recognising it is what makes liver biopsy unnecessary.
Show evidence (2 references)
PMID:20511138 SUPPORT Human Clinical
"Laboratory test showing hyperferritinaemia, normal serum iron and normal transferrin saturation are indicative for HHCS after exclusion of other causes of increased ferritin levels (inflammation, malignancy, alcoholic liver disease) and should prompt an ophthalmological consultation for..."
States the laboratory triad and the exclusions, and names the next step.
PMID:20511138 SUPPORT Human Clinical
"Invasive diagnostics such as liver biopsy are not indicated."
Supports the claim that recognising the pattern removes the indication for biopsy.
Slit-lamp examination of the lens (Present)
Ophthalmological confirmation. Slit-lamp and retro-illumination examination shows the characteristic fine punctate and crystalline opacities, which are detectable in family members long before they are symptomatic and can therefore be used to establish the diagnosis in a proband and to screen relatives.
Show evidence (2 references)
PMID:16496261 SUPPORT Human Clinical
"Lens opacities were detectable in young members of the family, and morphology of cataracts was consistent with previous reports."
Shows that slit-lamp examination detects the opacities early and that the morphology is reproducible across families.
PMID:16496261 SUPPORT Human Clinical
"The morphology of cataracts in HHCS seems to be similar in all cases."
Supports the consistency of the appearance across affected individuals, which is what makes the examination diagnostically useful.
Sequencing of the FTL 5' untranslated region (Present)
Definitive confirmation. Targeted Sanger sequencing of the FTL 5' UTR and exon 1 identifies the causal variant. The test has to be requested specifically: the region is non-coding, so it is frequently absent from cataract and iron-disorder panels and poorly covered by exome filtering.
Show evidence (2 references)
PMID:41300832 SUPPORT Human Clinical
"Definitive diagnosis is established by identifying a pathogenic variant in the FTL IRE region through molecular testing"
Names molecular testing of the FTL IRE as the definitive diagnostic step.
PMID:28746593 SUPPORT Human Clinical
"For the definitive diagnosis, the affected patients, their parents and siblings were submitted to Sanger sequencing of the 5'UTR region for detection of the ferritin light gene mutation."
Describes the specific assay used, in probands and relatives, in a family study.
Exclusion of parenchymal iron overload by MRI (Absent)
Where doubt remains, quantitative liver MRI answers the iron-overload question non-invasively and replaces the liver biopsy that misdiagnosed patients have historically undergone.
Show evidence (1 reference)
PMID:41300832 SUPPORT Human Clinical
"Magnetic resonance imaging excluded systemic iron overload, while ophthalmological evaluation revealed bilateral cataracts."
A worked instance of MRI being used to exclude iron overload in a suspected HHCS case.
📊

Prevalence

2
Worldwide
Point Prevalence 0.5 per 100,000 1–9 per 1,000,000
The commonly quoted 1 in 200,000 figure is an expert estimate repeated across reviews, not a population-screening measurement, and every source that quotes it also says it is probably an underestimate because the disorder is misclassified as haemochromatosis. 1 in 200,000 is 0.5 per 100,000.
Show evidence (1 reference)
PMID:41300832 SUPPORT Human Clinical
"The estimated prevalence of HHCS is around 1 in 200,000 individuals, though this is likely underestimated due to underdiagnosis, especially in milder or subclinical cases"
States the prevalence estimate and its own caveat, which is why the record is written as an estimate.
Worldwide
Cases In Literature Ultra Rare
Two independent counts of the published corpus a few years apart give a consistent picture of a few hundred reported kindreds at most.
Show evidence (2 references)
PMID:29426274 SUPPORT Human Clinical
"About 160 families/unrelated cases with HHCS are known worldwide."
A direct count of the reported world literature at the time of publication.
PMID:41300832 SUPPORT Human Clinical
"Fewer than 200 families have been reported worldwide, often identified incidentally during evaluation of unexplained hyperferritinemia"
A more recent count, consistent with the earlier one, and it names incidental ascertainment as the usual route.
🔀

Differential Diagnoses

3

Conditions with similar clinical presentations that must be differentiated from Hereditary Hyperferritinemia with Congenital Cataracts:

Hereditary haemochromatosis
Overlapping Features The diagnosis HHCS is most often mistaken for, and the reason the mistake matters: haemochromatosis is treated by venesection, which in HHCS is futile and harmful. The discriminator is transferrin saturation, which is raised in haemochromatosis and normal in HHCS, together with the absence of parenchymal iron on imaging. Note that an incidental HFE H63D heterozygote is common in European populations and has been found alongside a confirmed FTL IRE variant without affecting the ferritin or hepcidin, so an HFE result does not settle the question either way.
Distinguishing Features
  • Transferrin saturation is raised in hereditary haemochromatosis and normal in HHCS.
  • Parenchymal iron is increased in haemochromatosis and absent on liver MRI or biopsy in HHCS.
  • Venesection lowers ferritin in haemochromatosis; in HHCS it produces iron deficiency while the ferritin stays high.
  • Early bilateral cataract, and a family history of it, belong to HHCS and are not features of haemochromatosis.
Show evidence (2 references)
PMID:41769540 SUPPORT Human Clinical
"Because elevated serum ferritin is commonly interpreted as a surrogate marker of iron overload, HHCS is frequently misdiagnosed as hereditary hemochromatosis or secondary iron overload, leading to unnecessary investigations and potentially harmful therapeutic phlebotomies."
States the confusion, its cause and its consequence.
PMID:41300832 SUPPORT Human Clinical
"Additional screening for common HFE variants revealed heterozygous H63D in several family members, with no impact on ferritin or hepcidin levels."
Supports the caveat that an incidental HFE variant coexists without explaining the ferritin.
Overlapping Features The other end of the FTL allelic series and the entity this one must not be merged with. Neuroferritinopathy is caused by coding-region FTL variants, mostly C-terminal, produces a progressive movement disorder with basal-ganglia iron accumulation, and runs with a low or normal serum ferritin - the opposite biochemical direction. Curated separately as `kb/disorders/neuroferritinopathy.yaml`.
Distinguishing Features
  • The HHCS lesion is non-coding, in the FTL 5' UTR IRE; the neuroferritinopathy lesion is in the FTL coding sequence.
  • Serum ferritin is high in HHCS and low or normal in neuroferritinopathy.
  • HHCS has no neurological manifestations; neuroferritinopathy is defined by chorea, dystonia and parkinsonism.
  • HHCS causes no tissue iron accumulation; neuroferritinopathy accumulates iron in the basal ganglia.
Show evidence (2 references)
PMID:30678075 SUPPORT Other
"Defects in the FTL gene lead to abnormally high levels of serum ferritin (hyperferritinemia) in HHCS and benign hyperferritinemia, while low levels (hypoferritinemia) are present in neuroferritinopathy and in autosomal dominant and recessive L-ferritin deficiency."
States the opposite biochemical directions of the two FTL disorders, which is the primary discriminator.
PMID:30678075 SUPPORT Other
"So far, there have been ten reported mutations causing this condition, mostly located at the C-terminal region of the FLT gene"
Locates the neuroferritinopathy alleles in the coding C-terminus, against the 5' UTR location of the HHCS alleles. The source's "FLT" is its own typographical error for FTL and is quoted as printed.
Benign hyperferritinaemia
Overlapping Features A third FTL disorder: dominant hyperferritinaemia without cataract and without iron overload, caused by missense changes in the first exon rather than in the IRE, with more than 90% of the circulating ferritin glycosylated. It is the differential for an isolated high ferritin in a family where slit-lamp examination is clean. Because HHCS cataract can be late, a young relative with a normal lens does not by itself distinguish the two.
Distinguishing Features
  • The lesion is in FTL exon 1 and changes the protein, not the IRE.
  • No cataract, at any age, in reported families.
  • More than 90% of serum ferritin is glycosylated.
Show evidence (2 references)
PMID:36768886 SUPPORT Other
"Benign hyperferritinemia is another rare dominant form of inherited hyperferritinemia not associated with iron overload or cataracts caused by mutations in FTL."
Defines the entity and its two distinguishing negatives.
PMID:36768886 SUPPORT Other
"This ferritin is susceptible to glycosylation, and the degree of glycosylation of serum ferritin is always greater than 90%."
Supplies the biochemical discriminator recorded in the distinguishing features.
{ }

Source YAML

click to show
name: Hereditary Hyperferritinemia with Congenital Cataracts
creation_date: '2026-09-05T18:30:00Z'
category: Mendelian
description: >-
  Hereditary hyperferritinemia-cataract syndrome (HHCS) is an autosomal dominant
  disorder caused by non-coding point mutations or small deletions in the
  iron-responsive element (IRE) in the 5' untranslated region of FTL. The IRE is
  the stem-loop that iron-regulatory proteins IRP1 and IRP2 occupy when cellular
  iron is low, blocking assembly of the translation preinitiation complex on
  L-ferritin mRNA. Variants that distort the hairpin lower or abolish IRP
  affinity, so L-ferritin translation runs constitutively and is no longer
  coupled to iron supply. The result is a very high serum ferritin with a normal
  serum iron and a normal transferrin saturation, and no parenchymal iron
  loading, together with bilateral early-onset cataract produced by crystalline
  L-ferritin deposits in lens fibre cells. Clinically the disorder is benign apart
  from the lens, and its main hazard is iatrogenic: because serum ferritin is
  routinely read as a surrogate for body iron stores, HHCS is repeatedly
  mistaken for hereditary haemochromatosis and treated with venesection or iron
  chelation, which cannot lower a genetically driven ferritin and instead
  produces iron deficiency. This entry is mechanistically distinct from
  `kb/disorders/neuroferritinopathy.yaml`, which is caused by FTL coding-region
  variants and features brain iron accumulation with low-to-normal serum
  ferritin.
disease_term:
  preferred_term: hereditary hyperferritinemia with congenital cataracts
  term:
    id: MONDO:0010952
    label: hereditary hyperferritinemia with congenital cataracts
synonyms:
- hereditary hyperferritinemia-cataract syndrome
- hyperferritinemia-cataract syndrome
- hereditary hyperferritinaemia cataract syndrome
- Bonneau-Beaumont syndrome
- HHCS
parents:
- hereditary disease
- eye disorder
- inherited disorder of iron metabolism
classifications:
  harrisons_chapter:
  - classification_value: ONCOLOGY_HEMATOLOGY
    notes: >-
      Almost every case is ascertained in a haematology, hepatology or general
      medical clinic during the work-up of an unexplained high serum ferritin,
      and the entity's practical importance is as a differential diagnosis of
      hyperferritinaemia rather than as an eye disease.
  - classification_value: GENETICS_ENVIRONMENT_DISEASE
    notes: >-
      A Mendelian dominant disorder whose lesion is a non-coding cis-regulatory
      element, which is also why coding-only gene panels miss it.
  icimd_category:
  - classification_value: iron_metabolism
    notes: >-
      Assigned by analogy with the other inherited disorders of iron-protein
      handling curated here (see `kb/disorders/IRIDA_Syndrome.yaml`). Note the
      qualification that matters clinically: HHCS deranges the regulation of an
      iron-storage protein, not iron flux itself, and body iron is normal.
inheritance:
- name: Autosomal dominant inheritance
  inheritance_term:
    preferred_term: Autosomal dominant inheritance
    term:
      id: HP:0000006
      label: Autosomal dominant inheritance
  description: >-
    Heterozygous FTL IRE variants segregate with both the hyperferritinaemia and
    the cataract through multiple generations. A negative family history does not
    exclude the diagnosis, because de novo variants occur. Rare homozygous
    individuals have been reported, and in at least one consanguineous family the
    homozygote had a markedly higher serum ferritin and the most severe cataract,
    indicating an allele-dose effect rather than a distinct recessive disease.
  evidence:
  - reference: PMID:7492760
    reference_title: "Molecular basis for the recently described hereditary hyperferritinemia-cataract syndrome: a mutation in the iron-responsive element of ferritin L-subunit gene (the \"Verona mutation\")."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "clinically characterized by the combination of elevated serum ferritin and congenital bilateral nuclear cataract, both cotransmitted as an autosomal dominant trait"
    explanation: The original clinical description establishes co-transmission of both features as a dominant trait.
  - reference: PMID:33221470
    reference_title: "Hereditary hyperferritinemia-cataract syndrome in three Czech families: molecular genetic testing and clinical implications."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Lack of family history does not exclude HHCS, because the pathogenic variant can arise de novo."
    explanation: Documents a paternity-confirmed de novo variant, so absence of an affected parent does not rule the diagnosis out.
  - reference: PMID:29269865
    reference_title: 'Functional characterization of a novel non-coding mutation "Ghent +49A > G" in the iron-responsive element of L-ferritin causing hereditary hyperferritinaemia-cataract syndrome.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The zygosity of the mutation, occurring in homozygous and heterozygous state in the proband and other affected family members respectively, correlated well with severity of ophthalmological and hematological manifestations."
    explanation: Supports an allele-dose effect in the rare homozygous state within an otherwise dominant disorder.
prevalence:
- population: Worldwide
  measure_type: POINT_PREVALENCE
  prevalence_class: BAND_1_9_PER_1000000
  rate_per_100000: 0.5
  notes: >-
    The commonly quoted 1 in 200,000 figure is an expert estimate repeated across
    reviews, not a population-screening measurement, and every source that quotes
    it also says it is probably an underestimate because the disorder is
    misclassified as haemochromatosis. 1 in 200,000 is 0.5 per 100,000.
  evidence:
  - reference: PMID:41300832
    reference_title: "Clinical and Molecular Clues to Diagnosing Hereditary Hyperferritinemia-Cataract Syndrome: Case Report and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The estimated prevalence of HHCS is around 1 in 200,000 individuals, though this is likely underestimated due to underdiagnosis, especially in milder or subclinical cases"
    explanation: States the prevalence estimate and its own caveat, which is why the record is written as an estimate.
- population: Worldwide
  measure_type: CASES_IN_LITERATURE
  prevalence_class: ULTRA_RARE
  notes: >-
    Two independent counts of the published corpus a few years apart give a
    consistent picture of a few hundred reported kindreds at most.
  evidence:
  - reference: PMID:29426274
    reference_title: "FTL c.-168G>C Mutation in Hereditary Hyperferritinemia Cataract Syndrome: A New Italian Family."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "About 160 families/unrelated cases with HHCS are known worldwide."
    explanation: A direct count of the reported world literature at the time of publication.
  - reference: PMID:41300832
    reference_title: "Clinical and Molecular Clues to Diagnosing Hereditary Hyperferritinemia-Cataract Syndrome: Case Report and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Fewer than 200 families have been reported worldwide, often identified incidentally during evaluation of unexplained hyperferritinemia"
    explanation: A more recent count, consistent with the earlier one, and it names incidental ascertainment as the usual route.
pathophysiology:
- name: FTL Iron-Responsive Element Disruption
  description: >-
    The initiating lesion is a heterozygous single-nucleotide substitution or
    short deletion inside the ~30-nucleotide IRE hairpin encoded in the FTL 5'
    untranslated region. The IRE has four structural parts that matter: a
    conserved CAGUGN apical hexanucleotide loop, an upper stem, an unpaired
    cytosine bulge separating the stems, and a lower stem. Pathogenic changes
    cluster in the loop, the bulge and the upper stem, and act by distorting or
    destabilising the hairpin so that it no longer presents the surface that
    iron-regulatory proteins recognise. The FTL coding sequence is untouched, so
    the L-ferritin protein produced is structurally normal - which is what
    separates this disorder from the coding-region FTL diseases.
  biological_scale: MOLECULAR
  mechanism_confidence: ESTABLISHED
  genes:
  - preferred_term: FTL
    term:
      id: hgnc:3999
      label: FTL
  genetic_context:
    variant_origin: GERMLINE
    zygosity: HETEROZYGOUS
    description: >-
      Constitutional non-coding variant in the FTL 5' UTR. Almost all reported
      patients are heterozygous; a handful of homozygous individuals have been
      described in consanguineous families. Deliberately no
      functional_impact_category is asserted here: the enum describes the
      activity of a gene product, and this variant does not change the product
      at all, only the amount of it that is made. The variant-level claim is
      carried instead by `regulatory_category` on the entries in `genetic`.
  evidence:
  - reference: PMID:7492760
    reference_title: "Molecular basis for the recently described hereditary hyperferritinemia-cataract syndrome: a mutation in the iron-responsive element of ferritin L-subunit gene (the \"Verona mutation\")."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "This mutation involves the five nucleotides sequence [CAGUG] of the iron-responsive element (IRE), which is critical for the posttranscriptional regulation of ferritin synthesis by means of IRE-binding protein (IRE-BP)."
    explanation: Identifies the conserved apical loop of the FTL IRE as the site of the founding mutation and states its regulatory role.
  - reference: PMID:20511138
    reference_title: "Hyperferritinaemia-cataract syndrome: worldwide mutations and phenotype of an increasingly diagnosed genetic disorder."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The most important sequences are a highly conserved hexanucleotide at the terminal loop, a bulge with an unpaired cytidin, and the upper stem of the hairpin"
    explanation: A survey of all mutations then reported localises the pathogenic changes to the loop, bulge and upper stem, which is the basis for the structural claim in this node.
  - reference: PMID:20511138
    reference_title: "Hyperferritinaemia-cataract syndrome: worldwide mutations and phenotype of an increasingly diagnosed genetic disorder."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Twenty-seven of these mutations are single nucleotide transitions and four are deletions of 2-29 base pairs."
    explanation: Establishes that the allelic spectrum is substitutions plus short deletions, not coding changes.
  downstream:
  - target: Loss of Iron-Regulatory Protein Binding to the FTL IRE
    causal_link_type: DIRECT
    description: >-
      A distorted hairpin no longer forms a high-affinity IRP-binding surface.
    evidence:
    - reference: PMID:7493028
      reference_title: Mutation in the iron responsive element of the L ferritin mRNA in a family with dominant hyperferritinaemia and cataract.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "We show that this mutation abolishes the binding of IRP in vitro and leads to a high constitutive, poorly regulated L-ferritin synthesis in cultured lymphoblastoid cells established from affected patients."
      explanation: Directly demonstrates that the IRE mutation is what abolishes IRP binding, which is the claim this edge makes.
- name: Loss of Iron-Regulatory Protein Binding to the FTL IRE
  description: >-
    In health, when cytosolic iron is low, IRP1 (in its apo, non-cluster form)
    and IRP2 bind the FTL IRE with high affinity and prevent recruitment of the
    small ribosomal subunit, so L-ferritin is not made. HHCS variants reduce that
    affinity. The reduction is graded rather than all-or-none: gel-shift assays
    across the allelic series show a spectrum from near-complete abolition to a
    partial, several-fold loss of affinity, and even a partial loss is enough to
    cause disease. This graded biochemistry is the mechanistic substrate for the
    clinical observation that different IRE positions give different disease
    severities.
  biological_scale: MOLECULAR
  mechanism_confidence: ESTABLISHED
  molecular_functions:
  - preferred_term: iron-responsive element binding by IRP1 and IRP2
    term:
      id: GO:0030350
      label: iron-responsive element binding
    modifier: DECREASED
  evidence:
  - reference: PMID:20511138
    reference_title: "Hyperferritinaemia-cataract syndrome: worldwide mutations and phenotype of an increasingly diagnosed genetic disorder."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Under conditions of intracellular iron depletion, both IRPs can bind IRE with high affinity, prevent binding of the translation initiation complex and thus block ferritin translation"
    explanation: States the normal repressive function this node reports the loss of. Graded OTHER because the source is a review summarising the physiology rather than reporting a study.
  - reference: PMID:9226182
    reference_title: "Hereditary hyperferritinemia-cataract syndrome: relationship between phenotypes and specific mutations in the iron-responsive element of ferritin light-chain mRNA."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Using a gel retardation assay, the observed molecular lesions were shown to variably reduce the IRE affinity for an iron regulatory protein (IRP), which inhibits ferritin mRNA translation."
    explanation: Demonstrates directly, and across more than one allele, that the lesions reduce IRE-IRP affinity, and that the reduction is variable.
  - reference: PMID:29269865
    reference_title: 'Functional characterization of a novel non-coding mutation "Ghent +49A > G" in the iron-responsive element of L-ferritin causing hereditary hyperferritinaemia-cataract syndrome.'
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "the WT IRE has an KDapp of 0.50 nM, while the +49A > G mutant IRE demonstrates a more than 5-fold lower affinity for IRP1, with an KDapp of 2.70 nM"
    explanation: Quantifies the affinity loss for one allele and shows it is partial, supporting the graded rather than all-or-none reading of this step.
  downstream:
  - target: Constitutive Derepression of L-Ferritin Translation
    causal_link_type: DIRECT
    description: >-
      Without IRP occupancy the preinitiation complex assembles on FTL mRNA
      irrespective of iron supply.
    evidence:
    - reference: PMID:29269865
      reference_title: 'Functional characterization of a novel non-coding mutation "Ghent +49A > G" in the iron-responsive element of L-ferritin causing hereditary hyperferritinaemia-cataract syndrome.'
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "abrogating the IRP/IRE interaction and leading to uncontrolled translation of FTL mRNA, independent of the iron status."
      explanation: States the causal step from lost IRP binding to iron-independent translation.
- name: Constitutive Derepression of L-Ferritin Translation
  description: >-
    Translation initiation on FTL mRNA becomes constitutive. This is the
    qualitative change that defines the disorder: the process is not simply
    running faster, it has been removed from the regulatory circuit that normally
    couples it to cytosolic iron, so neither iron loading nor iron chelation of
    the cell moves it. HHCS is the founding example of what has been called
    translational pathophysiology - disease caused by a mutation that changes how
    efficiently an mRNA is translated rather than what it encodes.
  biological_scale: MOLECULAR
  mechanism_confidence: ESTABLISHED
  biological_processes:
  - preferred_term: iron-independent initiation of L-ferritin mRNA translation
    term:
      id: GO:0006413
      label: translational initiation
    modifier: GAIN_OF_FUNCTION
  - preferred_term: IRP-mediated translational repression of FTL mRNA
    term:
      id: GO:0045947
      label: negative regulation of translational initiation
    modifier: LOSS_OF_FUNCTION
  evidence:
  - reference: PMID:10828006
    reference_title: "Translational pathophysiology: a novel molecular mechanism of human disease."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Hereditary hyperferritinemia/cataract syndrome arises from various point mutations or deletions within a protein-binding sequence in the 5'-UTR of the L-ferritin mRNA. Each unique mutation confers a characteristic degree of hyperferritinemia and severity of cataract in affected individuals."
    explanation: Frames HHCS as a translational-control disease and states the allele-specific dose relationship. Graded OTHER because this is a conceptual review rather than a primary study.
  - reference: PMID:9596665
    reference_title: Analysis of ferritins in lymphoblastoid cell lines and in the lens of subjects with hereditary hyperferritinemia-cataract syndrome.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Enzyme-linked immunosorbent assays specific for the H- and L-type ferritins showed that L-ferritin levels were up to 20-fold higher in HHCS than in control cells and were not affected by iron supplementation or chelation."
    explanation: The unresponsiveness to both iron loading and chelation is the direct demonstration that translation has left the regulatory circuit, which is why this node is graded qualitatively rather than as a simple increase.
  downstream:
  - target: L-Ferritin Overproduction and Intracellular Accumulation
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:34064225
      reference_title: "Hereditary Hyperferritinemia Cataract Syndrome: Ferritin L Gene and Physiopathology behind the Disease-Report of New Cases."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Mutations in the FTL IRE abrogate the interaction of FTL mRNA with the IRPs, and de-repress the expression of FTL protein. Subsequently, there is an overproduction of ferritin that accumulates in serum (hyperferritinemia) and excess ferritin precipitates in the lens, producing cataracts."
      explanation: States the step from derepressed translation to protein overproduction, and onward to both downstream branches of this pathograph.
- name: L-Ferritin Overproduction and Intracellular Accumulation
  description: >-
    Cells accumulate five- to twenty-fold excess L-ferritin. Because the excess is
    of one subunit only, the assembled product is abnormal in composition rather
    than in structure: roughly half of the surplus L-chain assembles into
    L-chain-only 24-mer homopolymers, which lack the H-subunit ferroxidase centre
    and therefore do not take up iron at all, and the remainder shifts the normal
    heteropolymer population towards L-rich isoferritins. This is the reason the
    disorder does not cause iron overload despite an enormous ferritin burden -
    the extra shells are essentially empty.
  biological_scale: CELLULAR
  mechanism_confidence: ESTABLISHED
  cellular_components:
  - preferred_term: L-chain-rich and L-chain-only ferritin shells
    term:
      id: GO:0070288
      label: ferritin complex
    modifier: INCREASED
  evidence:
  - reference: PMID:9596665
    reference_title: Analysis of ferritins in lymphoblastoid cell lines and in the lens of subjects with hereditary hyperferritinemia-cataract syndrome.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "in HHCS cells a large proportion of L-ferritin accumulates as nonfunctional L-chain 24 homopolymers"
    explanation: Establishes the L-chain homopolymer species that carries the excess.
  - reference: PMID:9596665
    reference_title: Analysis of ferritins in lymphoblastoid cell lines and in the lens of subjects with hereditary hyperferritinemia-cataract syndrome.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "the concomitant fivefold to 10-fold expansion of ferritin heteropolymers, with a shift to L-chain-rich isoferritins, does not have major effects on cellular iron metabolism"
    explanation: Supports both the compositional shift and the crucial negative claim that cellular iron handling is left intact.
  - reference: PMID:36768886
    reference_title: Hereditary Hyperferritinemia.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "leading to constitutive up-regulation of L-ferritin, intracellular accumulation of ferritin, mainly in the form of the homopolymers H0-L24, and hyperferritinemia"
    explanation: A recent review states the same subunit composition and links it forward to the hyperferritinaemia. Graded OTHER because it is a review synthesis.
  downstream:
  - target: Serum Hyperferritinemia Uncoupled from Body Iron Stores
    causal_link_type: DIRECT
    description: >-
      Circulating ferritin is a by-product of intracellular L-ferritin synthesis
      and secretion, so it tracks the intracellular excess.
    evidence:
    - reference: PMID:9226182
      reference_title: "Hereditary hyperferritinemia-cataract syndrome: relationship between phenotypes and specific mutations in the iron-responsive element of ferritin light-chain mRNA."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "There was a close relationship between mononuclear cell L-type ferritin content and serum ferritin concentration (r = 0.95, P < .00001), suggesting that the excess production of ferritin in cells was directly responsible for the hyperferritinemia."
      explanation: A quantitative within-patient correlation establishing that the serum level is driven by the intracellular excess rather than by leakage from damaged tissue.
  - target: Lens Fibre Cell L-Ferritin Accumulation
    causal_link_type: DIRECT
    description: >-
      The same derepression operates in the lens, where FTL is transcribed more
      heavily than in surrounding ocular tissue.
    evidence:
    - reference: PMID:29269865
      reference_title: 'Functional characterization of a novel non-coding mutation "Ghent +49A > G" in the iron-responsive element of L-ferritin causing hereditary hyperferritinaemia-cataract syndrome.'
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Interestingly, it has been demonstrated that endogenous FTL transcription is significantly higher in the lens compared to other eye tissues, which is likely to contribute to the pathogenic levels of FTL deposits found in HHCS lenses"
      explanation: Offers the tissue-level reason the systemic derepression lands hardest on the lens, which is what this edge asserts.
- name: Serum Hyperferritinemia Uncoupled from Body Iron Stores
  description: >-
    Serum ferritin is persistently and often markedly elevated, commonly in the
    several-hundred to greater-than-2,000 microgram/L range, while serum iron,
    transferrin saturation, total iron-binding capacity and parenchymal iron
    content stay normal. The clinically decisive point is negative: this is not
    iron overload. Serum ferritin has simply stopped being an index of body iron
    in these patients, in both directions - it will also fail to fall when they
    become genuinely iron deficient.
  biological_scale: ORGANISM
  mechanism_confidence: ESTABLISHED
  evidence:
  - reference: PMID:7492760
    reference_title: "Molecular basis for the recently described hereditary hyperferritinemia-cataract syndrome: a mutation in the iron-responsive element of ferritin L-subunit gene (the \"Verona mutation\")."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Differently from subjects with hereditary hemochromatosis, they have normal to low levels of serum iron and percent of transferrin saturation and absence of iron overload in parenchymal organs."
    explanation: States the dissociation between the ferritin level and every other index of body iron.
  - reference: PMID:41769540
    reference_title: "Hereditary Hyperferritinemia-Cataract Syndrome Misdiagnosed as Iron Overload: A Case Report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "While typically elevated in hereditary hemochromatosis, transferrin saturation remains normal in HHCS, reflecting preserved systemic iron homeostasis"
    explanation: Names transferrin saturation as the discriminating measurement and states that systemic iron homeostasis is preserved.
  - reference: PMID:36768886
    reference_title: Hereditary Hyperferritinemia.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "In patients with HHCS, serum ferritin is no longer a reliable indicator of iron stores in both iron deficiency and iron overload, which is something to keep in mind."
    explanation: Supports the bidirectional statement in this node's description, including the under-recognised risk of missing true iron deficiency.
  downstream:
  - target: Persistent Hyperferritinemia
    causal_link_type: DIRECT
  - target: Iatrogenic Iron Depletion from Misdirected Venesection and Chelation
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      The intervening step is not biological but interpretive: the high ferritin
      is read as evidence of iron overload and treated as haemochromatosis.
    intermediate_mechanisms:
    - Misattribution of isolated hyperferritinaemia to hereditary haemochromatosis
    evidence:
    - reference: PMID:20511138
      reference_title: "Hyperferritinaemia-cataract syndrome: worldwide mutations and phenotype of an increasingly diagnosed genetic disorder."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Many patients are initially misdiagnosed with hereditary haemochromatosis and treated with venesections that lead to rapid iron depletion and iron-deficiency anaemia."
      explanation: States the whole edge, including both its interpretive intermediate step and its harmful endpoint.
- name: Lens Fibre Cell L-Ferritin Accumulation
  description: >-
    Lens fibre cells accumulate L-ferritin far in excess of any other tissue
    examined. Measured lens L-ferritin content in HHCS ranges from about ten-fold
    the control value in one extracted nucleus to roughly 1500-fold in two others,
    the spread reflecting different assays, cataract morphologies and ages at
    surgery. Two features of the lens plausibly explain why this is the one tissue
    that suffers: FTL transcription is unusually high there, and lens fibre cells
    are post-mitotic, organelle-free and protein-packed, with no way to dilute or
    turn over an accumulating protein. The tissue selectivity is nonetheless not
    formally resolved - see the knowledge gap recorded in `discussions`.
  biological_scale: CELLULAR
  conforms_to: "cataract_lens_opacification#Lens Homeostasis Insult"
  mechanism_confidence: ESTABLISHED
  cell_types:
  - preferred_term: lens fibre cell
    term:
      id: CL:0011004
      label: lens fiber cell
  locations:
  - preferred_term: lens of the eye
    term:
      id: UBERON:0000965
      label: lens of camera-type eye
  evidence:
  - reference: PMID:9596665
    reference_title: Analysis of ferritins in lymphoblastoid cell lines and in the lens of subjects with hereditary hyperferritinemia-cataract syndrome.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "In addition, we analyzed the lens recovered from cataract surgery of a HHCS patient. We found it to contain about 10-fold more L-ferritin than control lens."
    explanation: Direct measurement of L-ferritin excess in an HHCS lens.
  - reference: PMID:11703332
    reference_title: "Clinical, biochemical and molecular findings in a series of families with hereditary hyperferritinaemia-cataract syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The lens ferritin content was analysed in two subjects who underwent cataract surgery at different ages, with different cataract morphology. Values were similar and about 1500-fold higher than in controls."
    explanation: A second, much larger measurement in two further lenses, and the source of the upper end of the range quoted here.
  - reference: PMID:29269865
    reference_title: 'Functional characterization of a novel non-coding mutation "Ghent +49A > G" in the iron-responsive element of L-ferritin causing hereditary hyperferritinaemia-cataract syndrome.'
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Although ferritin accumulates in all cell types of HHCS patients, it turns out to be toxic only in the crystallin-containing lens fiber cells."
    explanation: States the tissue selectivity that makes this a distinct node rather than a restatement of the systemic overproduction.
  downstream:
  - target: Crystalline L-Ferritin Deposition and Lens Light Scattering
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:10873976
      reference_title: The lens in hereditary hyperferritinaemia cataract syndrome contains crystalline deposits of L-ferritin.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "This unusual finding of crystalline opacities in the lens may be unique to HHCS and is likely to result from disturbed metabolism of L-ferritin within the lens or an abnormal interaction between L-ferritin and lens proteins."
      explanation: Attributes the crystalline opacities specifically to the excess lens L-ferritin, which is the claim this edge makes.
- name: Crystalline L-Ferritin Deposition and Lens Light Scattering
  description: >-
    The excess L-ferritin comes out of solution as discrete crystalline inclusions
    within the lens substance. Immunohistochemistry on an extracted HHCS lens
    stains these inclusions for L-ferritin and not for H-ferritin, so they are
    made of the overproduced subunit itself. Refractive-index discontinuities at
    the inclusions scatter incident light and degrade the image reaching the
    retina. Levi and colleagues additionally proposed that the L-chain excess
    perturbs the solubility equilibrium among the crystallins, or the lens
    antioxidant balance, as a contributing mechanism; that proposal has not been
    tested directly and is recorded here as a hypothesis rather than as the
    established route.
  biological_scale: TISSUE
  conforms_to: "cataract_lens_opacification#Loss of Lens Refractive Transparency and Light Scattering"
  mechanism_confidence: ESTABLISHED
  cell_types:
  - preferred_term: lens fibre cell
    term:
      id: CL:0011004
      label: lens fiber cell
  notes: >-
    Conformance caveat. The `cataract_lens_opacification` module routes its
    initiating insult through two crystallin-centred nodes - loss of crystallin
    solubility, then high-molecular-weight crystallin aggregate deposition -
    before reaching the light-scattering node this entry conforms to. HHCS
    largely bypasses that pair: the deposits are crystals of an overproduced
    non-crystallin protein, not aggregates of the crystallins themselves. The
    conformance is therefore declared at the two ends of the module chain, the
    lens insult and the optical consequence, and deliberately not at the
    crystallin-aggregation intermediate. Whether the crystallins are involved at
    all is exactly the untested part of the Levi hypothesis noted in this node's
    description.
  evidence:
  - reference: PMID:10873976
    reference_title: The lens in hereditary hyperferritinaemia cataract syndrome contains crystalline deposits of L-ferritin.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The cataract comprised discrete crystalline inclusions with positive staining with anti-L-ferritin but not anti-H-ferritin."
    explanation: Establishes both the crystalline morphology of the deposits and their L-ferritin composition.
  - reference: PMID:10873976
    reference_title: The lens in hereditary hyperferritinaemia cataract syndrome contains crystalline deposits of L-ferritin.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The HHCS lens L-ferritin content was 147 microg/g dry weight of lens compared with <16 microg/g for a non-HHCS control cataract lens."
    explanation: Quantifies the lens burden against a cataractous non-HHCS control, so the excess is not simply a feature of any cataract.
  - reference: PMID:36768886
    reference_title: Hereditary Hyperferritinemia.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Lens opacity probably results from overproduction of L-type ferritin, as shown by the presence of light-diffracting crystalline deposits rich in L-ferritin in cataractous lenses from individuals with HHCS"
    explanation: States the optical step - light diffraction by the deposits - that this node asserts. Graded OTHER because it is a review synthesis.
  - reference: PMID:9596665
    reference_title: Analysis of ferritins in lymphoblastoid cell lines and in the lens of subjects with hereditary hyperferritinemia-cataract syndrome.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "L-chain accumulation occurs also in the lens, where it may induce cataract formation by altering the delicate equilibrium between other water-soluble proteins (ie, crystallins) and/or the antioxidant properties."
    explanation: The source of the crystallin-equilibrium hypothesis recorded in this node's description; note the authors state it as a possibility, not a finding.
  downstream:
  - target: Bilateral Early-Onset Cataract
    causal_link_type: DIRECT
  - target: Pulverulent Lens Opacities
    causal_link_type: DIRECT
- name: Iatrogenic Iron Depletion from Misdirected Venesection and Chelation
  description: >-
    The commonest complication of HHCS is not caused by the disease. Because the
    ferritin elevation is generated by translation and not by stored iron,
    removing iron cannot correct it; what venesection does instead is strip a
    normal iron store from a patient who had one, producing iron deficiency and
    microcytic anaemia while the ferritin stays high. Iron chelation carries its
    own hazard: one 8.5-year-old treated with deferasirox on a mistaken diagnosis
    of iron overload developed life-threatening acute hyperammonaemia. Repeated
    liver biopsy for the same misdiagnosis is a further avoidable harm. This node
    is included in the pathograph because the harm is mechanistically predictable
    from the upstream biology, not because it is a property of the genotype.
  biological_scale: ORGANISM
  mechanism_confidence: ESTABLISHED
  evidence:
  - reference: PMID:7492760
    reference_title: "Molecular basis for the recently described hereditary hyperferritinemia-cataract syndrome: a mutation in the iron-responsive element of ferritin L-subunit gene (the \"Verona mutation\")."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "When unnecessary phlebotomies are performed, they rapidly develop iron-deficient anemia, with persistently elevated levels of serum ferritin."
    explanation: The original description already recorded both halves of the harm - the induced anaemia and the failure of the ferritin to fall.
  - reference: PMID:33221470
    reference_title: "Hereditary hyperferritinemia-cataract syndrome in three Czech families: molecular genetic testing and clinical implications."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "One individual, aged 43 years, underwent phlebotomy; another, aged 8.5 years, was treated with the iron chelator deferasirox, leading to life-threatening acute hyperammonemia, without severe liver injury."
    explanation: Documents the chelation arm of the harm and its severity in a specific patient.
  - reference: PMID:41769540
    reference_title: "Hereditary Hyperferritinemia-Cataract Syndrome Misdiagnosed as Iron Overload: A Case Report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "This intervention did not result in any clinically meaningful reduction in serum ferritin levels, supporting the absence of true iron overload."
    explanation: An observed instance of the futility of venesection in HHCS, which is the mechanistic point of this node.
  - reference: PMID:30678075
    reference_title: "L-Ferritin: One Gene, Five Diseases; from Hereditary Hyperferritinemia to Hypoferritinemia-Report of New Cases."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Some patients have received unnecessary invasive diagnostic techniques, such as liver biopsy, and are inappropriately treated with venesections and phlebotomies that can cause severe iron-deficiency anemia."
    explanation: Adds the invasive-diagnostic arm of the same harm pathway. Graded OTHER because it is a review that also reports new cases; the statement quoted is the review's synthesis.
  downstream:
  - target: Iron Deficiency Anemia
    causal_link_type: DIRECT
phenotypes:
- category: Ophthalmologic
  name: Bilateral Early-Onset Cataract
  description: >-
    Bilateral, generally symmetrical lens opacity, classically nuclear and often
    described as congenital. In practice the timing is variable: opacities may be
    present in infancy, first detected in childhood or adolescence, or not
    recognised until adult life. Two reported children extend that range past
    delay to absence: a newborn known to carry the variant had no detectable lens
    opacity at birth or at one year, and a separate paediatric proband had no
    lenticular opacities at all at the point of diagnosis and was placed under
    surveillance rather than treated. The cataract is slowly
    progressive and eventually requires extraction in most affected people. Age at
    diagnosis and at surgery vary widely both between and within families sharing
    the same allele.
  frequency: VERY_FREQUENT
  diagnostic: true
  phenotype_term:
    preferred_term: Bilateral early-onset cataract
    term:
      id: HP:0000519
      label: Developmental cataract
    laterality: BILATERAL
    clinical_course: PROGRESSIVE
  evidence:
  - reference: PMID:41300832
    reference_title: "Clinical and Molecular Clues to Diagnosing Hereditary Hyperferritinemia-Cataract Syndrome: Case Report and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Clinically, aside from isolated hyperferritinemia, the hallmark manifestation is progressive, bilateral cataract formation, usually developing in childhood or adolescence and often requiring surgical intervention"
    explanation: Supports the bilaterality, the early onset, the progressive course and the frequent need for surgery.
  - reference: PMID:15280904
    reference_title: Clinical features and molecular analysis of seven British kindreds with hereditary hyperferritinaemia cataract syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We report the clinical features of seven HHCS kindreds containing 49 individuals with premature cataract."
    explanation: The largest reported clinical series, establishing premature cataract as the constant clinical feature across kindreds.
  - reference: PMID:11703332
    reference_title: "Clinical, biochemical and molecular findings in a series of families with hereditary hyperferritinaemia-cataract syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A marked phenotypic variability was observed, particularly with regard to ocular involvement (i.e. age range at which cataract was diagnosed in 16 subjects with the C39T: 6-40 years)."
    explanation: Quantifies the within-allele variability in age at diagnosis stated in this description.
  - reference: PMID:11703332
    reference_title: "Clinical, biochemical and molecular findings in a series of families with hereditary hyperferritinaemia-cataract syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We followed an HHCS newborn in whom well-defined lens opacities were not detectable either at birth or at 1 year."
    explanation: The observation behind the caveat that the cataract is not invariably congenital despite the disease name.
  - reference: PMID:41281144
    reference_title: "Hereditary Hyperferritinemia-Cataract Syndrome: A Pediatric Case Without Congenital Cataract."
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: HUMAN_CLINICAL
    snippet: "reported on a pediatric case of HHCS that did not present with cataracts; this case, unlike our case, involved exclusively maternal relatives of the male proband harboring a different variant (A37C) in FTL"
    explanation: >-
      A 2025 report recording an earlier paediatric case that presented with no
      cataract at all, which is the strongest form of the not-invariably-congenital
      caveat: not merely delayed, but absent at presentation. Marked INDIRECT
      because the sentence is this paper's summary of a different paper's case
      (Serra et al. 2011), not an observation of its own; the primary report is
      not in the reference cache, so the inference step is the one from a
      secondary account to the case it describes.
  - reference: PMID:41281144
    reference_title: "Hereditary Hyperferritinemia-Cataract Syndrome: A Pediatric Case Without Congenital Cataract."
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: HUMAN_CLINICAL
    snippet: "At diagnosis, the child had no visual deficits or lenticular opacities but remains under regular follow-up for early cataract detection"
    explanation: >-
      The tabulated detail of that earlier case (Serra et al. 2011, as summarised
      in this report). Quoted from the 2025 paper because that is the cached
      source; the primary report is not in the reference cache. Marked INDIRECT
      for that reason - the quote is a secondary account of the case, not the
      case report itself.
  - reference: PMID:41281144
    reference_title: "Hereditary Hyperferritinemia-Cataract Syndrome: A Pediatric Case Without Congenital Cataract."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "While cataracts are the cardinal and well-documented ocular manifestation of HHCS, the correlation between genotype and the variability of the ocular phenotype, including factors such as age of onset and severity of cataracts, remains poorly understood"
    explanation: >-
      States that the determinants of ocular-phenotype variability are unknown,
      which is why this entry records the range of presentations rather than a
      genotype-based expectation. Graded OTHER rather than HUMAN_CLINICAL even
      though the publication is a case report: this particular sentence is the
      paper's review-style framing of the literature, not an observation of its
      own patient, which is how the same kind of sentence is graded on the
      venesection-harm node above (PMID:30678075).
  sequelae:
  - target: Visual Impairment
    causal_link_type: DIRECT
- category: Ophthalmologic
  name: Nuclear Cataract
  description: >-
    The opacity characteristically involves the embryonic and fetal lens nucleus,
    the part of the lens laid down earliest, which is consistent with an
    accumulation that begins in utero or in early life. Nuclear involvement was
    part of the original 1995 clinical definition and remains the most consistent
    morphology across series.
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Nuclear cataract
    term:
      id: HP:0100018
      label: Nuclear cataract
  evidence:
  - reference: PMID:7492760
    reference_title: "Molecular basis for the recently described hereditary hyperferritinemia-cataract syndrome: a mutation in the iron-responsive element of ferritin L-subunit gene (the \"Verona mutation\")."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "clinically characterized by the combination of elevated serum ferritin and congenital bilateral nuclear cataract, both cotransmitted as an autosomal dominant trait"
    explanation: Nuclear morphology is part of the founding clinical definition of the syndrome.
  - reference: PMID:36768886
    reference_title: Hereditary Hyperferritinemia.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Apart from hyperferritinemia, the only consistent abnormality in affected patients is a nuclear cataract, which appears in infancy or before the age of 50 years"
    explanation: A recent review calls nuclear cataract the one consistent abnormality, which is the basis for recording it separately from the general cataract phenotype.
- category: Ophthalmologic
  name: Pulverulent Lens Opacities
  description: >-
    The slit-lamp appearance is distinctive enough that experienced examiners have
    argued it should raise the diagnosis on its own. The opacities are fine,
    dust-like (pulverulent) or breadcrumb-like punctate flecks and small
    crystalline aggregates distributed axially and peripherally; larger series
    also describe a radial, sunflower-like arrangement in older lenses.
  frequency: FREQUENT
  diagnostic: true
  phenotype_term:
    preferred_term: Pulverulent, breadcrumb-like punctate lens opacities
    term:
      id: HP:0010693
      label: Pulverulent cataract
  notes: >-
    Lachlan and colleagues describe the morphology in their seven British kindreds
    as "sunflower" cataract, and HPO has a Sunflower cataract term (HP:6000642).
    It is deliberately not bound here: HPO defines that term as an anterior
    subcapsular copper deposit "almost only seen in Wilson disease", which is a
    different lesion in a different lens layer that merely shares a floral
    metaphor. Binding it would assert a Wilson-disease finding in an iron
    disorder. Pulverulent cataract, defined in HPO as punctate dust-like
    opacities of the fetal nucleus, matches the described lesion.
  evidence:
  - reference: PMID:20511138
    reference_title: "Hyperferritinaemia-cataract syndrome: worldwide mutations and phenotype of an increasingly diagnosed genetic disorder."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The cataract develops due to L-ferritin deposits in the lens and its pulverulent aspect is pathognomonic."
    explanation: States both the pulverulent morphology and its diagnostic weight, which is why this phenotype is flagged diagnostic.
  - reference: PMID:20511138
    reference_title: "Hyperferritinaemia-cataract syndrome: worldwide mutations and phenotype of an increasingly diagnosed genetic disorder."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The primary characteristics are the appearance of axial and peripheral white flecks and small crystalline aggregates."
    explanation: Describes the axial and peripheral flecks and crystalline aggregates recorded in this phenotype's description.
  - reference: PMID:15280904
    reference_title: Clinical features and molecular analysis of seven British kindreds with hereditary hyperferritinaemia cataract syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "All the probands developed characteristic 'sunflower' morphology cataracts in childhood (median age at diagnosis 5 years), but had no other phenotypic features."
    explanation: Source of the radial sunflower-like description and of the median age at diagnosis of five years; see this phenotype's notes for why the HPO Sunflower cataract term is not used.
- category: Ophthalmologic
  name: Visual Impairment
  description: >-
    Reduced vision from the lens opacity is the only symptom the syndrome causes.
    Severity ranges from an incidental slit-lamp finding to vision requiring
    extraction, and dense opacity present during the visual-development window
    carries the usual risk of deprivation amblyopia.
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Visual impairment
    term:
      id: HP:0000505
      label: Visual impairment
  evidence:
  - reference: PMID:11703332
    reference_title: "Clinical, biochemical and molecular findings in a series of families with hereditary hyperferritinaemia-cataract syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "No relevant symptoms other than visual impairment were found to be associated with the syndrome."
    explanation: A 62-patient series establishing visual impairment as the only symptom, which supports both the phenotype and the negative claim about the rest of the body.
- category: Laboratory
  name: Persistent Hyperferritinemia
  description: >-
    Lifelong elevation of serum ferritin, present from early life and usually
    found incidentally. Reported values in affected adults commonly run from a few
    hundred to well over 2,000 microgram/L; the original Verona family ranged from
    950 to 2,259 microgram/L, and the seven British kindreds had a median of 1,420
    microgram/L against a laboratory range of 15-360. Levels vary between and
    within families sharing an allele, and are not a reliable index of cataract
    severity in an individual.
  frequency: OBLIGATE
  diagnostic: true
  phenotype_term:
    preferred_term: Increased circulating ferritin concentration
    term:
      id: HP:0003281
      label: Increased circulating ferritin concentration
    temporality: CHRONIC
  evidence:
  - reference: PMID:7492760
    reference_title: "Molecular basis for the recently described hereditary hyperferritinemia-cataract syndrome: a mutation in the iron-responsive element of ferritin L-subunit gene (the \"Verona mutation\")."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In affected subjects, hyperferritinemia (ranging from 950 to 2,259 micrograms/L) is typically not related to iron overload."
    explanation: Gives the observed concentration range in the founding family and states that it is not iron-related.
  - reference: PMID:15280904
    reference_title: Clinical features and molecular analysis of seven British kindreds with hereditary hyperferritinaemia cataract syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "All the probands received diagnoses of HHCS after the incidental discovery of increased serum L-ferritin concentration (median 1420 microg/l; normal range 15-360 microg/l), in most cases during investigation or screening for anaemia."
    explanation: Supplies the median value and the local reference interval quoted in this description, and documents the incidental route to diagnosis.
- category: Hematologic
  name: Iron Deficiency Anemia
  description: >-
    Not a manifestation of the disorder but of its mistreatment. Patients
    venesected for a presumed haemochromatosis are drained of a normal iron store
    and become iron deficient and microcytic, while the ferritin they were being
    treated for does not move.
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Iron deficiency anemia following inappropriate venesection
    term:
      id: HP:0001891
      label: Iron deficiency anemia
  evidence:
  - reference: PMID:20511138
    reference_title: "Hyperferritinaemia-cataract syndrome: worldwide mutations and phenotype of an increasingly diagnosed genetic disorder."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "These patients had been initially misdiagnosed with hereditary haemochromatosis, although no iron overload had been found in liver biopsies and they developed iron-deficiency anaemia after repeated venesections."
    explanation: Records iron-deficiency anaemia as an observed consequence of venesection in misdiagnosed HHCS patients.
  - reference: PMID:34064225
    reference_title: "Hereditary Hyperferritinemia Cataract Syndrome: Ferritin L Gene and Physiopathology behind the Disease-Report of New Cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The proband and his daughter were treated as hereditary hemochromatosis with phlebotomies until they developed microcytic anemia."
    explanation: A named instance of the same harm, and the source of the microcytic descriptor used in this phenotype's description.
biochemical:
- name: Serum ferritin
  presence: Increased
  context: >-
    The defining analyte and the reason nearly every patient is found. The value
    is generated by translation, not by iron, so it does not respond to iron
    removal and cannot be used to titrate any therapy. In HHCS it has also lost
    its ordinary meaning in the other direction, and will not fall to signal a
    genuine iron deficiency.
  biomarker_term:
    preferred_term: serum L-ferritin
    term:
      id: NCIT:C224202
      label: Serum Ferritin
  readouts:
  - target: Serum Hyperferritinemia Uncoupled from Body Iron Stores
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      Reports the circulating pool of constitutively synthesised L-ferritin. High
      in every affected individual and unresponsive to iron manipulation.
    evidence:
    - reference: PMID:9226182
      reference_title: "Hereditary hyperferritinemia-cataract syndrome: relationship between phenotypes and specific mutations in the iron-responsive element of ferritin light-chain mRNA."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "By using monoclonal antibodies specific for the H and L ferritin subunits, serum ferritin was found to be essentially L type in both normal and affected individuals."
      explanation: Establishes that the analyte measured in serum is the L-subunit species that this pathophysiology node overproduces.
  reference_ranges:
  - loinc_term:
      id: LOINC:2276-4
      label: Ferritin [Mass/volume] in Serum or Plasma
    lower_bound: 12.0
    upper_bound: 300.0
    unit: ug/L
    population: adult males
    evidence:
    - reference: PMID:29269865
      reference_title: 'Functional characterization of a novel non-coding mutation "Ghent +49A > G" in the iron-responsive element of L-ferritin causing hereditary hyperferritinaemia-cataract syndrome.'
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Normal serum ferritin levels are ranging from 12 to 300 µg/L for males and from 12 to 150 µg/L for females"
      explanation: The reference interval this study measured its HHCS family against, quoted for the male stratum.
    notes: >-
      Serum ferritin reference intervals are strongly assay- and
      laboratory-dependent; a British series using a different assay quotes
      15-360 microgram/L. Treat any single interval as indicative.
  - loinc_term:
      id: LOINC:2276-4
      label: Ferritin [Mass/volume] in Serum or Plasma
    lower_bound: 12.0
    upper_bound: 150.0
    unit: ug/L
    population: adult females
    evidence:
    - reference: PMID:29269865
      reference_title: 'Functional characterization of a novel non-coding mutation "Ghent +49A > G" in the iron-responsive element of L-ferritin causing hereditary hyperferritinaemia-cataract syndrome.'
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Normal serum ferritin levels are ranging from 12 to 300 µg/L for males and from 12 to 150 µg/L for females"
      explanation: The same source interval, quoted for the female stratum.
  evidence:
  - reference: PMID:41769540
    reference_title: "Hereditary Hyperferritinemia-Cataract Syndrome Misdiagnosed as Iron Overload: A Case Report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Serum ferritin was markedly elevated at 790 µg/L (reference range 23-333 µg/L)."
    explanation: A worked example of the analyte and its local reference interval in a molecularly confirmed patient.
- name: Transferrin saturation
  presence: Normal
  context: >-
    The single most useful discriminating measurement, and a normal result is the
    finding that should stop a haemochromatosis work-up. Transferrin saturation
    indexes iron in transit, which HHCS does not disturb, whereas ferritin has
    been detached from iron entirely. Serum iron and total iron-binding capacity
    behave the same way.
  biomarker_term:
    preferred_term: transferrin saturation
    term:
      id: NCIT:C98792
      label: Transferrin Saturation Measurement
  readouts:
  - target: Serum Hyperferritinemia Uncoupled from Body Iron Stores
    relationship: READOUT_OF
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      Normal in HHCS. No direction is recorded because the informative result is
      the absence of a change, and the direction enum has no value for that. Its normality alongside a very high ferritin is what
      establishes that the ferritin is not reporting body iron.
    evidence:
    - reference: PMID:26849797
      reference_title: "Hyperferritinemia-cataract syndrome: Long-term ophthalmic observations in an Italian family."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Serum ferritin concentrations were considerably elevated while serum iron, transferrin and transferrin saturation levels were within the normal range in each sibling."
      explanation: Reports the dissociated pattern measured in all three affected siblings of one family.
  reference_ranges:
  - loinc_term:
      id: LOINC:2502-3
      label: Iron saturation [Mass Fraction] in Serum or Plasma
    lower_bound: 15.0
    upper_bound: 50.0
    unit: '%'
    population: adults
    evidence:
    - reference: PMID:21936912
      reference_title: "Hyperferritinemia without iron overload in patients with bilateral cataracts: a case series."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "the serum transferrin saturation of 23.3% was within our laboratory reference interval (normal range 15-50%)"
      explanation: Gives the laboratory reference interval against which the normal saturation in an HHCS patient was judged.
  evidence:
  - reference: PMID:41300832
    reference_title: "Clinical and Molecular Clues to Diagnosing Hereditary Hyperferritinemia-Cataract Syndrome: Case Report and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Diagnosis relies on the detection of persistently elevated serum ferritin with otherwise normal iron parameters (serum iron, transferrin saturation, and total iron-binding capacity), absence of inflammation or liver disease, and the presence of early-onset bilateral cataracts."
    explanation: Places normal transferrin saturation, serum iron and TIBC at the centre of the diagnostic pattern.
genetic:
- name: FTL
  gene_term:
    preferred_term: FTL
    term:
      id: hgnc:3999
      label: FTL
  relationship_type: CAUSATIVE
  presence: Present
  frequency: The only gene in which variants are known to cause HHCS
  notes: >-
    Pathogenic HHCS variants lie exclusively in the FTL 5' UTR IRE and are
    therefore invisible to a coding-only panel or to a conventional exome
    filtering strategy - a recurring reason for diagnostic delay. Two numbering
    conventions coexist in the literature: a historical one counting from the
    transcription start site and naming the allele after the city of first report
    (Paris-1 +40A>G, Verona-1 +41G>C), and HGVS c.- numbering from the ATG. FTL
    is allelic for four other phenotypes, including neuroferritinopathy; see
    `differential_diagnoses` and `kb/disorders/neuroferritinopathy.yaml`.
  evidence:
  - reference: PMID:34064225
    reference_title: "Hereditary Hyperferritinemia Cataract Syndrome: Ferritin L Gene and Physiopathology behind the Disease-Report of New Cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "At least 47 mutations have been described in FTL gene as causative of HHCS, including 36 single mutations, 9 deletions, and 2 insertion-deletions"
    explanation: States the size and composition of the allelic spectrum in the single causative gene.
  - reference: PMID:34064225
    reference_title: "Hereditary Hyperferritinemia Cataract Syndrome: Ferritin L Gene and Physiopathology behind the Disease-Report of New Cases."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "c.-160A>G is the same as the +40A>G Paris-1 mutation"
    explanation: Documents the equivalence of the two numbering conventions described in these notes.
  - reference: PMID:33221470
    reference_title: "Hereditary hyperferritinemia-cataract syndrome in three Czech families: molecular genetic testing and clinical implications."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Noncoding regions are often omitted from diagnostic gene panels, thus evading detection."
    explanation: Supports the diagnostic-ascertainment point made in these notes.
  variants:
  - name: FTL c.-168G>C
    description: >-
      A recurrent allele affecting the conserved three-nucleotide bulge of the
      FTL IRE, reported in Czech and Italian families among others.
    gene:
      preferred_term: FTL
      term:
        id: hgnc:3999
        label: FTL
    clinical_significance: PATHOGENIC
    regulatory_category: GOE
    evidence:
    - reference: PMID:29426274
      reference_title: "FTL c.-168G>C Mutation in Hereditary Hyperferritinemia Cataract Syndrome: A New Italian Family."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "This report documents a second Italian family, with a c.-168G>C mutation that is located in the highly conserved 3-nucleotide bulge structure of the FTL in the 5' untranslated region."
      explanation: Names the variant and localises it within the IRE bulge.
    - reference: PMID:41300832
      reference_title: "Clinical and Molecular Clues to Diagnosing Hereditary Hyperferritinemia-Cataract Syndrome: Case Report and Literature Review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Genetic testing confirmed a heterozygous FTL c.-168G>C variant."
      explanation: An independent family carrying the same allele, supporting its recurrence.
  - name: FTL c.-167C>T
    description: >-
      Documented arising de novo, with paternity confirmed - the allele that shows
      a negative family history cannot exclude the diagnosis.
    gene:
      preferred_term: FTL
      term:
        id: hgnc:3999
        label: FTL
    clinical_significance: PATHOGENIC
    regulatory_category: GOE
    evidence:
    - reference: PMID:33221470
      reference_title: "Hereditary hyperferritinemia-cataract syndrome in three Czech families: molecular genetic testing and clinical implications."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "but c.-167C>T occurred de novo (confirmed by paternity testing)"
      explanation: Establishes de novo occurrence of this specific allele with paternity testing.
  - name: FTL c.-151A>G (Ghent +49A>G)
    description: >-
      An upper-stem allele just above the cytosine bulge. Predicted to disrupt
      base pairing at the base of the upper stem and, through that, the apical
      loop and the bulge. Notable as the best-quantified example of a partial
      lesion: it reduces IRP1 affinity more than five-fold without abolishing
      binding, and still causes disease. Reported homozygous in a consanguineous
      family, where the homozygote was the most severely affected member.
    gene:
      preferred_term: FTL
      term:
        id: hgnc:3999
        label: FTL
    clinical_significance: PATHOGENIC
    regulatory_category: GOE
    evidence:
    - reference: PMID:29269865
      reference_title: 'Functional characterization of a novel non-coding mutation "Ghent +49A > G" in the iron-responsive element of L-ferritin causing hereditary hyperferritinaemia-cataract syndrome.'
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "The direct as well as competitive EMSA experiments show that +49A > G reduces, but not completely abolishes, the binding with recombinant IRP1."
      explanation: The functional result behind the partial-lesion description of this allele.
  - name: FTL IRE six-nucleotide deletion (Italian family)
    description: >-
      An example of the deletion class of HHCS alleles, in a repeat-containing
      stretch such that the deletion can be written four equivalent ways. Cited
      here to make the point that the allelic spectrum is not confined to
      substitutions.
    gene:
      preferred_term: FTL
      term:
        id: hgnc:3999
        label: FTL
    clinical_significance: PATHOGENIC
    regulatory_category: GOE
    evidence:
    - reference: PMID:11849230
      reference_title: A novel deletion of the L-ferritin iron-responsive element responsible for severe hereditary hyperferritinaemia-cataract syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "We report a novel six-nucleotide deletion identified in an Italian family presenting with elevated serum ferritin and early onset bilateral cataract."
      explanation: Documents a deletion allele and the phenotype it produced.
    - reference: PMID:11849230
      reference_title: A novel deletion of the L-ferritin iron-responsive element responsible for severe hereditary hyperferritinaemia-cataract syndrome.
      supports: SUPPORT
      evidence_source: COMPUTATIONAL
      snippet: "Structural modelling predicted an IRE stem modification that is expected to markedly reduce the binding to iron-regulatory proteins."
      explanation: The structural prediction linking this deletion to the shared mechanism; graded COMPUTATIONAL because it is an in-silico model rather than a binding assay.
diagnosis:
- name: Isolated hyperferritinaemia with normal iron indices
  description: >-
    The screening step. A persistently high serum ferritin with a normal serum
    iron, a normal transferrin saturation and a normal total iron-binding
    capacity, in a patient with no inflammation, no liver disease, no malignancy
    and no heavy alcohol intake, is the laboratory signature. Recognising it is
    what makes liver biopsy unnecessary.
  presence: Present
  evidence:
  - reference: PMID:20511138
    reference_title: "Hyperferritinaemia-cataract syndrome: worldwide mutations and phenotype of an increasingly diagnosed genetic disorder."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Laboratory test showing hyperferritinaemia, normal serum iron and normal transferrin saturation are indicative for HHCS after exclusion of other causes of increased ferritin levels (inflammation, malignancy, alcoholic liver disease) and should prompt an ophthalmological consultation for diagnostic confirmation."
    explanation: States the laboratory triad and the exclusions, and names the next step.
  - reference: PMID:20511138
    reference_title: "Hyperferritinaemia-cataract syndrome: worldwide mutations and phenotype of an increasingly diagnosed genetic disorder."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Invasive diagnostics such as liver biopsy are not indicated."
    explanation: Supports the claim that recognising the pattern removes the indication for biopsy.
- name: Slit-lamp examination of the lens
  description: >-
    Ophthalmological confirmation. Slit-lamp and retro-illumination examination
    shows the characteristic fine punctate and crystalline opacities, which are
    detectable in family members long before they are symptomatic and can
    therefore be used to establish the diagnosis in a proband and to screen
    relatives.
  presence: Present
  evidence:
  - reference: PMID:16496261
    reference_title: "Hereditary hyperferritinemia cataract syndrome: ocular, genetic, and biochemical findings."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Lens opacities were detectable in young members of the family, and morphology of cataracts was consistent with previous reports."
    explanation: Shows that slit-lamp examination detects the opacities early and that the morphology is reproducible across families.
  - reference: PMID:16496261
    reference_title: "Hereditary hyperferritinemia cataract syndrome: ocular, genetic, and biochemical findings."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The morphology of cataracts in HHCS seems to be similar in all cases."
    explanation: Supports the consistency of the appearance across affected individuals, which is what makes the examination diagnostically useful.
- name: Sequencing of the FTL 5' untranslated region
  description: >-
    Definitive confirmation. Targeted Sanger sequencing of the FTL 5' UTR and
    exon 1 identifies the causal variant. The test has to be requested
    specifically: the region is non-coding, so it is frequently absent from
    cataract and iron-disorder panels and poorly covered by exome filtering.
  presence: Present
  evidence:
  - reference: PMID:41300832
    reference_title: "Clinical and Molecular Clues to Diagnosing Hereditary Hyperferritinemia-Cataract Syndrome: Case Report and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Definitive diagnosis is established by identifying a pathogenic variant in the FTL IRE region through molecular testing"
    explanation: Names molecular testing of the FTL IRE as the definitive diagnostic step.
  - reference: PMID:28746593
    reference_title: Ferritin light chain gene mutations in two Brazilian families with hereditary hyperferritinemia-cataract syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "For the definitive diagnosis, the affected patients, their parents and siblings were submitted to Sanger sequencing of the 5'UTR region for detection of the ferritin light gene mutation."
    explanation: Describes the specific assay used, in probands and relatives, in a family study.
- name: Exclusion of parenchymal iron overload by MRI
  description: >-
    Where doubt remains, quantitative liver MRI answers the iron-overload question
    non-invasively and replaces the liver biopsy that misdiagnosed patients have
    historically undergone.
  presence: Absent
  evidence:
  - reference: PMID:41300832
    reference_title: "Clinical and Molecular Clues to Diagnosing Hereditary Hyperferritinemia-Cataract Syndrome: Case Report and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Magnetic resonance imaging excluded systemic iron overload, while ophthalmological evaluation revealed bilateral cataracts."
    explanation: A worked instance of MRI being used to exclude iron overload in a suspected HHCS case.
treatments:
- name: Cataract Extraction
  description: >-
    The only established phenotype-directed intervention, and in most patients the
    only clinical consequence of the diagnosis. Standard lens extraction with
    intraocular lens implantation is performed when the opacity materially impairs
    vision; in a child with a dense cataract it is also the intervention that
    prevents deprivation amblyopia. Surgery removes the opaque lens, not the
    underlying derepression, so the serum ferritin is unchanged by it.
  action_category: THERAPEUTIC
  therapeutic_modality: SURGERY
  treatment_term:
    preferred_term: Cataract Surgery
    term:
      id: NCIT:C157809
      label: Cataract Surgery
  target_phenotypes:
  - preferred_term: Bilateral early-onset cataract
    term:
      id: HP:0000519
      label: Developmental cataract
  target_mechanisms:
  - target: Crystalline L-Ferritin Deposition and Lens Light Scattering
    treatment_effect: BYPASSES
    description: >-
      Extraction removes the tissue carrying the deposits rather than acting on
      the deposition process, which continues unchanged elsewhere.
  evidence:
  - reference: PMID:20511138
    reference_title: "Hyperferritinaemia-cataract syndrome: worldwide mutations and phenotype of an increasingly diagnosed genetic disorder."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Patients diagnosed with HHCS should be counselled regarding the relative harmlessness of this genetic disease, with early cataract surgery as the only clinical consequence."
    explanation: Establishes cataract surgery as the sole clinical intervention the diagnosis leads to.
  - reference: PMID:30678075
    reference_title: "L-Ferritin: One Gene, Five Diseases; from Hereditary Hyperferritinemia to Hypoferritinemia-Report of New Cases."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Apart from the surgical removal of cataracts in HHCS, HHCS and L-ferritin deficiency have no specific therapy."
    explanation: States explicitly that no therapy other than cataract removal exists, supporting the scope of this treatment entry.
- name: Avoidance of Venesection, Iron Chelation and Liver Biopsy
  description: >-
    Withholding iron-depletion therapy is a genuine intervention here rather than
    the absence of one, because the default management of a high ferritin is to
    remove iron and that default is harmful in HHCS. Phlebotomy cannot lower a
    translationally driven ferritin and instead induces iron deficiency; chelation
    is worse, having caused life-threatening hyperammonaemia in a child treated
    with deferasirox on a mistaken diagnosis; and liver biopsy, once routine in
    this work-up, is not indicated once the iron indices are normal. The correct
    action after diagnosis is to explain to the patient, and to record for future
    clinicians, that the ferritin is genetically driven and is not evidence of
    iron overload. Iron deficiency arising independently must still be treated on
    its own evidence, since the ferritin will not report it.
  action_category: THERAPEUTIC
  treatment_term:
    preferred_term: Withholding of iron-depletion therapy
    term:
      id: NCIT:C49236
      label: Therapeutic Procedure
  evidence:
  - reference: PMID:21936912
    reference_title: "Hyperferritinemia without iron overload in patients with bilateral cataracts: a case series."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Liver biopsy and phlebotomy should be avoided in this disorder."
    explanation: A direct clinical recommendation to withhold both interventions, which is what this entry records.
  - reference: PMID:41769540
    reference_title: "Hereditary Hyperferritinemia-Cataract Syndrome Misdiagnosed as Iron Overload: A Case Report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Ferritin overproduction in HHCS is independent of iron availability; therefore, iron removal does not correct hyperferritinemia and may instead induce iron deficiency anemia and related clinical symptoms."
    explanation: Gives the mechanistic reason the intervention is both futile and harmful.
  - reference: PMID:33221470
    reference_title: "Hereditary hyperferritinemia-cataract syndrome in three Czech families: molecular genetic testing and clinical implications."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Careful clinical evaluations and targeted genetic screening are important for avoiding potentially harmful treatments."
    explanation: The study's own conclusion, drawn from the phlebotomy and deferasirox harms it reports.
  - reference: PMID:36768886
    reference_title: Hereditary Hyperferritinemia.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "In patients with HHCS, serum ferritin is no longer a reliable indicator of iron stores in both iron deficiency and iron overload, which is something to keep in mind."
    explanation: Supports the closing caveat that a genuine iron deficiency must be diagnosed by other means.
- name: Genetic Counselling and Cascade Family Screening
  description: >-
    Once a proband is confirmed, first-degree relatives are offered targeted FTL
    testing, serum ferritin measurement and slit-lamp examination. This identifies
    affected relatives before they present, allows their cataracts to be followed
    and removed at the right time, and - the more important benefit in practice -
    prevents each of them from being separately worked up and venesected for a
    presumed haemochromatosis.
  action_category: COUNSELING_INFORMATIONAL
  treatment_term:
    preferred_term: Genetic Counseling
    term:
      id: NCIT:C15240
      label: Genetic Counseling
  evidence:
  - reference: PMID:41769540
    reference_title: "Hereditary Hyperferritinemia-Cataract Syndrome Misdiagnosed as Iron Overload: A Case Report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Genetic counseling and cascade testing enable the identification of asymptomatic carriers, facilitate anticipatory guidance regarding cataract development, and prevent misinterpretation of ferritin elevations in affected relatives."
    explanation: States all three benefits of cascade testing recorded in this entry.
  - reference: PMID:16496261
    reference_title: "Hereditary hyperferritinemia cataract syndrome: ocular, genetic, and biochemical findings."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Serum ferritin levels can be effectively used to screen for this condition in suspected families."
    explanation: Supports serum ferritin as the cheap first-line screening test within a known family.
differential_diagnoses:
- name: Hereditary haemochromatosis
  description: >-
    The diagnosis HHCS is most often mistaken for, and the reason the mistake
    matters: haemochromatosis is treated by venesection, which in HHCS is futile
    and harmful. The discriminator is transferrin saturation, which is raised in
    haemochromatosis and normal in HHCS, together with the absence of parenchymal
    iron on imaging. Note that an incidental HFE H63D heterozygote is common in
    European populations and has been found alongside a confirmed FTL IRE variant
    without affecting the ferritin or hepcidin, so an HFE result does not settle
    the question either way.
  distinguishing_features:
  - Transferrin saturation is raised in hereditary haemochromatosis and normal in HHCS.
  - Parenchymal iron is increased in haemochromatosis and absent on liver MRI or biopsy in HHCS.
  - Venesection lowers ferritin in haemochromatosis; in HHCS it produces iron deficiency while the ferritin stays high.
  - Early bilateral cataract, and a family history of it, belong to HHCS and are not features of haemochromatosis.
  evidence:
  - reference: PMID:41769540
    reference_title: "Hereditary Hyperferritinemia-Cataract Syndrome Misdiagnosed as Iron Overload: A Case Report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Because elevated serum ferritin is commonly interpreted as a surrogate marker of iron overload, HHCS is frequently misdiagnosed as hereditary hemochromatosis or secondary iron overload, leading to unnecessary investigations and potentially harmful therapeutic phlebotomies."
    explanation: States the confusion, its cause and its consequence.
  - reference: PMID:41300832
    reference_title: "Clinical and Molecular Clues to Diagnosing Hereditary Hyperferritinemia-Cataract Syndrome: Case Report and Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Additional screening for common HFE variants revealed heterozygous H63D in several family members, with no impact on ferritin or hepcidin levels."
    explanation: Supports the caveat that an incidental HFE variant coexists without explaining the ferritin.
- name: Neuroferritinopathy
  description: >-
    The other end of the FTL allelic series and the entity this one must not be
    merged with. Neuroferritinopathy is caused by coding-region FTL variants,
    mostly C-terminal, produces a progressive movement disorder with basal-ganglia
    iron accumulation, and runs with a low or normal serum ferritin - the opposite
    biochemical direction. Curated separately as
    `kb/disorders/neuroferritinopathy.yaml`.
  disease_term:
    preferred_term: neuroferritinopathy
    term:
      id: MONDO:0011638
      label: neuroferritinopathy
  distinguishing_features:
  - The HHCS lesion is non-coding, in the FTL 5' UTR IRE; the neuroferritinopathy lesion is in the FTL coding sequence.
  - Serum ferritin is high in HHCS and low or normal in neuroferritinopathy.
  - HHCS has no neurological manifestations; neuroferritinopathy is defined by chorea, dystonia and parkinsonism.
  - HHCS causes no tissue iron accumulation; neuroferritinopathy accumulates iron in the basal ganglia.
  evidence:
  - reference: PMID:30678075
    reference_title: "L-Ferritin: One Gene, Five Diseases; from Hereditary Hyperferritinemia to Hypoferritinemia-Report of New Cases."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Defects in the FTL gene lead to abnormally high levels of serum ferritin (hyperferritinemia) in HHCS and benign hyperferritinemia, while low levels (hypoferritinemia) are present in neuroferritinopathy and in autosomal dominant and recessive L-ferritin deficiency."
    explanation: States the opposite biochemical directions of the two FTL disorders, which is the primary discriminator.
  - reference: PMID:30678075
    reference_title: "L-Ferritin: One Gene, Five Diseases; from Hereditary Hyperferritinemia to Hypoferritinemia-Report of New Cases."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "So far, there have been ten reported mutations causing this condition, mostly located at the C-terminal region of the FLT gene"
    explanation: Locates the neuroferritinopathy alleles in the coding C-terminus, against the 5' UTR location of the HHCS alleles. The source's "FLT" is its own typographical error for FTL and is quoted as printed.
- name: Benign hyperferritinaemia
  description: >-
    A third FTL disorder: dominant hyperferritinaemia without cataract and without
    iron overload, caused by missense changes in the first exon rather than in the
    IRE, with more than 90% of the circulating ferritin glycosylated. It is the
    differential for an isolated high ferritin in a family where slit-lamp
    examination is clean. Because HHCS cataract can be late, a young relative with
    a normal lens does not by itself distinguish the two.
  distinguishing_features:
  - The lesion is in FTL exon 1 and changes the protein, not the IRE.
  - No cataract, at any age, in reported families.
  - More than 90% of serum ferritin is glycosylated.
  evidence:
  - reference: PMID:36768886
    reference_title: Hereditary Hyperferritinemia.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Benign hyperferritinemia is another rare dominant form of inherited hyperferritinemia not associated with iron overload or cataracts caused by mutations in FTL."
    explanation: Defines the entity and its two distinguishing negatives.
  - reference: PMID:36768886
    reference_title: Hereditary Hyperferritinemia.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "This ferritin is susceptible to glycosylation, and the degree of glycosylation of serum ferritin is always greater than 90%."
    explanation: Supplies the biochemical discriminator recorded in the distinguishing features.
discussions:
- discussion_id: hhcs_lens_tissue_selectivity
  kind: KNOWLEDGE_GAP
  prompt: >-
    Why is the lens the only tissue damaged by an L-ferritin excess that is
    present in every cell of the body?
  attaches_to:
  - pathophysiology#Lens Fibre Cell L-Ferritin Accumulation
  - pathophysiology#Crystalline L-Ferritin Deposition and Lens Light Scattering
  rationale: >-
    The derepression is constitutive and ubiquitous - lymphoblastoid cells from
    patients carry up to twenty-fold excess L-ferritin - yet the only organ that
    is injured is the lens. Three partial explanations are on the table and none
    has been tested against the others. FTL transcription is measurably higher in
    the lens than in neighbouring ocular tissue, so the same fractional
    derepression yields a larger absolute burden there. Lens fibre cells are
    post-mitotic, organelle-free and cannot dilute or degrade an accumulating
    protein, so a small chronic surplus integrates over decades. And Levi and
    colleagues proposed that L-ferritin specifically perturbs the solubility
    equilibrium of the crystallins or the lens antioxidant defences, which would
    make the injury a property of the lens proteome rather than of dose or
    kinetics. Distinguishing these matters practically, because only the third
    predicts that the crystallins are involved, and the entry's conformance to
    `cataract_lens_opacification` is deliberately declared around, not through,
    that module's crystallin-aggregation node for exactly this reason.
  evidence:
  - reference: PMID:29269865
    reference_title: 'Functional characterization of a novel non-coding mutation "Ghent +49A > G" in the iron-responsive element of L-ferritin causing hereditary hyperferritinaemia-cataract syndrome.'
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Although ferritin accumulates in all cell types of HHCS patients, it turns out to be toxic only in the crystallin-containing lens fiber cells."
    explanation: States the puzzle this gap is about - ubiquitous accumulation, single-organ injury.
  - reference: PMID:29269865
    reference_title: 'Functional characterization of a novel non-coding mutation "Ghent +49A > G" in the iron-responsive element of L-ferritin causing hereditary hyperferritinaemia-cataract syndrome.'
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Interestingly, it has been demonstrated that endogenous FTL transcription is significantly higher in the lens compared to other eye tissues, which is likely to contribute to the pathogenic levels of FTL deposits found in HHCS lenses"
    explanation: The dose-based candidate explanation, offered by its own source as a likely contribution rather than a demonstrated cause.
  - reference: PMID:9596665
    reference_title: Analysis of ferritins in lymphoblastoid cell lines and in the lens of subjects with hereditary hyperferritinemia-cataract syndrome.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "L-chain accumulation occurs also in the lens, where it may induce cataract formation by altering the delicate equilibrium between other water-soluble proteins (ie, crystallins) and/or the antioxidant properties."
    explanation: The competing proteome-based explanation, likewise stated by its authors as a possibility.
- discussion_id: hhcs_genotype_severity_relationship
  kind: KNOWLEDGE_GAP
  prompt: >-
    Does IRE position predict phenotype severity well enough to be clinically
    useful, given how much variation there is between people carrying the same
    allele?
  attaches_to:
  - pathophysiology#Loss of Iron-Regulatory Protein Binding to the FTL IRE
  rationale: >-
    Two well-supported statements sit uneasily together. At the level of the
    allele, position in the IRE tracks severity: variants in the conserved apical
    hexanucleotide or the cytosine bulge give the highest ferritin values and the
    earliest, densest cataracts, while lower-stem variants can be nearly
    asymptomatic, and thermodynamic analysis correlates clinical severity with the
    extent of IRE-IRP disturbance. At the level of the patient, that signal
    largely disappears: the age at cataract diagnosis among sixteen carriers of a
    single allele spanned 6 to 40 years, ferritin values within one allele spanned
    700 to 2,412 microgram/L, and the largest clinical series found no clear
    relationship between genotype and clinical severity at all. Whether the
    residual variance is modifier genes, environmental exposure of the lens, or
    simply measurement noise in a small and heavily ascertained corpus is not
    known, and until it is, an IRE position cannot be used to counsel an
    individual family about when their child will need surgery.
  evidence:
  - reference: PMID:20511138
    reference_title: "Hyperferritinaemia-cataract syndrome: worldwide mutations and phenotype of an increasingly diagnosed genetic disorder."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Cazzola and co-workers showed that mutations in the highly conserved hexanucleotide region (eg at position 40 or 41) caused a severe cataract, while mutations around the bulge with unpaired cytidine (eg position 32) caused mild cataract."
    explanation: The allele-level position-severity relationship that makes the gap worth stating.
  - reference: PMID:15280904
    reference_title: Clinical features and molecular analysis of seven British kindreds with hereditary hyperferritinaemia cataract syndrome.
    supports: REFUTE
    evidence_source: HUMAN_CLINICAL
    snippet: "The severity of the clinical phenotype of HHCS was variable both within and between kindreds and showed no clear relationship to FTL genotype."
    explanation: The largest clinical series found no usable genotype-phenotype relationship, which is the observation that contradicts the allele-level claim above and is why this is recorded as an open question rather than a settled one.
  - reference: PMID:11703332
    reference_title: "Clinical, biochemical and molecular findings in a series of families with hereditary hyperferritinaemia-cataract syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Similarly, serum ferritin levels varied substantially also within subjects sharing the same mutation (i.e. range for the A40G: 700-2412 microg/l)."
    explanation: Quantifies the within-allele spread in ferritin quoted in the rationale.
notes: >-
  Entity verification. MONDO:0010952 was resolved against the OLS MONDO adapter
  before this entry was written and returns the label bound here, "hereditary
  hyperferritinemia with congenital cataracts". The causal gene recorded in the
  curation stub, hgnc:3999 FTL, was confirmed against the committed HGNC term
  cache. Both deep-research reports agree on OMIM 600886, which matches the MONDO
  record, and `just preflight-dr` returned PASS for the falcon report.


  Why the name is slightly wrong, and why it is kept. The MONDO label says
  "congenital cataracts", but the cataract is not reliably congenital: Girelli and
  colleagues followed a variant-carrying newborn who had no detectable lens
  opacity at birth or at one year, several later reports describe presentation in
  adolescence or adulthood, a 2025 paediatric report is titled for its case
  presenting without congenital cataract, and that report tabulates an earlier
  paediatric case (Serra et al. 2011) in whom there were no lenticular opacities
  at all at diagnosis. The two are different claims and were previously conflated
  here: the 2025 case is "without congenital cataract", not "without cataract". The entry keeps the MONDO name for its `name` and
  `disease_term` because that is the ontology anchor, and records the more
  accurate "early-onset" framing in the phenotype descriptions.


  Ontology decisions worth recording. Two bindings were considered and rejected.
  HP:6000642 Sunflower cataract matches the word used by the largest British
  series but not the lesion: HPO defines it as an anterior subcapsular copper
  deposit seen almost only in Wilson disease, so it was not bound - see the notes
  on the Pulverulent Lens Opacities phenotype. `functional_impact_category` was
  left unasserted on the pathophysiology `genetic_context`, because every value in
  that enum describes the activity of a gene product and this variant class leaves
  the product untouched; the variant-level claim is carried by
  `regulatory_category: GOE` on the `genetic.variants` entries instead. That
  choice is itself imperfect and is flagged here: the enum names GOE
  "gain of ectopic expression" and explicitly includes repressor-site disruption
  as a route to it, which fits, but the derepression in HHCS is regulatory and
  iron-independent rather than spatially ectopic. GOE is the only
  gain-of-expression value available and no better one exists today.


  Sources not used. PMID:15183095 (Hejtmancik and Kantorow, molecular genetics of
  age-related cataract) contains a good HHCS mechanism paragraph, but only in its
  full text; the cached record is abstract-only and holds nothing about HHCS, so
  it was fetched, read and dropped rather than cited from a passage the cache
  cannot verify. Its cache file has been removed accordingly - a committed cache
  for a reference nothing cites is an orphan. The falcon report cites Van de
  Sompele et al. 2017 by a DOI (10.1007/s00439-017-1835-3) that its own
  reference validation could not resolve;
  the same study is cited here as PMID:29269865, which resolves and whose cached
  full text contains every quoted passage. ORPHA:163 was not cited because
  generating an Orphanet cache entry requires a bulk rebuild that was out of scope
  for this session.


  Related entries. `kb/disorders/neuroferritinopathy.yaml` is the coding-region
  FTL disorder and is listed in `differential_diagnoses`; the two share a gene and
  nothing else mechanistically. `kb/disorders/IRIDA_Syndrome.yaml` and
  `kb/disorders/aceruloplasminemia.yaml` are the other inherited iron-handling
  entries in this knowledge base.
references:
- reference: PMID:7492760
  title: "Molecular basis for the recently described hereditary hyperferritinemia-cataract syndrome: a mutation in the iron-responsive element of ferritin L-subunit gene (the \"Verona mutation\")."
- reference: PMID:7493028
  title: Mutation in the iron responsive element of the L ferritin mRNA in a family with dominant hyperferritinaemia and cataract.
- reference: PMID:9226182
  title: "Hereditary hyperferritinemia-cataract syndrome: relationship between phenotypes and specific mutations in the iron-responsive element of ferritin light-chain mRNA."
- reference: PMID:9596665
  title: Analysis of ferritins in lymphoblastoid cell lines and in the lens of subjects with hereditary hyperferritinemia-cataract syndrome.
- reference: PMID:10828006
  title: "Translational pathophysiology: a novel molecular mechanism of human disease."
- reference: PMID:10873976
  title: The lens in hereditary hyperferritinaemia cataract syndrome contains crystalline deposits of L-ferritin.
- reference: PMID:11703332
  title: "Clinical, biochemical and molecular findings in a series of families with hereditary hyperferritinaemia-cataract syndrome."
- reference: PMID:11849230
  title: A novel deletion of the L-ferritin iron-responsive element responsible for severe hereditary hyperferritinaemia-cataract syndrome.
- reference: PMID:15280904
  title: Clinical features and molecular analysis of seven British kindreds with hereditary hyperferritinaemia cataract syndrome.
- reference: PMID:16496261
  title: "Hereditary hyperferritinemia cataract syndrome: ocular, genetic, and biochemical findings."
- reference: PMID:20511138
  title: "Hyperferritinaemia-cataract syndrome: worldwide mutations and phenotype of an increasingly diagnosed genetic disorder."
- reference: PMID:21936912
  title: "Hyperferritinemia without iron overload in patients with bilateral cataracts: a case series."
- reference: PMID:26849797
  title: "Hyperferritinemia-cataract syndrome: Long-term ophthalmic observations in an Italian family."
- reference: PMID:28746593
  title: Ferritin light chain gene mutations in two Brazilian families with hereditary hyperferritinemia-cataract syndrome.
- reference: PMID:29269865
  title: 'Functional characterization of a novel non-coding mutation "Ghent +49A > G" in the iron-responsive element of L-ferritin causing hereditary hyperferritinaemia-cataract syndrome.'
- reference: PMID:29426274
  title: "FTL c.-168G>C Mutation in Hereditary Hyperferritinemia Cataract Syndrome: A New Italian Family."
- reference: PMID:30678075
  title: "L-Ferritin: One Gene, Five Diseases; from Hereditary Hyperferritinemia to Hypoferritinemia-Report of New Cases."
- reference: PMID:33221470
  title: "Hereditary hyperferritinemia-cataract syndrome in three Czech families: molecular genetic testing and clinical implications."
- reference: PMID:34064225
  title: "Hereditary Hyperferritinemia Cataract Syndrome: Ferritin L Gene and Physiopathology behind the Disease-Report of New Cases."
- reference: PMID:36768886
  title: Hereditary Hyperferritinemia.
- reference: PMID:41300832
  title: "Clinical and Molecular Clues to Diagnosing Hereditary Hyperferritinemia-Cataract Syndrome: Case Report and Literature Review."
- reference: PMID:41769540
  title: "Hereditary Hyperferritinemia-Cataract Syndrome Misdiagnosed as Iron Overload: A Case Report."
📚

References & Deep Research

References

22
Molecular basis for the recently described hereditary hyperferritinemia-cataract syndrome: a mutation in the iron-responsive element of ferritin L-subunit gene (the "Verona mutation").
No top-level findings curated for this source.
Mutation in the iron responsive element of the L ferritin mRNA in a family with dominant hyperferritinaemia and cataract.
No top-level findings curated for this source.
Hereditary hyperferritinemia-cataract syndrome: relationship between phenotypes and specific mutations in the iron-responsive element of ferritin light-chain mRNA.
No top-level findings curated for this source.
Analysis of ferritins in lymphoblastoid cell lines and in the lens of subjects with hereditary hyperferritinemia-cataract syndrome.
No top-level findings curated for this source.
Translational pathophysiology: a novel molecular mechanism of human disease.
No top-level findings curated for this source.
The lens in hereditary hyperferritinaemia cataract syndrome contains crystalline deposits of L-ferritin.
No top-level findings curated for this source.
Clinical, biochemical and molecular findings in a series of families with hereditary hyperferritinaemia-cataract syndrome.
No top-level findings curated for this source.
A novel deletion of the L-ferritin iron-responsive element responsible for severe hereditary hyperferritinaemia-cataract syndrome.
No top-level findings curated for this source.
Clinical features and molecular analysis of seven British kindreds with hereditary hyperferritinaemia cataract syndrome.
No top-level findings curated for this source.
Hereditary hyperferritinemia cataract syndrome: ocular, genetic, and biochemical findings.
No top-level findings curated for this source.
Hyperferritinaemia-cataract syndrome: worldwide mutations and phenotype of an increasingly diagnosed genetic disorder.
No top-level findings curated for this source.
Hyperferritinemia without iron overload in patients with bilateral cataracts: a case series.
No top-level findings curated for this source.
Hyperferritinemia-cataract syndrome: Long-term ophthalmic observations in an Italian family.
No top-level findings curated for this source.
Ferritin light chain gene mutations in two Brazilian families with hereditary hyperferritinemia-cataract syndrome.
No top-level findings curated for this source.
Functional characterization of a novel non-coding mutation "Ghent +49A > G" in the iron-responsive element of L-ferritin causing hereditary hyperferritinaemia-cataract syndrome.
No top-level findings curated for this source.
FTL c.-168G>C Mutation in Hereditary Hyperferritinemia Cataract Syndrome: A New Italian Family.
No top-level findings curated for this source.
L-Ferritin: One Gene, Five Diseases; from Hereditary Hyperferritinemia to Hypoferritinemia-Report of New Cases.
No top-level findings curated for this source.
Hereditary hyperferritinemia-cataract syndrome in three Czech families: molecular genetic testing and clinical implications.
No top-level findings curated for this source.
Hereditary Hyperferritinemia Cataract Syndrome: Ferritin L Gene and Physiopathology behind the Disease-Report of New Cases.
No top-level findings curated for this source.
Hereditary Hyperferritinemia.
No top-level findings curated for this source.
Clinical and Molecular Clues to Diagnosing Hereditary Hyperferritinemia-Cataract Syndrome: Case Report and Literature Review.
No top-level findings curated for this source.
Hereditary Hyperferritinemia-Cataract Syndrome Misdiagnosed as Iron Overload: A Case Report.
No top-level findings curated for this source.

Deep Research

2

Deep research results are used as seeds for research; they do not undergo the same validation as the main records and may contain errors. How we use deep research.

Evaluations and curation notes (2)

Record notes

Entity verification. MONDO:0010952 was resolved against the OLS MONDO adapter before this entry was written and returns the label bound here, "hereditary hyperferritinemia with congenital cataracts". The causal gene recorded in the curation stub, hgnc:3999 FTL, was confirmed against the committed HGNC term cache. Both deep-research reports agree on OMIM 600886, which matches the MONDO record, and `just preflight-dr` returned PASS for the falcon report. Why the name is slightly wrong, and why it is kept. The MONDO label says "congenital cataracts", but the cataract is not reliably congenital: Girelli and colleagues followed a variant-carrying newborn who had no detectable lens opacity at birth or at one year, several later reports describe presentation in adolescence or adulthood, a 2025 paediatric report is titled for its case presenting without congenital cataract, and that report tabulates an earlier paediatric case (Serra et al. 2011) in whom there were no lenticular opacities at all at diagnosis. The two are different claims and were previously conflated here: the 2025 case is "without congenital cataract", not "without cataract". The entry keeps the MONDO name for its `name` and `disease_term` because that is the ontology anchor, and records the more accurate "early-onset" framing in the phenotype descriptions. Ontology decisions worth recording. Two bindings were considered and rejected. HP:6000642 Sunflower cataract matches the word used by the largest British series but not the lesion: HPO defines it as an anterior subcapsular copper deposit seen almost only in Wilson disease, so it was not bound - see the notes on the Pulverulent Lens Opacities phenotype. `functional_impact_category` was left unasserted on the pathophysiology `genetic_context`, because every value in that enum describes the activity of a gene product and this variant class leaves the product untouched; the variant-level claim is carried by `regulatory_category: GOE` on the `genetic.variants` entries instead. That choice is itself imperfect and is flagged here: the enum names GOE "gain of ectopic expression" and explicitly includes repressor-site disruption as a route to it, which fits, but the derepression in HHCS is regulatory and iron-independent rather than spatially ectopic. GOE is the only gain-of-expression value available and no better one exists today. Sources not used. PMID:15183095 (Hejtmancik and Kantorow, molecular genetics of age-related cataract) contains a good HHCS mechanism paragraph, but only in its full text; the cached record is abstract-only and holds nothing about HHCS, so it was fetched, read and dropped rather than cited from a passage the cache cannot verify. Its cache file has been removed accordingly - a committed cache for a reference nothing cites is an orphan. The falcon report cites Van de Sompele et al. 2017 by a DOI (10.1007/s00439-017-1835-3) that its own reference validation could not resolve; the same study is cited here as PMID:29269865, which resolves and whose cached full text contains every quoted passage. ORPHA:163 was not cited because generating an Orphanet cache entry requires a bulk rebuild that was out of scope for this session. Related entries. `kb/disorders/neuroferritinopathy.yaml` is the coding-region FTL disorder and is listed in `differential_diagnoses`; the two share a gene and nothing else mechanistically. `kb/disorders/IRIDA_Syndrome.yaml` and `kb/disorders/aceruloplasminemia.yaml` are the other inherited iron-handling entries in this knowledge base.

Create: Hereditary Hyperferritinemia with Congenital Cataracts · 2026-09-05T18:23:34Z · View source

Created kb/disorders/Hereditary_Hyperferritinemia_With_Congenital_Cataracts.yaml (MONDO:0010952, FTL / hgnc:3999, autosomal dominant) de novo, and deleted the corresponding curation stub. DEEP RESEARCH THAT ACTUALLY RAN. Two providers, both successfully, no fallback. (1) asta - research/Hereditary_Hyperferritinemia_With_Congenital_Cataracts-deep-research-asta.md, retrieval-only, 16 papers / 20 snippets, reference_validation 30/30 resolved, 0 unresolved, 0 off-topic, term_validation found no CURIEs to check. `just preflight-dr` returned WARN on this report: rival gene HFE at 26% of FTL mentions. That WARN was inspected and dismissed on reading - the HFE mentions are the misdiagnosis-as-haemochromatosis discussion that is the clinical core of this disease, and the CRYGD/BFSP2/MIP mentions come from five generic congenital-cataract papers Asta retrieved as topical noise (items 4, 7, 8, 11, 14). None of those five is cited in the entry. (2) falcon (Edison) - research/...-deep-research-falcon.md, 615 s, 59 citations, one artifact. `just preflight-dr` returned PASS (FTL 29 mentions, OMIM 600886 in both the report and MONDO). Its reference_validation flagged one unresolved identifier, DOI:10.1007/s00439-017-1835-3, given for Van de Sompele et al. 2017; it is not cited. Its term_validation flagged MONDO:0010952 as "mislabelled" against the reported label "if available", which is a template placeholder leaking into the report rather than a real term error - the CURIE and its label were confirmed independently against ols:mondo. GENEREVIEWS. There is no GeneReviews chapter for this disease. Searched PubMed two ways - `hyperferritinemia cataract GeneReviews[All Fields]` and `(hyperferritinemia[TI] AND cataract[TI]) AND GeneReviews[BOOK]` - both returned zero records. Per the skill, absence needs no workaround; the phenotype baseline was built instead from the two largest clinical series (PMID:15280904, 49 individuals across seven British kindreds; PMID:11703332, 62 patients in 14 families) plus the 2010 worldwide mutation-and-phenotype review (PMID:20511138) and the 2023/2025 reviews (PMID:36768886, PMID:41300832). MECHANISM MODEL AND WHY. An eight-node causal chain, MOLECULAR -> ORGANISM, with a branch: FTL Iron-Responsive Element Disruption -> Loss of Iron-Regulatory Protein Binding to the FTL IRE -> Constitutive Derepression of L-Ferritin Translation -> L-Ferritin Overproduction and Intracellular Accumulation, which then branches to (a) Serum Hyperferritinemia Uncoupled from Body Iron Stores and (b) Lens Fibre Cell L-Ferritin Accumulation -> Crystalline L-Ferritin Deposition and Lens Light Scattering. Every edge except two carries its own cited evidence separate from the node evidence. JUDGEMENT CALLS A REVIEWER SHOULD SEE. 1. The iatrogenic arm is modelled inside the pathograph, not left as prose. Serum Hyperferritinemia -> Iatrogenic Iron Depletion from Misdirected Venesection and Chelation is typed INDIRECT_KNOWN_INTERMEDIATES with the intermediate recorded explicitly as "Misattribution of isolated hyperferritinaemia to hereditary haemochromatosis", because the intervening step is interpretive rather than biological. That is a deliberate choice and it is argued in the node description. The harm is the clinically dominant fact about this disease (PMID:7492760, PMID:20511138, PMID:33221470, PMID:41769540, PMID:30678075) and it also drives a treatment entry (Avoidance of Venesection, Iron Chelation and Liver Biopsy) and the hereditary-haemochromatosis differential. 2. Modifier grading. GO:0006413 translational initiation is tagged GAIN_OF_FUNCTION and GO:0045947 negative regulation of translational initiation LOSS_OF_FUNCTION, rather than the default INCREASED/DECREASED, because the change is qualitative in exactly the sense CLAUDE.md reserves those values for: PMID:9596665 shows L-ferritin in patient cells is "not affected by iron supplementation or chelation", i.e. the process has left its regulatory circuit rather than merely running faster. By contrast GO:0030350 iron-responsive element binding is tagged DECREASED, which is quantitative and correct - PMID:29269865 measures a 5-fold affinity loss that does not abolish binding. 3. functional_impact_category is deliberately NOT set on the pathophysiology genetic_context, and the reason is written into the block. Every value in FunctionalImpactEnum describes the activity of a gene product; an IRE variant leaves the L-ferritin protein untouched and changes only how much is made. The variant-level claim is carried by regulatory_category: GOE on the four genetic.variants entries instead. GOE is itself imperfect - the enum titles it "gain of ectopic expression" and HHCS derepression is regulatory, not spatially ectopic - but its description explicitly lists repressor-site disruption as a route, it is the only gain-of-expression value available, and the mismatch is flagged in the entry notes rather than hidden. 4. Module conformance is declared around, not through, the cataract module. Two nodes conform to cataract_lens_opacification: Lens Fibre Cell L-Ferritin Accumulation -> "#Lens Homeostasis Insult", and Crystalline L-Ferritin Deposition and Lens Light Scattering -> "#Loss of Lens Refractive Transparency and Light Scattering". The module's two intermediate nodes are crystallin-centred (loss of crystallin solubility, then crystallin aggregate deposition) and HHCS largely bypasses them: the deposits are crystals of an overproduced non-crystallin protein. The caveat is recorded in that node's notes, and whether the crystallins are involved at all is the untested Levi hypothesis (PMID:9596665), captured as a knowledge-gap discussion. 5. HP:6000642 Sunflower cataract was considered and REJECTED even though PMID:15280904 calls the HHCS morphology "sunflower". HPO defines that term as an anterior subcapsular copper deposit "almost only seen in Wilson disease" - a different lesion in a different lens layer sharing a floral metaphor. HP:0010693 Pulverulent cataract (punctate dust-like opacities of the fetal nucleus) was bound instead. Reasoning is recorded on the phenotype and in the entry notes. 6. The MONDO label says "congenital cataracts" and the cataract is often not congenital (PMID:11703332 followed a variant-carrying newborn with no opacity at birth or one year). The MONDO name is kept for name/disease_term as the ontology anchor; the phenotype descriptions carry the accurate "early-onset" framing. Explained in notes. 7. Two reference_ranges are curated on serum ferritin (sex-stratified, PMID:29269865) and one on transferrin saturation (PMID:21936912), each with a citable evidence item rather than a free-text source, against LOINC:2276-4 and LOINC:2502-3. Both LOINC codes were looked up in the NLM Clinical Table Search Service, not written from memory. No interpretation_bands: HHCS has no graded severity tiers for ferritin, and the entry states explicitly that the value does not index cataract severity. REFERENCES CONSIDERED AND REJECTED. - PMID:15183095 (Hejtmancik and Kantorow, molecular genetics of age-related cataract) was fetched because Asta surfaced a good HHCS mechanism paragraph from it. That paragraph is full text only; the cached record is abstract-only and contains nothing about HHCS. Dropped rather than cited from text the cache cannot verify. - NCIT:C74736 was very nearly bound as "Transferrin Saturation" from memory. It is in fact "C-peptide Measurement". Caught by checking cache/ncit/terms.csv before validating; corrected to NCIT:C98792 Transferrin Saturation Measurement. Recorded here because the near-miss is exactly the failure mode the term contract exists for. - GO:0070288 ferritin complex was first used as the serum-ferritin biomarker_term; BiomarkerTerm is NCIT-only, so it was replaced with NCIT:C224202 Serum Ferritin. - ORPHA:163 is the Orphanet identifier for this disease but `just fetch-reference ORPHA:163` has no source; generating it needs a bulk Orphadata rebuild, which was out of scope for this session, so no ORPHA evidence is cited. - The five generic congenital-cataract papers in the Asta report (CRYGD, Cat-Map, WES cohorts) were read and not used: they are about cataract genetics in general, not this disease. NOT DONE. - No `datasets:` block. FTL dataset search is a textbook Named Entity Confusion trap - the gene's transcriptomic literature is dominated by neurodegeneration and by ferritin as an inflammatory marker, and this ultra-rare non-coding disorder has no omics corpus of its own (the falcon report independently reports finding no single-cell, spatial, proteomic, metabolomic or multi-omics HHCS study). Rather than attach accessions that resolve but are not about this disease, the block is omitted. This is the main reason global compliance is 94.5% and not higher. - No `animal_models:`, `experimental_models:` or `computational_models:`. No animal model of HHCS has been published; the falcon report reaches the same conclusion. The in-vitro work that exists (patient lymphoblastoid lines, recombinant IRP1 EMSA) is curated as evidence on the mechanism nodes rather than invented as model records. - No `clinical_trials:`. The only registered study the falcon report found (NCT05659017, "Candidate Gene for Hyperferritinemia") is observational with unknown status and is not an HHCS treatment trial; not curated. - classifications.harrisons_chapter and .icimd_category carry notes but no evidence items, matching the convention in kb/disorders/Methylmalonic_Aciduria_cblA_Type.yaml and IRIDA_Syndrome.yaml. VALIDATION ACTUALLY RUN, ALL TO COMPLETION. - `just validate kb/disorders/Hereditary_Hyperferritinemia_With_Congenital_Cataracts.yaml` -> schema "No issues found"; terms "Validation passed"; references "All validations passed", snippets 95/95 verified. - `just validate-disorders <file>` (the batched CI gate) -> all three stages pass, 95/95 snippets. - `just count-verified-snippets <file>` -> 95/95 verified, 0 skipped. - `just check-entity-refs <file>` -> OK. - `just check-causal-targets <file>` -> OK, no new broken targets. - `just check-duplicate-keys <file>` -> OK. - `just check-enum-values <file>` -> OK. - `just check-qualifier-terms <file>` -> OK (the entry uses no `qualifiers` blocks). - `just compliance <file>` -> Global 94.5% (172/182), Weighted 95.0%. - Self-checks scripted against the cache for this file only, since the corresponding repo recipes are whole-KB and this checkout is shared with other in-flight curation: all 117 (reference, reference_title) pairs match the cached frontmatter title; no snippet is a paper title; no snippet under 40 characters; no quoted sentence carries two different evidence_source values; no snippet uses a folded scalar. Whole-KB recipes (`just qc`, `just validate-all`, `just check-reference-titles`, `just check-snippet-grading`) were deliberately not run - six other agents are curating in this same working tree and their in-flight files would dominate the output.

Asta ▸
Asta Literature Retrieval: Pathophysiology and clinical mechanisms of Hereditary Hyperferritinemia with Congenital Cataracts. Core disease mecha...
Asta Scientific Corpus Retrieval 16 citations 2026-09-05T17:56:00.716128

Asta Literature Retrieval: Pathophysiology and clinical mechanisms of Hereditary Hyperferritinemia with Congenital Cataracts. Core disease mecha...

This report is retrieval-only and is generated directly from Asta results.

  • Papers retrieved: 16
  • Snippets retrieved: 20

Relevant Papers

[1] Hereditary Hyperferritinemia-Cataract Syndrome: A Pediatric Case Without Congenital Cataract

  • Authors: Anusha Hemanna, Richard Sidlow
  • Year: 2025
  • Venue: Cureus
  • URL: https://www.semanticscholar.org/paper/845f6f162d4735c88a7a50326b0fe232ae6b2ad3
  • DOI: 10.7759/cureus.95062
  • PMID: 41281144
  • PMCID: 12635498
  • Summary: A three-year-old male patient with incidentally detected hyperferritinemia who was found to harbor the c.-168G>T mutation in the FTL gene is reported, confirming hereditary hyperferritinemia-cataract syndrome (HHCS).
  • Evidence snippets:
  • Snippet 1 (score: 0.616) > Congenital, pediatric or early-onset cataracts, or unexplained hyperferritinemia in the absence of iron overload, either in isolation or in combination in an individual or a family, should raise clinical suspicion of HHCS. The diagnosis of HHCS was made after three generations of the patient's family showed an autosomal dominant inheritance pattern of hyperferritinemia with a history of cataracts. Hence, early identification of uncommon hereditary disorders is made possible by family history, which is a crucial screening tool for interpreting abnormal clinical findings. Our case, with its four-generation transmission primarily affecting males, raises the possibility of additional biological mechanisms, such as imprinting effects or sex-linked genetic/environmental modifiers, which merit further study. This case not only supports the importance of early diagnosis of HHCS but also suggests the need for further studies to elucidate the mechanisms of phenotypic variability, such as the age of cataract onset and the potential role of modifying factors. Further elucidation of these factors may lead to improvements in patient care and guide targeted therapy in the future. Prompt referral to a geneticist for directed testing of both the exonic and 5'-intronic space covering the FTL gene should follow the detection of these clinical findings and/or family history. Further research into the role of known variants causing this disease and clarification of genotype/phenotype correlations could reveal further insights into the iron regulation system, which is warranted.
  • Snippet 2 (score: 0.531) > The uncommon condition known as hereditary hyperferritinemia-cataract syndrome (HHCS) is typified by elevated serum ferritin levels, congenital bilateral cataracts, and no tissue iron overload [1,2]. Otherwise known as Bonneau-Beaumont Syndrome, this syndrome was initially identified as an autosomal dominant hereditary disease in 1995 by two separate research teams in France and Italy [3]. An important feature of HHCS is the progressive cataracts with highly distinctive morphology [4]. Approximately one in 200,000 people has the condition. However, this figure is likely understated since, even in cases where iron overload is not present, the illness is sometimes misdiagnosed as hereditary hemochromatosis because of hyperferritinemia. > The iron-responsive element (IRE) found upstream of the light ferritin gene (FTL) is mutated in HHCS. The gene product of a classical IRE is an mRNA structure that post-transcriptionally controls the production of proteins involved in iron metabolism by interacting with the iron regulatory proteins (IRP1 and IRP2). The FTL gene itself has been shown to contain at least 47 mutations that cause HHCS, including 36 singlenucleotide mutations, nine deletions, and two insertion-deletions [5]. Families with HHCS have been found to have at least 25 distinct genetic changes, including those affecting the complete IRE structure. There have also been reports of isolated instances brought on by de novo mutations [6]. While some of these genetic changes impact the stems or the bulge of the IRE structure and change its conformation, others disrupt the loop that directly interacts with iron regulatory proteins, which result in the uncontrolled synthesis of ferritin and inhibit iron binding [7,8]. > While cataracts are the cardinal and well-documented ocular manifestation of HHCS, the correlation between genotype and the variability of the ocular phenotype, including factors such as age of onset and severity of cataracts, remains poorly understood [4]. Broader awareness and early diagnosis of this entity when hyperferritinemia is detected have the potential to improve visual outcomes for patients.
  • Snippet 3 (score: 0.507) > Unlike Neofytou et al. (Table 2), who reported a sporadic case, our study identified a significant family history spanning four generations with congenital cataracts predominantly affecting males [9]. Furthermore, our genetic analysis revealed a heterozygous carrier status for the H63D variant of the HFE gene, contrasting with Alvarenga et al. (Table 2), who ruled out HFE gene mutations [10]. Notably, our study also found hyperferritinemia in first-degree relatives, differing from Morais et al. (Table 2), who reported normal ferritin levels in family members [11]. These differences highlight the complexity and variability of this condition. Serra et al. reported on a pediatric case of HHCS that did not present with cataracts; this case, unlike our case, involved exclusively maternal relatives of the male proband harboring a different variant (A37C) in FTL (Table 2) [12]. Our case involves four generations of exclusively male individuals, many of whom presented with congenital cataracts. Most other cases in the medical literature do not display such extreme gender specific segregation, which argues against an imprinting effect or segregation patterns being affected by the presence of specific exonic versus intronic variants driving the phenotype. However, given the paucity of cases reported to date, the preceding cannot be definitively ruled out. Additionally, there does not seem to be a correlation between the presence of a specific exonic versus intronic variant to explain the presence of congenital versus later onset of cataracts. However, genotype/phenotype correlation may be achievable based on measurement of time course of elevated ferritin levels as they relate to the specific variants known to cause HHCS to see if absolute levels or initiation/length of exposure to high ferritin levels may explain such this difference in phenotype (cataract formation in this syndrome being due to 10x elevation of ferritin levels within the lens). > Since hyperferritinemia is a biochemical indicator shared by both hereditary hemochromatosis and HHCS, the two conditions are misdiagnosed.

[2] Clinical and Molecular Clues to Diagnosing Hereditary Hyperferritinemia-Cataract Syndrome: Case Report and Literature Review

  • Authors: Barbora Ludíková, L. Sochorcova, D. Jakšić, K. Hlusickova Kapralova, M. Horvathova
  • Year: 2025
  • Venue: Genes
  • URL: https://www.semanticscholar.org/paper/b0919b844c289eca02277e771ba54b57c67730ff
  • DOI: 10.3390/genes16111381
  • PMID: 41300832
  • PMCID: 12652614
  • Citations: 1
  • Summary: A 12-year-old Czech girl with markedly elevated serum ferritin identified incidentally during workup for abdominal pain is evaluated, highlighting the translational relevance of combining molecular diagnostics, clinical evaluation, and family screening to improve recognition and management of HHCS and to prevent misdiagnosis and unnecessary iron-depletion therapy.
  • Evidence snippets:
  • Snippet 1 (score: 0.606) > Background: Hereditary hyperferritinemia-cataract syndrome (HHCS) is a rare autosomal dominant disorder characterized by persistently elevated serum ferritin and early-onset bilateral cataracts in the absence of systemic iron overload. It is caused by pathogenic variants in the iron-responsive element (IRE) of the FTL gene, leading to dysregulated L-ferritin synthesis. Methods: We evaluated a 12-year-old Czech girl with markedly elevated serum ferritin identified incidentally during workup for abdominal pain. Clinical assessment included biochemical, radiological, ophthalmological, and genetic testing of the proband and available family members. Results: Magnetic resonance imaging excluded systemic iron overload, while ophthalmological evaluation revealed bilateral cataracts. Family history indicated multiple affected relatives across three generations. Genetic testing confirmed a heterozygous FTL c.-168G>C variant. Additional screening for common HFE variants revealed heterozygous H63D in several family members, with no impact on ferritin or hepcidin levels. Beyond this case, we provide a comprehensive review of HHCS, including molecular mechanisms, an updated overview of reported FTL mutations, and ophthalmological features that distinguish HHCS cataracts from other congenital cataracts. Conclusions: This report underscores the translational relevance of combining molecular diagnostics, clinical evaluation, and family screening to improve recognition and management of HHCS, and to prevent misdiagnosis and unnecessary iron-depletion therapy.
  • Snippet 2 (score: 0.532) > Hereditary hyperferritinemia-cataract syndrome (HHCS, OMIM #600886) is a rare autosomal dominant disorder characterized by persistently elevated serum ferritin and early-onset bilateral cataracts without systemic iron overload. The condition is caused by pathogenic variants in the iron-responsive element (IRE) within the 5 ′ untranslated region (UTR) of the ferritin light chain (FTL) gene located on chromosome 19, which encodes the light (L)-ferritin subunit [1][2][3]. Under physiological conditions, the IRE forms a stem-loop structure that binds iron regulatory proteins (IRPs), thereby inhibiting translation of FTL mRNA when cellular iron levels are low [4]. In HHCS, pathogenic variants disrupt this regulatory mechanism, leading to constitutive overproduction of L-ferritin. > Clinically, aside from isolated hyperferritinemia, the hallmark manifestation is progressive, bilateral cataract formation, usually developing in childhood or adolescence and often requiring surgical intervention [5]. This results from excessive accumulation of L-ferritin in the lens, with characteristic crystalline deposits that scatter light and impair vision. The severity of cataracts and serum ferritin levels may correlate with the specific IRE mutation [2]. The estimated prevalence of HHCS is around 1 in 200,000 individuals, though this is likely underestimated due to underdiagnosis, especially in milder or subclinical cases [1]. Fewer than 200 families have been reported worldwide, often identified incidentally during evaluation of unexplained hyperferritinemia [6,7]. Diagnosis relies on the detection of persistently elevated serum ferritin with otherwise normal iron parameters (serum iron, transferrin saturation, and total iron-binding capacity), absence of inflammation or liver disease, and the presence of early-onset bilateral cataracts. Definitive diagnosis is established by identifying a pathogenic variant in the FTL IRE region through molecular testing [1][2][3].
  • Snippet 3 (score: 0.471) > Clinical and Molecular Clues to Diagnosing Hereditary Hyperferritinemia-Cataract Syndrome: Case Report and Literature Review

[3] Ferritin light chain gene mutations in two Brazilian families with hereditary hyperferritinemia-cataract syndrome

  • Authors: R. Petroni, Susana Elaine Alves da Rosa, Flavia Pereira de Carvalho, R. Santana, J. E. Hyppolito et al.
  • Year: 2017
  • Venue: Einstein
  • URL: https://www.semanticscholar.org/paper/7d3f0de34a2a255ad28fbd327c047996016f883a
  • DOI: 10.1590/S1679-45082017RC4006
  • PMID: 28746593
  • PMCID: 5875167
  • Citations: 2
  • Summary: For the definitive diagnosis of Hereditary hyperferritinemia-cataract syndrome, the affected patients, their parents and siblings were submitted to Sanger sequencing of the 5’UTR region for detection of the ferritin light gene mutation.
  • Evidence snippets:
  • Snippet 1 (score: 0.580) > Hyperferritinemia-cataract syndrome is a rare disease caused by mutations in the 5'UTR region of the FTL gene. While the prevalence of this syndrome has been estimated to be approximately 1/200,000 in Australia, (8) it is unknown in Brazil. Its clinical manifestations are congenital cataract and persistent hyperferritinemia, not associated with iron overload. Several frequent conditions are associated with congenital cataract, (5) and because of that, the search for mutation in the FTL gene is rarely included in the evaluation of congenital cataract, and most patients affected by this syndrome end up being evaluated by hyperferritinemia. As mutations in the HFE gene associated with hemochromatosis are frequent in our population, (7,(9)(10)(11) this is often the main presumptive diagnosis for these patients. The HFE gene is located on 6p22.2 and encodes a membrane protein that is thought to control iron absorption, by regulating the interaction of the transferrin receptor with transferrin. Mutations in this gene cause hereditary hemochromatosis, a recessive genetic disorder,

[4] Molecular genetics of age-related cataract.

  • Authors: J. Hejtmancik, M. Kantorow
  • Year: 2004
  • Venue: Experimental eye research
  • URL: https://www.semanticscholar.org/paper/645a402e8ba9a493f728af95c3f53c168d8a4e4f
  • DOI: 10.1016/J.EXER.2004.03.014
  • PMID: 15183095
  • Citations: 141
  • Influential citations: 5
  • Summary: Advances in molecular biological and genetic technology have greatly accelerated elucidation of the genetic contribution to age-related cataract. Epidemiological studies have documented tendencies for cataracts to occur more frequently in relatives of cataract patients than in the general population, genetic studies have demonstrated contributory roles of some specific genes in age related cataract in small populations, and molecular studies have shown changes in expression of specific genes...
  • Evidence snippets:
  • Snippet 1 (score: 0.565) > In addition to epidemiological evidence implicating genetic factors in age-related cataract, a number of inherited cataracts with post-infantile age of onset or progression of the opacity throughout life have been described. Mutations in BFSP2 can cause juvenile cataracts (Conley et al., 2000), the Marner and Volkmann cataracts can be progressive (Eiberg et al., 1995;Marner et al., 1989), mutations in aquaporin 0 (MIP) and γC-crystallin can cause progressive cataracts (Francis et al., 2000a;Ren et al., 2000), and the CAAR locus is linked to familial adult onset pulverulent cataracts (Heon et al., 2001). These all suggest that for at least some genes, a mutation that severely disrupts the protein or inhibits its function might result in congenital cataracts inherited in a highly penetrant Mendelian fashion, while a mutation that causes less severe damage to the same protein or impairs its function only mildly might contribute to age-related cataracts in a more complex multifactorial fashion. Similarly, mutations that severely disrupt the lens cell architecture or environment might produce congenital cataracts, while others that cause relatively mild disruption of lens cell homeostasis might contribute to age-related cataract. > The hyperferritinemia-cataract syndrome is a recently described disorder in which cataracts are associated with hyperferritinemia without iron overload (Beaumont et al., 1995). Ferritin L levels in the lens can increase dramatically. The molecular pathology lies in the Ferritin L iron responsive element, a stem loop structure in the 5′ untranslated region of the ferritin mRNA. Normally, this structure binds a cytoplasmic protein, the iron regulatory protein, which then inhibits translation of ferritin mRNA, which may exist in the lens at levels approaching that of a lens crystallin. Mutation of this structure and overexpression of ferritin by loss of translational control in the hyperferritinemia-cataract syndrome results in crystallization of ferritin in the lens, and other tissues as well. Ferritin

[5] Hyperferritinemia without iron overload in patients with bilateral cataracts: a case series

  • Authors: Arne Kröger, E. Bachli, Andrew D. Mumford, Christoph Gubler
  • Year: 2011
  • Venue: Journal of Medical Case Reports
  • URL: https://www.semanticscholar.org/paper/3dcfd7ab8c67377837188f0b1d30dcd9424fe726
  • DOI: 10.1186/1752-1947-5-471
  • PMID: 21936912
  • PMCID: 3189149
  • Citations: 1
  • Influential citations: 1
  • Summary: Hereditary hyperferritinemia cataract syndrome should be considered in all patients with unexplained hyperferritinemia without signs of iron overload, particularly those with juvenile bilateral cataracts.
  • Evidence snippets:
  • Snippet 1 (score: 0.524) > Hereditary hyperferritinemia cataract syndrome (HHCS) is a rare autosomal dominant genetic disease, which was first described in 1995 independently by the groups of Bonneau [1] and of Girelli [2]. They reported two families in whom elevated serum L-ferritin concentration without iron overload, presenting with juvenile bilateral cataracts, was inherited as an autosomal dominant trait [1,2]. Cataracts comprise crystalline deposits of L-ferritin. The underlying molecular defect in both the early reports of HHCS was identified as point mutations in the 5' untranslated region (5'UTR) of the L-ferritin gene (FTL), in the region corresponding to the iron-responsive element (IRE) of L-ferritin messenger ribonucleic acid (mRNA) [3,4]. These mutations lead to loss of suppression of L-ferritin mRNA translation by the iron-dependent iron regulatory protein (IRP) leading to dysregulated expression of the L-ferritin protein. Since these early reports, a series of other point mutations and short deletions of L-ferritin IRE associated with HHCS have been reported. > In 2000, Rososchova et al. measured serum ferritin concentrations in 135 Swiss patients with bilateral operated cataracts before the age of 51 to detect HHCS. However, no patients with HHCS were identified. This led those authors to postulate that HHCS is so rare that it might not exist in Switzerland [5]. We describe, to the best of our knowledge, the first two cases of HHCS in Switzerland, both with proven mutations in FTL. We also review key aspects of the metabolism of cellular iron and ferritin synthesis and we discuss the pathophysiology of HHCS.

[6] Hereditary hyperferritinemia-cataract syndrome: a case report

  • Authors: Hortência Morais, Yan Haddah, M. Mota, Adriana Ferreira, M. Lacordia et al.
  • Year: 2023
  • Venue: Residência Pediátrica
  • URL: https://www.semanticscholar.org/paper/f3c75e99245e3e3526610a308ac6e35bf6834c2d
  • DOI: 10.25060/residpediatr-2023.v13n2-533
  • Citations: 2
  • Summary: A case of SHHC in a healthy preschooler is reported, in which the finding of elevated ferritin was obtained in an occasional test, and its variable penetrance can make it difficult to perceive the hereditary character.
  • Evidence snippets:
  • Snippet 1 (score: 0.495) > Hereditary hyperferritinemia-cataract syndrome: a case report

[7] Inherited cataracts: molecular genetics, clinical features, disease mechanisms and novel therapeutic approaches

  • Authors: V. Berry, M. Georgiou, K. Fujinami, R. Quinlan, A. Moore et al.
  • Year: 2020
  • Venue: British Journal of Ophthalmology
  • URL: https://www.semanticscholar.org/paper/ffd6042f7542219ccae610d1589a703f96731754
  • DOI: 10.1136/bjophthalmol-2019-315282
  • PMID: 32217542
  • Citations: 71
  • Influential citations: 1
  • Summary: The variable cataract phenotypes and molecular mechanisms, including genotype–phenotype correlations, are detailed, and future novel therapeutic avenues including cellular therapies and pharmacological treatments are explored.
  • Evidence snippets:
  • Snippet 1 (score: 0.477) > Cataract is the most common cause of blindness in the world; during infancy and early childhood, it frequently results in visual impairment. Congenital cataracts are phenotypically and genotypically heterogeneous and can occur in isolation or in association with other systemic disorders. Significant progress has been made in identifying the molecular genetic basis of cataract; 115 genes to date have been found to be associated with syndromic and non-syndromic cataract and 38 disease-causing genes have been identified to date to be associated with isolated cataract. In this review, we briefly discuss lens development and cataractogenesis, detail the variable cataract phenotypes and molecular mechanisms, including genotype–phenotype correlations, and explore future novel therapeutic avenues including cellular therapies and pharmacological treatments.

[8] Case Report: Identification of a CRYGD variant in a family with congenital cataract

  • Authors: Junjie Deng, Jianli Ma, Yixiao Li, Wenjing Wang, Chunli Ma et al.
  • Year: 2026
  • Venue: Frontiers in Medicine
  • URL: https://www.semanticscholar.org/paper/becc27fc02999449edc889411a74c86835e7e732
  • DOI: 10.3389/fmed.2026.1778174
  • PMID: 42359092
  • PMCID: 13290538
  • Summary: This case may provide useful evidence for future variant interpretation and genetic counseling in congenital cataract families carrying CRYGD variants; however, further functional studies are required to clarify the pathogenic significance of c.391T>C (p.Trp131Arg).
  • Evidence snippets:
  • Snippet 1 (score: 0.472) > Congenital cataract is defined as lens opacity present at birth or developing during early infancy. Although congenital cataract is relatively uncommon in the general population, it is an important cause of preventable visual impairment in children worldwide (1). Epidemiological studies indicate that the prevalence of congenital cataract varies across populations, and genetic factors make a substantial contribution to its etiology. In hereditary cases, autosomal dominant inheritance is the most common pattern, although autosomal recessive and X-linked forms have also been reported (2)(3)(4)(5). > The molecular mechanisms underlying hereditary cataract are heterogeneous. Mutations in genes encoding lens structural proteins, membrane proteins, cytoskeletal proteins, transcription factors, and other developmental regulators have all been implicated. Among these, crystallin genes are among the most frequently reported disease-associated genes. CRYGD encodes γD-crystallin, a major structural protein that is essential for maintaining lens transparency and refractive properties (6,7). Variants in CRYGD have been associated with autosomal dominant congenital cataract in multiple populations (8)(9)(10)(11). > Recent studies have further confirmed the marked genetic heterogeneity of congenital cataract. In a 2025 cohort of 19 Chinese families with congenital cataract, WES followed by Sanger-based co-segregation analysis identified likely pathogenic variants in several cataract-associated genes, including CRYGD, GJA3, CRYAA, CRYBA1, BFSP2, IARS2, ARL2, and CRYBB3, with additional variants classified as VUS. Another 2025 study of 114 probands with congenital cataract also demonstrated broad genotype-phenotype heterogeneity involving isolated cataract, cataract with additional ocular anomalies, and cataract with multisystem abnormalities, supporting the value of WES for variant screening and genotype-phenotype correlation analysis in congenital cataract (12,13). > Despite substantial progress in identifying disease-related genes, the clinical interpretation of individual rare variants remains challenging, particularly when functional validation is unavailable.

[9] Hereditary Hyperferritinemia Cataract Syndrome: Case Report

  • Authors: Unknown authors
  • Year: 2020
  • Venue: Gazi Medical Journal
  • URL: https://www.semanticscholar.org/paper/a17f28fc79fce49e5d8c0174459472ac53ecf0d3
  • DOI: 10.12996/gmj.2020.108
  • Summary: Hereditary Hyperferritinemia-Cataract Syndrome (HHCS) is a rare disease characterized by cataract and hyperferritinemia. Herein, we present a pediatric patient diagnosed with HHCS.
  • Evidence snippets:
  • Snippet 1 (score: 0.471) > Hereditary Hyperferritinemia Cataract Syndrome: Case Report

[10] [Hereditary syndrome of hyperferritinemia and cataract].

  • Authors: J. Andonegui, M. Prat, M. Vargas
  • Year: 2007
  • Venue: Anales del sistema sanitario de Navarra
  • URL: https://www.semanticscholar.org/paper/1bad42e41c1c8c6f277590f194cead7be0dbb4ed
  • DOI: 10.23938/ASSN.0214
  • PMID: 17898822
  • Citations: 2
  • Influential citations: 1
  • Summary: This report describes a family with hereditary hyperferritinemia cataract syndrome, whose clinical characteristics are familial cataracts of early development and elevated serum ferritin levels but otherwise normal iron studies and haematological parameters.
  • Evidence snippets:
  • Snippet 1 (score: 0.462) > [Hereditary syndrome of hyperferritinemia and cataract].

[11] Congenital cataract – clinical and morphological aspects

  • Authors: C. Tătaru, C. Tătaru, A. Costache, O. Borugă, M. Zemba et al.
  • Year: 2020
  • Venue: Romanian Journal of Morphology and Embryology
  • URL: https://www.semanticscholar.org/paper/931a9bc039759d81bd94cc0560669b27263ef913
  • DOI: 10.47162/RJME.61.1.11
  • PMID: 32747900
  • PMCID: 7728133
  • Citations: 20
  • Summary: Clinically, the most frequent was the total cataract, followed by lamellar, nuclear and cerulean, and Morphologically, obvious changes were rendered evident at the level of anterior and posterior capsules, as well as subcapsular.
  • Evidence snippets:
  • Snippet 1 (score: 0.458) > Congenital cataract is a major cause of visual impairment in children [1]. It may occur as a single condition or in association with other ocular, somatic or neuropsychiatric disorders [6,12]. Congenital cataract identified at birth or in the first decade rises many unknown issues, henceforth their multiple clinical aspects [13]. > Congenital cataract is hereditary, up to 25% of the cases, of which 75% are autosomal dominant [14,15]. Today, 115 genes associated to syndromic and nonsyndromic cataract were found, while 38 genes were identified as causes of a cataract-associated disease [6]. > Genetic mutation affects various components in the lens structure. According to Shiels & Hejtmancik (2017), about 45% of the genetic mutations have an impact on crystallin proteins, about 16% of genetic mutations affect connexins, 12% act on growth and transcription factors, while 8% on metabolism, including the lipid metabolism [11]. The great clinical variety of congenital cataract is accounted for by the fact that the same genetic mutation generates radically different cataract phenotypes in different families; while differing genetic mutations can trigger similar morphological cataracts, which suggests that, apart from genetic mutations, there are additional factors, i.e., potential environmental factors that are involved in morphological variety [11]. > "Crystallins" represent over 90% of the soluble proteins existing in the human lens structure. They have a great importance in maintaining the refraction index in the lens [16]. In the human lens three main classes of "crystallins" have been identified, i.e., α-crystallin -representing 40%, β-crystallin -about 35% and γ-crystallin -25% [5,17,18]. > Mutations of genes codifying "crystallins" and "connexins" are found in congenital cataract, not associated with genetic syndromes, while mutations of α-crystallin lead to lamellar, nuclear and posterior polar cataract. > In literature, lamellar congenital cataract is thought to be the most frequently encountered form of cataract in pediatric patients [19].

[12] Hereditary Hyperferritinemia Cataract Syndrome: Ferritin L Gene and Physiopathology behind the Disease—Report of New Cases

  • Authors: Ferran Celma Nos, G. Hernández, X. Ferrer-Cortès, I. Hernández-Rodríguez, B. Navarro-Almenzar et al.
  • Year: 2021
  • Venue: International Journal of Molecular Sciences
  • URL: https://www.semanticscholar.org/paper/86b7c413f341ca6126ece14696f788f3c810eb75
  • DOI: 10.3390/ijms22115451
  • PMID: 34064225
  • PMCID: 8196845
  • Citations: 13
  • Influential citations: 1
  • Summary: Two new families affected with hereditary hyperferritinemia-cataract syndrome with previous known mutations are reported, and it is important to test serum ferritin levels in patients with cataracts.
  • Evidence snippets:
  • Snippet 1 (score: 0.457) > Hereditary Hyperferritinemia Cataract Syndrome: Ferritin L Gene and Physiopathology behind the Disease—Report of New Cases

[13] Hyperferritinaemia-cataract syndrome: Worldwide mutations and phenotype of an increasingly diagnosed genetic disorder

  • Authors: G. Millonig, M. Muckenthaler, S. Mueller
  • Year: 2010
  • Venue: Human Genomics
  • URL: https://www.semanticscholar.org/paper/6e851cf11d3b9dff5f9f4a8b66465212861800ea
  • DOI: 10.1186/1479-7364-4-4-250
  • PMID: 20511138
  • PMCID: 3525215
  • Citations: 49
  • Influential citations: 4
  • Summary: Haematologists, gastroenterologists and ophthalmologists should be aware of this syndrome to spare patients from further invasive diagnosis (liver biopsy), and also from a false diagnosis of hereditary haemochromatosis followed by venesections.
  • Evidence snippets:
  • Snippet 1 (score: 0.457) > Hyperferritinaemia-cataract syndrome: Worldwide mutations and phenotype of an increasingly diagnosed genetic disorder

[14] Whole Exome Sequencing of 20 Spanish Families: Candidate Genes for Non-Syndromic Pediatric Cataracts

  • Authors: Patricia Rodríguez-Solana, N. Arruti, M. Nieves-Moreno, R. Mena, Carmen Rodríguez-Jiménez et al.
  • Year: 2023
  • Venue: International Journal of Molecular Sciences
  • URL: https://www.semanticscholar.org/paper/8994a40a92f05aa1e83481e02a7baecbf8e11348
  • DOI: 10.3390/ijms241411429
  • PMID: 37511188
  • PMCID: 10380485
  • Citations: 10
  • Summary: LONP1, ACACA, TRPM1, CLIC5, HSPE1, ODF1, PIKFYVE, and CHMP4A are proposed as potential candidates to further investigate for their role in pediatric cataracts, and AQP5 and locus 2q37 as causal genes are proposed.
  • Evidence snippets:
  • Snippet 1 (score: 0.457) > Congenital cataracts were the first disease with autosomal dominant inheritance mapped in humans [17]. Although this pattern of inheritance predominates in pediatric cataracts of hereditary origin, autosomal recessive [18] and X-linked [19] patterns of inheritance have also been reported. > Non-syndromic congenital cataracts typically have complete penetrance, with autosomal dominant cataracts more common than recessive cataracts. Their expressivity is highly variable; thus, the same mutation within an affected family can give rise to various phenotypes. Furthermore, it is possible that the same type of cataract can be caused by mutations at different loci, making it a polygenic disease [6]. This complicated genotype-phenotype correlation complicates the genetic diagnosis of patients. > Currently, some 71 loci mapped to 56 cataract-causing genes have been identified [20]. This information is recorded in Cat-Map, a database that presents a chromosomal map together with the spectrum of mutations associated with hereditary cataracts, updated in real time [21]. The genetic causes of Mendelian cataracts can be grouped according to the cellular processes affected, suggesting that these pathways are critical for the correct development or homeostasis of the lens. Thus far, the most frequently implicated genes are those for crystallins (33%), developmental or transcription factors (26%), connexins (18%), membrane proteins and transporters (11%), genes involved in lipid metabolism (8%), and intermediate filament and chaperone proteins (4%) [20].

[15] Hereditary Hyperferritinemia-Cataract Syndrome Misdiagnosed as Iron Overload: A Case Report

  • Authors: Serkan Güven, Menekşe Öztürk
  • Year: 2026
  • Venue: Cureus
  • URL: https://www.semanticscholar.org/paper/3dd18039331ae262633475c1852ad650a8e54ced
  • DOI: 10.7759/cureus.102469
  • PMID: 41769540
  • PMCID: 12947710
  • Summary: The case of a 58-year-old male patient with longstanding unexplained hyperferritinemia, normal transferrin saturation, and a striking multigenerational family history of early-onset cataracts, highlights a critical diagnostic pitfall in hematology practice and emphasizes the importance of interpreting serum ferritin in conjunction with transferrin saturation.
  • Evidence snippets:
  • Snippet 1 (score: 0.457) > A 58-year-old male patient was referred to our hematology clinic for evaluation of persistent hyperferritinemia of unknown origin. Hyperferritinemia had been present for a long time according to the patient's history, although the exact duration was unknown. A single session of therapeutic phlebotomy was performed due to suspected iron overload and an elevated hemoglobin level. His medical history was notable for bilateral cataracts, first diagnosed in the fifth decade of life, which showed gradual progression and ultimately required bilateral cataract surgery. Family history revealed multiple affected relatives, including his father, five sisters, his daughter, and a grandchild, all of whom had early-onset cataracts accompanied by elevated ferritin levels, suggesting an autosomal dominant inheritance pattern. A detailed multigenerational pedigree diagram could not be constructed due to the incomplete availability of clinical and genetic information from all affected family members. Nevertheless, the observed vertical transmission across successive generations strongly supports an autosomal dominant inheritance pattern. > Physical examination was unremarkable, with no clinical signs suggestive of iron overload. Laboratory evaluation revealed a hemoglobin level of 15.7 g/dL, a white blood cell count of 7.78 × 10⁹/L, a platelet count of 156 × 10⁹/L, and a mean corpuscular volume of 90.5 fL. Enzyme-linked immunosorbent assay-based viral serologies, including hepatitis B surface antigen, anti-hepatitis C virus antibody, and HIV testing, were all negative. Serum ferritin was markedly elevated at 790 µg/L (reference range 23-333 µg/L). In contrast, serum iron concentration, transferrin saturation, liver function tests, and C-reactive protein levels were within normal limits, excluding iron overload, hepatic disease, and inflammation-related hyperferritinemia (Table 1). Abdominal ultrasonography demonstrated no hepatomegaly or evidence of hepatic iron deposition. The patient reported no history of alcohol consumption. Because of suspected hereditary hemochromatosis, a single session of therapeutic phlebotomy was performed prior to referral.

[16] L-Ferritin: One Gene, Five Diseases; from Hereditary Hyperferritinemia to Hypoferritinemia—Report of New Cases

  • Authors: B. Cadenas, Josep Fita-Torró, M. Bermúdez-Cortés, I. Hernández-Rodríguez, J. Fuster et al.
  • Year: 2019
  • Venue: Pharmaceuticals
  • URL: https://www.semanticscholar.org/paper/06a1aed362cacb43ebc25546c5b3b4fd921957cd
  • DOI: 10.3390/ph12010017
  • PMID: 30678075
  • PMCID: 6469184
  • Citations: 28
  • Influential citations: 1
  • Summary: A diagnostic algorithm is included for the detection of diseases caused by defects in FTL gene that cause dominant L-ferritin deficiency and HHCS and one previously reported variant (Met1Val) that causes dominant L+2T deficiency.
  • Evidence snippets:
  • Snippet 1 (score: 0.450) > According to our bioinformatics prediction, the c.375 + 2T > A mutation will not generate a dominant-negative version of FTL protein, but a truncated FTL protein completely missing the E-α-helix domain and partially lacking the D-α-helix domain. Supported by the clinical manifestations found in this family (low serum ferritin levels, low transferrin saturation and lack of serious neurological or movement abnormalities), the molecular mechanism in this case is most probably due to the loss of function of FTL and it will be not expected that the disease derives in neuroferritinopathy. However, we cannot totally and completely exclude the later development in life of brain iron overload and neuroferritinopathy in these patients by a yet unknown and novel mechanism. > Patients with hereditary hyperferritinemia could be misdiagnosed as patients suffering from hereditary hemochromatosis, liver dysfunction or inflammation. Some patients have received unnecessary invasive diagnostic techniques, such as liver biopsy, and are inappropriately treated with venesections and phlebotomies that can cause severe iron-deficiency anemia. On the other hand, clinical manifestations of neuroferritinopathy including tremor, parkinsonism, psychiatric problems, and abnormal involuntary movements, the presence of ferritin-iron precipitation in glia cells and neurons [30], are often misdiagnosed and treated as Huntington's or Parkinson's disease. Potential treatment targets for neuroferritinopathy may include an optimized iron chelator to induce the re-solubilization of iron aggregations, in combination with radical scavengers to prevent oxidative ferritin damage [35]. Patients with benign hyperferritinemia could be misdiagnosed as patients with HHCS due to the presence of high ferritin levels and the possible late-onset appearance of cataracts. Apart from the surgical removal of cataracts in HHCS, HHCS and L-ferritin deficiency have no specific therapy. > These facts emphasize the importance of a correct and early genetic diagnosis for the subsequent implementation of proper treatment, avoiding detrimental or inappropriate treatments.

Notes

  • This provider combines search_papers_by_relevance with snippet_search.
  • No synthesis or second-stage model call is performed.

Reference Validation

Checked with linkml-reference-validator 0.2.1.

Outcome Count
References checked 30
Resolved 30
Unresolved (possible confabulation) 0
Unverifiable 0
References weighed for topical relevance 30
On topic 16
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Falcon ▸
Disease Characteristics Research Template
Edison Scientific Literature 59 citations 2026-09-05T18:06:03.158779

Question: You are an expert researcher providing comprehensive, well-cited information.

Provide detailed information focusing on: 1. Key concepts and definitions with current understanding 2. Recent developments and latest research (prioritize 2023-2024 sources) 3. Current applications and real-world implementations 4. Expert opinions and analysis from authoritative sources 5. Relevant statistics and data from recent studies

Format as a comprehensive research report with proper citations. Include URLs and publication dates where available. Always prioritize recent, authoritative sources and provide specific citations for all major claims.

Disease Characteristics Research Template

Target Disease

  • Disease Name: Hereditary Hyperferritinemia with Congenital Cataracts
  • MONDO ID: MONDO:0010952 (if available)
  • Category: Mendelian

Research Objectives

Please provide a comprehensive research report on Hereditary Hyperferritinemia with Congenital Cataracts covering all of the disease characteristics listed below. This report will be used to populate a disease knowledge base entry. Be thorough and cite primary literature (PMID preferred) for all claims.

For each section, suggested databases/resources are listed. These are the first places you should search for information on each topic.


1. Disease Information

Search first: OMIM, Orphanet, ICD-10/ICD-11, MeSH, PubMed

  • What is the disease? Provide a concise overview.
  • What are the key identifiers? (OMIM, Orphanet, ICD-10/ICD-11, MeSH, Mondo)
  • What are the common synonyms and alternative names?
  • Is the information derived from individual patients (e.g., EHR) or aggregated disease-level resources?

2. Etiology

  • Disease Causal Factors: What are the primary causes? (genetic, environmental, infectious, mechanistic)
  • Risk Factors:

    Search first: PubMed, Cochrane Library, UpToDate, clinical guidelines, ClinVar, ClinGen, GWAS Catalog, PheGenI, CTD, CDC, WHO, epidemiological databases

  • Genetic risk factors (causal variants, susceptibility loci, modifier genes)
  • Environmental risk factors (toxins, lifestyle, occupational exposures, age, sex, family history)
  • Protective Factors:

    Search first: PubMed, Cochrane Library, clinical trial databases, GWAS Catalog, gnomAD, WHO, CDC, nutrition databases

  • Genetic protective factors (protective variants, modifier alleles)
  • Environmental protective factors (diet, lifestyle, exposures that reduce risk)
  • Gene-Environment Interactions: How do genetic and environmental factors interact to influence disease?

    Search first: CTD, PubMed, PheGenI, GxE databases

3. Phenotypes

Search first: HPO (Human Phenotype Ontology), OMIM, Orphanet, PubMed, clinicaltrials.gov, MedDRA, SNOMED CT, DECIPHER, LOINC

For each phenotype, provide: - Phenotype type: symptoms, clinical signs, physical manifestations, behavioral changes, or laboratory abnormalities

For symptoms/signs: HPO, OMIM, Orphanet, PubMed For behavioral changes: HPO, DSM, RDoC (Research Domain Criteria), PubMed For laboratory abnormalities: LOINC, SNOMED CT, LabTests Online, PubMed - Phenotype characteristics: Search first: OMIM, Orphanet, HPO, PubMed - Age of symptom onset (neonatal, childhood, adult-onset, late-onset) - Symptom severity (mild, moderate, severe, variable) - Symptom progression (stable, progressive, episodic, fluctuating) - Frequency among affected individuals (percentage or qualitative) - Quality of life impact: Effects on daily functioning and well-being (per-phenotype when possible) Search first: EQ-5D database, SF-36, WHO QOL databases, PubMed - Suggest HPO (Human Phenotype Ontology) terms for each phenotype

4. Genetic/Molecular Information

  • Causal Genes: Gene mutations or chromosomal abnormalities responsible for disease (gene symbols, OMIM IDs)

    Search first: OMIM, ClinVar, HGMD, Ensembl, NCBI Gene

  • Pathogenic Variants:
  • Affected genes (gene symbols, HGNC IDs) > Search first: OMIM, NCBI Gene, Ensembl, HGNC, UniProt, GeneCards
  • Variant classification (pathogenic, likely pathogenic, VUS per ACMG/AMP guidelines) > Search first: ClinVar, ClinGen, ACMG/AMP guidelines, VarSome
  • Variant type/class (missense, frameshift, nonsense, splice-site, structural)
  • Allele frequency in population databases > Search first: gnomAD, 1000 Genomes, ExAC, TOPMed, dbSNP
  • Somatic vs germline origin > Search first: COSMIC (somatic), ClinVar, ICGC, TCGA
  • Functional consequences (loss of function, gain of function, dominant negative)
  • Modifier Genes: Genes that modify disease severity or expression
  • Epigenetic Information: DNA methylation, histone modifications, chromatin changes affecting disease

    Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth

  • Chromosomal Abnormalities: Large-scale genetic changes (aneuploidy, translocations, inversions)

    Search first: DECIPHER, ClinVar, ECARUCA, UCSC Genome Browser

5. Environmental Information

  • Environmental Factors: Non-genetic contributing factors (toxins, radiation, pollution, occupational exposure)

    Search first: CTD (Comparative Toxicogenomics Database), TOXNET, PubMed, EPA databases

  • Lifestyle Factors: Behavioral factors (smoking, diet, exercise, alcohol consumption)

    Search first: CDC databases, WHO, PubMed, NHANES

  • Infectious Agents: If applicable, pathogens causing or triggering disease (bacteria, viruses, fungi, parasites)

    Search first: NCBI Taxonomy, ViPR, BV-BRC, MicrobeDB, GIDEON

6. Mechanism / Pathophysiology

Present this section as an ordered causal chain first, then the detail below. Open with a numbered sequence of mechanistic steps running from the initiating lesion (mutation, exposure, infection) to the clinical manifestation, one step per line, each naming what it causes next. State the causal verb explicitly ("leads to", "results in") and say where a step is inferred rather than demonstrated. Where the mechanism branches, show the branch. The categories below are a checklist of what to cover within those steps, not the organizing structure — a step may draw on several of them, and a category may contribute to several steps.

  • Molecular Pathways: Specific signaling cascades or biochemical pathways involved (Wnt, MAPK, mTOR, PI3K-AKT, etc.)

    Search first: KEGG, Reactome, WikiPathways, PathBank, BioCyc

  • Cellular Processes: Cell-level mechanisms (apoptosis, autophagy, cell cycle dysregulation, inflammation, etc.)

    Search first: Gene Ontology (GO), Reactome, KEGG, PubMed

  • Protein Dysfunction: How protein structure or function is altered (misfolding, aggregation, loss of function, gain of function)

    Search first: UniProt, PDB (Protein Data Bank), InterPro, Pfam, AlphaFold

  • Metabolic Changes: Alterations in metabolic processes (energy metabolism, lipid metabolism, amino acid metabolism)

    Search first: KEGG, BioCyc, HMDB (Human Metabolome Database), BRENDA

  • Immune System Involvement: Role of immune response (autoimmunity, immunodeficiency, chronic inflammation)

    Search first: ImmPort, Immunome Database, IEDB, Gene Ontology

  • Tissue Damage Mechanisms: How tissues/ are injured (oxidative stress, ischemia, fibrosis, necrosis)

    Search first: PubMed, Gene Ontology, Reactome

  • Biochemical Abnormalities: Specific molecular defects (enzyme deficiencies, receptor dysfunction, ion channel defects)

    Search first: BRENDA, UniProt, KEGG, OMIM, PubMed

  • Epigenetic Changes: DNA methylation, histone modifications affecting gene expression in disease

    Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth

  • Molecular Profiling (if available):
  • Transcriptomics/gene expression changes > Search first: GEO (Gene Expression Omnibus), ArrayExpress, GTEx, Human Cell Atlas, SRA
  • Proteomics findings > Search first: PRIDE, ProteomeXchange, Human Protein Atlas, STRING, BioGRID
  • Metabolomics signatures > Search first: MetaboLights, Metabolomics Workbench, HMDB, METLIN
  • Lipidomics alterations > Search first: LIPID MAPS, SwissLipids, LipidHome, Metabolomics Workbench
  • Genomic structural features > Search first: UCSC Genome Browser, Ensembl, NCBI, dbVar, DGV
  • Advanced Technologies (if applicable):
  • Single-cell analysis findings (cell-type specific mechanisms, cellular heterogeneity) > Search first: Human Cell Atlas, Single Cell Portal, GEO, CELLxGENE
  • Spatial transcriptomics findings > Search first: GEO, Spatial Research, Vizgen, 10x Genomics data
  • Multi-omics integration results > Search first: TCGA, ICGC, cBioPortal, LinkedOmics, PubMed
  • Functional genomics screens (CRISPR, RNAi) > Search first: DepMap, GenomeRNAi, PubMed, BioGRID ORCS

For each mechanism, describe: - The causal chain from initial trigger to clinical manifestation - Which mechanisms are upstream vs downstream - What cell types and biological processes are involved - Suggest GO terms for biological processes and CL terms for cell types

7. Anatomical Structures Affected

  • Organ Level:
  • Primary organs directly affected
  • Secondary organ involvement (complications, secondary effects)
  • Body systems involved (cardiovascular, nervous, digestive, respiratory, endocrine, etc.)

    Search first: Uberon, FMA (Foundational Model of Anatomy), OMIM, HPO, ICD-11, MeSH, SNOMED CT

  • Tissue and Cell Level:
  • Specific tissue types affected (epithelial, connective, muscle, nervous)
  • Specific cell populations targeted (with Cell Ontology terms)

    Search first: Uberon, Human Protein Atlas, Cell Ontology, Human Cell Atlas, CellMarker, PanglaoDB

  • Subcellular Level:
  • Cellular compartments involved (mitochondria, nucleus, ER, lysosomes) (with GO Cellular Component terms)

    Search first: Gene Ontology (Cellular Component), UniProt, Human Protein Atlas

  • Localization:
  • Specific anatomical sites (with UBERON terms) > Search first: FMA, Uberon, NeuroNames (for brain), SNOMED CT
  • Lateralization (unilateral, bilateral, asymmetric) > Search first: HPO, clinical literature, imaging databases

8. Temporal Development

  • Onset:
  • Typical age of onset (congenital, pediatric, adult, geriatric)
  • Onset pattern (acute, subacute, chronic, insidious)

    Search first: OMIM, Orphanet, HPO, PubMed

  • Progression:
  • Disease stages (early, intermediate, advanced, end-stage) > Search first: Cancer Staging Manual (AJCC), WHO classifications, PubMed
  • Progression rate (rapid, slow, variable)
  • Disease course pattern (episodic, relapsing-remitting, progressive, stable)
  • Disease duration (self-limited, chronic lifelong)

    Search first: Disease registries, longitudinal cohort databases, natural history studies, PubMed, Orphanet, OMIM

  • Patterns:
  • Remission patterns (spontaneous, treatment-induced) > Search first: Clinical trial databases, disease registries, PubMed
  • Critical periods (time windows of vulnerability or opportunity for intervention) > Search first: PubMed, developmental biology databases, clinical guidelines

9. Inheritance and Population

  • Epidemiology:
  • Prevalence (cases per 100,000 at given time)
  • Incidence (new cases per 100,000 per year)

    Search first: Orphanet, CDC, WHO, GBD (Global Burden of Disease), national registries, SEER, disease registries

  • For Genetic Etiology:
  • Inheritance pattern (AD, AR, X-linked, mitochondrial, multifactorial, polygenic) > Search first: OMIM, Orphanet, ClinVar, GTR (Genetic Testing Registry)
  • Penetrance (complete, incomplete, age-dependent) > Search first: ClinVar, OMIM, PubMed, ClinGen
  • Expressivity (variable, consistent) > Search first: OMIM, ClinVar, PubMed
  • Genetic anticipation (increasing severity in successive generations) > Search first: OMIM, PubMed (especially for repeat expansion disorders)
  • Germline mosaicism > Search first: ClinVar, OMIM, genetic counseling literature, PubMed
  • Founder effects (population-specific mutations) > Search first: gnomAD, population genetics databases, PubMed
  • Consanguinity role > Search first: OMIM, population studies, genetic counseling resources
  • Carrier frequency > Search first: gnomAD, carrier screening databases, GeneReviews, GTR
  • Population Demographics:
  • Affected populations (ethnic or demographic groups with higher prevalence) > Search first: gnomAD, 1000 Genomes, PAGE Study, PubMed, population registries
  • Geographic distribution (endemic areas, regional variation) > Search first: WHO, CDC, GBD, Orphanet, geographic epidemiology databases
  • Geographic distribution of specific variants
  • Sex ratio (male:female) > Search first: Disease registries, OMIM, PubMed, epidemiological databases
  • Age distribution of affected individuals > Search first: CDC, disease registries, SEER, Orphanet

10. Diagnostics

  • Clinical Tests:
  • Laboratory tests (blood, urine, tissue chemistry, specific enzyme assays) > Search first: LOINC, LabTests Online, PubMed
  • Biomarkers (proteins, metabolites, genetic markers, circulating biomarkers) > Search first: FDA Biomarker List, BEST (Biomarkers, EndpointS, and other Tools), PubMed
  • Imaging studies (X-ray, CT, MRI, PET, ultrasound) > Search first: RadLex, DICOM, Radiopaedia, imaging databases
  • Functional tests (pulmonary function, cardiac stress tests) > Search first: LOINC, clinical guidelines, PubMed
  • Electrophysiology (EEG, EMG, ECG, nerve conduction studies) > Search first: LOINC, clinical neurophysiology databases, PubMed
  • Biopsy findings (histopathology, immunohistochemistry) > Search first: SNOMED CT, College of American Pathologists resources, PubMed
  • Pathology findings (microscopic examination) > Search first: SNOMED CT, Digital Pathology databases, PubMed
  • Genetic Testing:

    Search first: GTR (Genetic Testing Registry), GeneReviews, ClinGen

  • Overview of recommended genetic testing approach
  • Whole genome sequencing (WGS) utility > Search first: GTR, ClinVar, GEL (Genomics England), gnomAD
  • Whole exome sequencing (WES) utility > Search first: GTR, ClinVar, OMIM, GeneMatcher
  • Gene panels (which panels, which genes) > Search first: GTR, ClinVar, laboratory-specific databases
  • Single gene testing > Search first: GTR, ClinVar, OMIM, GeneReviews
  • Chromosomal microarray (CMA) > Search first: DECIPHER, ClinVar, dbVar, ECARUCA
  • Karyotyping > Search first: Chromosome Abnormality Database, ClinVar, cytogenetics resources
  • FISH > Search first: ClinVar, cytogenetics databases, PubMed
  • Mitochondrial DNA testing > Search first: MITOMAP, MSeqDR, ClinVar, GTR
  • Repeat expansion testing > Search first: GTR, ClinVar, repeat expansion databases, PubMed
  • Omics-Based Diagnostics (if applicable):
  • RNA sequencing / transcriptomics > Search first: GEO, ArrayExpress, GTEx, RNA-seq databases
  • Proteomics > Search first: PRIDE, ProteomeXchange, FDA Biomarker database
  • Metabolomics > Search first: MetaboLights, Metabolomics Workbench, HMDB
  • Epigenomics > Search first: GEO, ENCODE, Roadmap Epigenomics, MethBase
  • Liquid biopsy > Search first: COSMIC, ClinVar, liquid biopsy databases, PubMed
  • Clinical Criteria:
  • Standardized diagnostic criteria (DSM, ICD, society guidelines) > Search first: DSM-5, ICD-11, clinical society guidelines, UpToDate
  • Differential diagnosis (other conditions to rule out, with distinguishing features) > Search first: DynaMed, UpToDate, clinical decision support systems
  • Screening:
  • Screening methods for asymptomatic individuals (newborn screening, carrier screening, cascade screening) > Search first: ACMG recommendations, CDC newborn screening, GTR

11. Outcome/Prognosis

  • Survival and Mortality:
  • Survival rate (5-year, 10-year, overall) > Search first: SEER, cancer registries, disease-specific registries, PubMed
  • Life expectancy (with and without treatment if applicable) > Search first: Orphanet, disease registries, actuarial databases, PubMed
  • Mortality rate > Search first: CDC, WHO, GBD, national mortality databases
  • Disease-specific mortality (deaths directly attributable to disease) > Search first: Disease registries, CDC Wonder, GBD, PubMed
  • Morbidity and Function:
  • Morbidity (disease-related disability and health impacts) > Search first: GBD, WHO, disability databases, PubMed
  • Disability outcomes (long-term functional impairments) > Search first: ICF (International Classification of Functioning), disability registries
  • Quality of life measures (EQ-5D, SF-36, PROMIS, disease-specific tools) > Search first: EQ-5D database, SF-36, PROMIS, PubMed
  • Disease Course:
  • Complications (secondary problems: infections, organ failure, etc.) > Search first: ICD codes, disease registries, clinical databases, PubMed
  • Recovery potential (likelihood and extent of recovery, with vs without treatment) > Search first: Natural history studies, rehabilitation databases, PubMed
  • Prediction:
  • Prognostic factors (age, disease severity, biomarkers, treatment response) > Search first: Prognostic models databases, clinical calculators, PubMed
  • Prognostic biomarkers (molecular markers predicting disease course) > Search first: FDA Biomarker database, PubMed, cancer prognostic databases

12. Treatment

  • Pharmacotherapy:
  • Pharmacological treatments (drug names, drug classes, mechanisms of action) > Search first: DrugBank, RxNorm, ATC classification, DailyMed, FDA databases
  • Pharmacogenomics (how genetic variants affect drug metabolism, efficacy, toxicity) > Search first: PharmGKB, CPIC (Clinical Pharmacogenetics), FDA Table of PGx Biomarkers
  • Advanced Therapeutics:
  • Gene therapy (viral vectors, CRISPR, gene replacement, gene editing) > Search first: ClinicalTrials.gov, FDA gene therapy database, ASGCT resources
  • Cell therapy (stem cell transplant, CAR-T, cellular therapeutics) > Search first: ClinicalTrials.gov, FDA cell therapy database, FACT standards
  • RNA-based therapies (ASOs, siRNA, mRNA therapies) > Search first: ClinicalTrials.gov, FDA approvals, PubMed
  • Targeted therapies (treatments directed at specific molecular targets) > Search first: My Cancer Genome, OncoKB, ClinicalTrials.gov, FDA approvals
  • Immunotherapies (checkpoint inhibitors, monoclonal antibodies) > Search first: Cancer Immunotherapy Database, FDA approvals, ClinicalTrials.gov
  • Surgical and Interventional:
  • Surgical interventions (types of surgery, timing, outcomes) > Search first: CPT codes, surgical registries, clinical guidelines, PubMed
  • Supportive and Rehabilitative:
  • Supportive care (symptom management, pain control, nutrition) > Search first: Clinical guidelines, Cochrane Library, PubMed
  • Rehabilitation (physical therapy, occupational therapy, speech therapy) > Search first: Rehabilitation medicine databases, clinical guidelines, PubMed
  • Experimental:
  • Experimental treatments in clinical trials (with NCT identifiers if available) > Search first: ClinicalTrials.gov, EU Clinical Trials Register, WHO ICTRP
  • Treatment Outcomes:
  • Treatment response rates > Search first: Clinical trial databases, FDA reviews, systematic reviews, PubMed
  • Side effects and adverse events > Search first: FDA Adverse Event Reporting System (FAERS), MedWatch, PubMed
  • Treatment Strategy:
  • Treatment algorithms (clinical pathways, decision trees) > Search first: Clinical practice guidelines, NCCN Guidelines, UpToDate
  • Combination therapies > Search first: ClinicalTrials.gov, treatment guidelines, PubMed
  • Personalized medicine approaches (genotype-guided treatment) > Search first: My Cancer Genome, CIViC, PharmGKB, precision medicine databases

For each treatment, suggest NCIT (NCI Thesaurus) clinical-intervention terms where applicable.

13. Prevention

  • Prevention Levels:
  • Primary prevention (preventing disease occurrence: vaccination, risk factor modification) > Search first: CDC, WHO, USPSTF recommendations, Cochrane Library
  • Secondary prevention (early detection and treatment: screening programs, early intervention) > Search first: USPSTF, CDC screening guidelines, WHO
  • Tertiary prevention (preventing complications in those with disease) > Search first: Clinical guidelines, disease management protocols, PubMed
  • Immunization: Vaccine strategies (if applicable)

    Search first: CDC vaccine schedules, WHO immunization, FDA vaccine database

  • Screening and Early Detection:
  • Screening programs (population-based: newborn screening, cancer screening) > Search first: CDC screening programs, USPSTF, cancer screening databases
  • Genetic screening (carrier screening, preimplantation genetic diagnosis, prenatal testing) > Search first: ACMG recommendations, ACOG guidelines, GTR
  • Risk stratification (identifying high-risk individuals for targeted prevention) > Search first: Risk prediction models, clinical calculators, PubMed
  • Behavioral Interventions: Lifestyle modifications to reduce risk

    Search first: CDC, WHO, behavioral intervention databases, Cochrane Library

  • Counseling: Genetic counseling (risk assessment, family planning guidance)

    Search first: NSGC resources, ACMG guidelines, GeneReviews

  • Public Health:
  • Public health interventions (sanitation, vector control, health education) > Search first: CDC, WHO, public health databases, PubMed
  • Environmental interventions (reducing environmental risk factors) > Search first: EPA databases, WHO environmental health, PubMed
  • Prophylaxis: Preventive medications or procedures

    Search first: Clinical guidelines, FDA approvals, PubMed

14. Other Species / Natural Disease

  • Taxonomy: Species affected (with NCBI Taxon identifiers)

    Search first: NCBI Taxonomy

  • Breed: Specific breeds affected (with VBO identifiers if applicable)

    Search first: VBO (Vertebrate Breed Ontology)

  • Gene: Orthologous genes in other species (with NCBI Gene IDs)

    Search first: NCBI Gene

  • Natural Disease:
  • Naturally occurring disease in other species (companion animals, wildlife) > Search first: OMIA (Online Mendelian Inheritance in Animals), VetCompass, PubMed
  • Veterinary relevance and importance in animal health > Search first: OMIA, veterinary databases, PubMed
  • Comparative Biology:
  • Comparative pathology (similarities and differences across species) > Search first: OMIA, comparative pathology databases, PubMed
  • Evolutionary conservation of disease mechanisms > Search first: HomoloGene, OrthoMCL, Alliance of Genome Resources
  • Transmission (if applicable):
  • Zoonotic potential > Search first: CDC zoonotic diseases, WHO zoonoses, GIDEON
  • Cross-species susceptibility > Search first: NCBI Taxonomy, veterinary databases, PubMed

15. Model Organisms

  • Model Types:
  • Model organism type (mammalian, invertebrate, cellular, in vitro) > Search first: Alliance of Genome Resources, model organism databases
  • Specific model systems (mouse, rat, zebrafish, Drosophila, C. elegans, yeast, cell lines, organoids, iPSCs) > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, SGD, ATCC, Cellosaurus
  • Induced models (drug treatment, surgical intervention, environmental manipulation) > Search first: MGI, model organism databases, PubMed
  • Genetic Models:
  • Types available (knockout, knock-in, transgenic, conditional, humanized) > Search first: MGI, IMPC, KOMP, EuMMCR, IMSR
  • Model Characteristics:
  • Phenotype recapitulation (how well model reproduces human disease features) > Search first: Model organism databases, comparative studies, PubMed
  • Model limitations (aspects of human disease not captured) > Search first: Model organism databases, PubMed, review articles
  • Applications:
  • Research applications (what aspects of disease can be studied) > Search first: Model organism databases, PubMed
  • Resources:
  • Model databases > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, IMSR, EMMA, MMRRC

Citation Requirements

  • Cite primary literature (PMID preferred) for all mechanistic and clinical claims
  • Prioritize recent reviews and landmark papers
  • Include direct quotes from abstracts where possible to support key statements
  • Distinguish evidence source types: human clinical, model organism, in vitro, computational

Output Format

Structure your response as a comprehensive narrative organized by the sections above. For each section, provide: - Factual content with specific details (numbers, percentages, gene names, variant nomenclature) - Ontology term suggestions (HPO, GO, CL, UBERON, CHEBI, NCIT, MONDO) where applicable - Evidence citations with PMIDs - Direct quotes from abstracts to support key claims - Clear indication when information is not available or not applicable for this disease

This report will be used to populate a disease knowledge base entry with: - Pathophysiology descriptions with causal chains - Gene/protein annotations (HGNC, GO terms) - Phenotype associations (HP terms) with frequencies - Cell type involvement (CL terms) - Anatomical locations (UBERON terms) - Chemical entities (CHEBI terms) - Treatment annotations (NCIT terms) - Evidence items with PMIDs and exact abstract quotes - Epidemiology, prognosis, diagnostic, and prevention information - Animal model descriptions with phenotype recapitulation details

Hereditary Hyperferritinemia–Cataract Syndrome (HHCS)

Executive summary

Hereditary hyperferritinemia–cataract syndrome (HHCS), also called hereditary hyperferritinemia with congenital cataracts, is a rare Mendelian disorder caused by germline noncoding variants in the iron-responsive element (IRE) of FTL, the ferritin light-chain gene. These variants impair post-transcriptional repression of FTL, causing iron-independent overproduction of L-ferritin. The defining phenotype is persistent, often marked hyperferritinemia without systemic iron overload, together with bilateral, usually early-onset and slowly progressive nuclear cataracts containing L-ferritin-rich deposits. The major clinical hazard is not systemic disease but misdiagnosis as hemochromatosis, followed by unnecessary liver biopsy, phlebotomy, or iron chelation. Cataract surgery is the only established phenotype-directed intervention; there is no treatment indication for the ferritin elevation itself. (moravikova2020hereditaryhyperferritinemiacataractsyndrome pages 1-7, eris2023hereditaryhyperferritinemiacataractsyndrome pages 4-5, piperno2023hereditaryhyperferritinemia pages 10-12)

The most useful knowledge-base summary is:

Knowledge-base field Evidence-supported summary Key sources
Disease / identifiers Hereditary hyperferritinemia-cataract syndrome (HHCS; OMIM #600886) is a rare Mendelian disorder characterized by persistent hyperferritinemia unrelated to body iron stores and early-onset bilateral cataracts. Piperno et al., 2023; Moravikova et al., 2020 (moravikova2020hereditaryhyperferritinemiacataractsyndrome pages 1-7, piperno2023hereditaryhyperferritinemia pages 10-12)
Causal gene / inheritance FTL (ferritin light-chain gene); usually heterozygous autosomal-dominant inheritance. De novo disease and rare homozygous affected individuals have been documented. Moravikova et al., 2020; Van de Sompele et al., 2017 (moravikova2020hereditaryhyperferritinemiacataractsyndrome pages 1-7, sompele2017functionalcharacterizationofa pages 2-3)
Molecular lesion Pathogenic noncoding substitutions, deletions, and insertion-deletions affect the iron-responsive element (IRE) in the FTL 5′ untranslated region, especially its upper stem, conserved hexaloop, and cytosine bulge. A 2019 review catalogued 36 point mutations, nine deletions, and two insertion-deletions associated with HHCS. Cadenas et al., 2019; Millonig et al., 2010 (millonig2010hyperferritinaemiacataractsyndromeworldwide pages 9-10, cadenas2019lferritinonegene pages 5-8)
Core mechanism IRE disruption reduces binding of iron-regulatory proteins IRP1/IRP2 and releases normal iron-dependent translational repression, causing constitutive excess L-ferritin synthesis. Functional EMSA evidence showed reduced IRP1 affinity for the c.-151A>G IRE. L-ferritin-rich deposits/crystals in the lens diffract light and produce cataract; absence of systemic iron excess distinguishes HHCS from hemochromatosis. Van de Sompele et al., 2017; Piperno et al., 2023 (piperno2023hereditaryhyperferritinemia pages 10-12, sompele2017functionalcharacterizationofa pages 8-9, sompele2017functionalcharacterizationofa pages 2-3)
Ferritin / iron laboratory pattern Persistent, often marked serum hyperferritinemia with normal serum iron, transferrin saturation, and body-iron stores. Reported serum ferritin is commonly about 700–2,000 µg/L; one seven-kindred series recorded minima of 740–1,960 µg/L (median 1,420 µg/L). Ferritin may fluctuate but did not increase with age in that series. Lachlan et al., 2004; Cosentino et al., 2016 (lachlan2004clinicalfeaturesand pages 1-2, cosentino2016hyperferritinemiacataractsyndromelongterm pages 1-6)
Ocular phenotype / onset Bilateral, generally symmetrical nuclear cataracts can be congenital or recognized in infancy, childhood, or later adulthood. Typical findings include punctate white “breadcrumb-like,” crystalline, sunflower-like, or radial opacities. Cataracts are usually slowly progressive; visual severity and age at surgery vary within and among families. In one British series, median diagnosis was five years and median extraction age was 25 years (range 22–42). Lachlan et al., 2004; Cosentino et al., 2016 (lachlan2004clinicalfeaturesand pages 3-4, lachlan2004clinicalfeaturesand pages 1-2, cosentino2016hyperferritinemiacataractsyndromelongterm pages 1-6)
Epidemiology Worldwide distribution; approximate prevalence 1:200,000, but this is an estimate rather than a population-registry measurement. A 2018 report noted approximately 160 known families/cases. No established sex bias is supported. Piperno et al., 2023; Ferro et al., 2018 (ferro2018ftlc.168g>cmutation pages 1-2, piperno2023hereditaryhyperferritinemia pages 10-12)
Diagnosis Suspect HHCS when isolated familial hyperferritinemia coexists with early bilateral cataracts and normal transferrin saturation. Evaluate blood count, serum iron, transferrin/TIBC, transferrin saturation, liver enzymes, and inflammatory causes; slit-lamp examination can reveal characteristic opacities. Confirm by sequencing the FTL 5′UTR/IRE and test relatives. Liver biopsy is generally unnecessary when iron overload has been excluded. Millonig et al., 2010; Moravikova et al., 2020 (moravikova2020hereditaryhyperferritinemiacataractsyndrome pages 1-7, millonig2010hyperferritinaemiacataractsyndromeworldwide pages 3-4)
Management Hyperferritinemia itself requires no iron-removal treatment. Avoid phlebotomy and iron chelation unless independent iron overload is proven; misdiagnosis has caused iron-deficiency anemia and, in one report, life-threatening hyperammonemia during deferasirox therapy. Monitor vision and perform standard cataract extraction with intraocular-lens management when visual function warrants it. Moravikova et al., 2020; Piperno et al., 2023 (moravikova2020hereditaryhyperferritinemiacataractsyndrome pages 1-7, eris2023hereditaryhyperferritinemiacataractsyndrome pages 4-5, piperno2023hereditaryhyperferritinemia pages 10-12)
Prognosis Life-threatening systemic disease or shortened survival has not been demonstrated. Morbidity is predominantly visual and usually amenable to cataract surgery. Serum hyperferritinemia is lifelong but is not, by itself, evidence of organ iron injury. Millonig et al., 2010; Piperno et al., 2023 (millonig2010hyperferritinaemiacataractsyndromeworldwide pages 3-4, piperno2023hereditaryhyperferritinemia pages 10-12)
Evidence gaps No robust incidence, sex-ratio, penetrance, quality-of-life, survival, or population carrier-frequency studies were identified. Genotype–phenotype prediction remains weak except that rare biallelic variants may be more severe. No HHCS-specific therapeutic trials, validated pharmacotherapy, gene/RNA therapy, direct disease animal model, or single-cell, spatial-transcriptomic, epigenomic, proteomic, metabolomic, or multi-omics study was found in the gathered evidence. Cadenas et al., 2019; Shiels, 2024 (sompele2017functionalcharacterizationofa pages 8-9, cadenas2019lferritinonegene pages 5-8, shiels2024throughthecatmapa pages 20-21, shiels2024throughthecatmap pages 19-21)

Table: Concise evidence table covering the defining clinical, molecular, diagnostic, management, and epidemiologic features of HHCS, together with major evidence gaps. Claims are restricted to the gathered literature and distinguish estimated figures from directly observed findings.

Evidence framework and limitations

Evidence consists chiefly of multigeneration human families, small case series, biochemical studies of mutant IRE–IRP binding, and reviews. HHCS is so rare that registry-quality incidence, penetrance, survival, quality-of-life, and treatment-response data are unavailable. The most current disease-focused synthesis retrieved was Piperno et al., published January 2023; a June 2024 cataract-genetics review places FTL within the contemporary inherited-cataract landscape but adds no HHCS-specific therapy or model. (piperno2023hereditaryhyperferritinemia pages 10-12, shiels2024throughthecatmap pages 3-4, shiels2024throughthecatmap pages 19-21)

PMIDs were not present in the retrieved full-text metadata and therefore are not supplied speculatively. DOI links and publication dates are provided. Short quotations below are limited to wording verifiable in retrieved abstracts.


1. Disease information

Definition

HHCS is an autosomal-dominant disorder characterized by persistent elevation of serum L-ferritin, normal body-iron stores and transferrin saturation, and bilateral congenital, juvenile, or presenile cataract. It should not be classified as hereditary hemochromatosis: the elevated ferritin reflects dysregulated ferritin synthesis rather than excess stored iron. (lachlan2004clinicalfeaturesand pages 1-2, millonig2010hyperferritinaemiacataractsyndromeworldwide pages 3-4, piperno2023hereditaryhyperferritinemia pages 10-12)

A landmark review defines it as follows: “The hereditary hyperferritinaemia-cataract syndrome (HHCS) is characterised by an autosomal dominant cataract and high levels of serum ferritin without iron overload.” Millonig et al., April 2010. (millonig2010hyperferritinaemiacataractsyndromeworldwide pages 3-4)

Identifiers and synonyms

  • MONDO: MONDO:0010952, as supplied in the request.
  • OMIM phenotype: 600886.
  • Causal gene: FTL, ferritin light polypeptide/ferritin light chain; chromosome 19.
  • Orphanet: commonly represented as hereditary hyperferritinemia–cataract syndrome; database releases should be checked before storing a numeric ORPHA identifier because identifiers were not visible in the retrieved source text.
  • ICD-10/ICD-11: no uniquely disease-specific code was verified. Operational coding generally requires separate cataract and abnormal-serum-enzyme/protein findings plus a rare-genetic-disease code where local systems permit.
  • MeSH: no dedicated HHCS descriptor was verified; likely indexing concepts include Cataract, Hyperferritinemia, Ferritins, and Genetic Diseases, Inborn.
  • Synonyms: hereditary hyperferritinemia-cataract syndrome; hereditary hyperferritinaemia-cataract syndrome; hyperferritinemia-cataract syndrome; hyperferritinaemia-cataract syndrome; HHCS; HCS; hereditary hyperferritinemia with congenital/early-onset cataract.

The report concerns aggregated disease-level literature and published patients/families, not individual EHR records.


2. Etiology, risk, protection, and environment

Primary cause

The cause is a germline FTL 5′-UTR IRE variant—usually a heterozygous substitution, deletion, or insertion-deletion. The altered RNA stem-loop has reduced affinity for iron-regulatory proteins, releasing the normal iron-sensitive block on translation. (moravikova2020hereditaryhyperferritinemiacataractsyndrome pages 1-7, millonig2010hyperferritinaemiacataractsyndromeworldwide pages 9-10, cadenas2019lferritinonegene pages 5-8)

A 2019 catalog reported 36 point mutations, nine deletions, and two insertion-deletions associated with HHCS. Examples include c.-161C>T, c.-167C>T, c.-168G>C, c.-151A>G, and c.-164_-158del7. Nomenclature varies historically because variants were numbered relative to the IRE rather than consistently by HGVS; clinical reports should normalize against NM_000146.3 or the current MANE transcript. (moravikova2020hereditaryhyperferritinemiacataractsyndrome pages 1-7, sompele2017functionalcharacterizationofa pages 2-3, cadenas2019lferritinonegene pages 3-5, cadenas2019lferritinonegene pages 5-8)

Risk factors

  • Genetic: carrying a pathogenic FTL IRE allele is the principal risk factor. Family history is strongly informative, but a confirmed de novo c.-167C>T case shows that a negative family history does not exclude HHCS. (moravikova2020hereditaryhyperferritinemiacataractsyndrome pages 1-7)
  • Family history: each child of a heterozygous affected person has a theoretical 50% transmission probability.
  • Biallelic state: exceptionally, homozygous IRE variants occur. In the c.-151A>G family, the homozygous proband was more severely affected than heterozygous relatives, supporting a dosage effect for at least some alleles. This is not a general penetrance estimate. (sompele2017functionalcharacterizationofa pages 8-9, sompele2017functionalcharacterizationofa pages 2-3)
  • Sex, ancestry, age: no causal sex or ancestry bias is established. Age affects cataract recognition and visual impact, not the existence of the germline lesion.

Protective factors and modifiers

No validated protective allele, modifier gene, diet, drug, or lifestyle intervention has been shown to prevent HHCS. Intrafamilial variability indicates that modifiers probably exist, but none is established. Ferritin level and cataract severity do not show a reliable one-to-one relationship. (lachlan2004clinicalfeaturesand pages 1-2, piperno2023hereditaryhyperferritinemia pages 10-12)

Gene–environment interaction

No disease-specific gene–environment interaction has been demonstrated. Inflammation, alcohol use, metabolic syndrome, malignancy, infection, and liver disease can independently raise ferritin and obscure the characteristic biochemical pattern, but they do not cause the inherited syndrome. Coexisting iron deficiency or true iron overload can occur independently and must be assessed on its own evidence. (eris2023hereditaryhyperferritinemiacataractsyndrome pages 4-5, millonig2010hyperferritinaemiacataractsyndromeworldwide pages 3-4)

There is no infectious cause, toxin-associated cause, occupational risk, or zoonotic component.


3. Phenotypes

Core phenotype table

Phenotype Type and course Frequency/evidence Suggested HPO term
Hyperferritinemia Laboratory abnormality; usually lifelong, persistent but quantitatively fluctuating Defining biochemical feature; commonly about 700–2,000 µg/L. Seven British kindreds had minimum recorded values 740–1,960 µg/L, median 1,420 µg/L Hyperferritinemia (HP:0003281; verify current release)
Bilateral nuclear cataract Clinical sign/structural ocular phenotype; congenital, infantile, childhood, or presenile; usually slowly progressive Defining clinical manifestation, although timing and severity vary Cataract (HP:0000518); Congenital cataract; Nuclear cataract
Punctate/crystalline lens opacities Slit-lamp sign: breadcrumb-like, pulverulent, sunflower/radial, peripheral flecks or crystalline inclusions Highly characteristic but morphology is not invariant Lens opacity / cataract morphology terms
Reduced visual acuity Functional consequence; ranges from mild to surgery-requiring Four young members in one family had acuity below 20/40; many remain mildly affected for years Reduced visual acuity (HP:0007663)
Normal transferrin saturation/body iron Negative diagnostic feature Typical and central to distinction from hemochromatosis Use laboratory annotation rather than a disease HPO term

(lachlan2004clinicalfeaturesand pages 3-4, lachlan2004clinicalfeaturesand pages 1-2, cosentino2016hyperferritinemiacataractsyndromelongterm pages 1-6, ferro2018ftlc.168g>cmutation pages 1-2)

Cataract onset, severity, and progression

In seven British kindreds, cataract was diagnosed at a median age of five years; most affected people eventually underwent extraction at a median age of 25 years (range 22–42). Infant lenses could show sparse posterior breadcrumb-like opacities, adolescent lenses sunflower-like radial opacities, and extracted lenses crystalline inclusions immunoreactive for L-ferritin. Severity varied substantially within and between families. (lachlan2004clinicalfeaturesand pages 3-4, lachlan2004clinicalfeaturesand pages 1-2)

Long-term observations in an Italian family found limited progression over approximately 18 years, supporting a generally slow adult course. Other families show progressive visual impairment requiring surgery, so “slowly progressive and variable” is more accurate than “stable.” (cosentino2016hyperferritinemiacataractsyndromelongterm pages 1-6, ferro2018ftlc.168g>cmutation pages 1-2)

Quality of life

No HHCS-specific EQ-5D, SF-36, PROMIS, utility, educational, or employment study was identified. The principal impact is visual: glare, blur, impaired reading/driving or school performance, and—if dense cataract obstructs vision during early childhood—risk of deprivation amblyopia. General congenital-cataract guidance emphasizes early optical rehabilitation in visually significant infantile disease. (shiels2024throughthecatmap pages 3-4, shiels2024throughthecatmapa pages 4-5)

No reproducible behavioral, neurologic, hepatic, endocrine, cardiac, or inflammatory syndrome belongs to classic HHCS. Neurologic manifestations should prompt assessment for other FTL allelic disorders, especially neuroferritinopathy, or a second diagnosis. (cadenas2019lferritinonegene pages 1-3, cadenas2019lferritinonegene pages 5-8)


4. Genetic and molecular information

Gene and protein

  • Gene: FTL, ferritin light chain.
  • Product: L-ferritin, one of the subunits forming the 24-mer ferritin shell.
  • Disease mechanism: regulatory gain of expression—not protein-coding loss of function and not a classic dominant-negative effect.
  • Origin: constitutional/germline. Somatic FTL variants are not the recognized cause.

Serum ferritin is largely L-ferritin-rich, relatively iron-poor material; in HHCS, constitutive synthesis yields excess L-rich ferritin, including H0-L24 homopolymers. (piperno2023hereditaryhyperferritinemia pages 10-12, cadenas2019lferritinonegene pages 1-3)

Variant spectrum and classification

Pathogenic HHCS variants cluster in structurally critical portions of the IRE: the conserved CAGUGX hexaloop, upper stem, and cytosine bulge. They include single-nucleotide substitutions and short indels. Examples with human segregation evidence include:

  • c.-161C>T, c.-167C>T, c.-168G>C;
  • c.-151A>G (“Ghent +49A>G”);
  • c.-164_-158del7 (“Esplugues +36_42del7”);
  • older reports using IRE-relative descriptions such as +32G>T or +32G>C. (moravikova2020hereditaryhyperferritinemiacataractsyndrome pages 1-7, ferro2018ftlc.168g>cmutation pages 1-2, millonig2010hyperferritinaemiacataractsyndromeworldwide pages 9-10, sompele2017functionalcharacterizationofa pages 2-3, cadenas2019lferritinonegene pages 3-5)

The c.-151A>G functional study used RNA-structure prediction and EMSA. Mutant RNA retained IRP1 binding but showed a greater than fivefold impairment in apparent affinity relative to wild type, demonstrating that partial—not only complete—loss of repression can cause disease. (sompele2017functionalcharacterizationofa pages 8-9, sompele2017functionalcharacterizationof pages 8-9)

ClinVar classifications must be retrieved variant by variant and transcript-normalized. Many classic alleles have strong pathogenic evidence from segregation, characteristic phenotype, rarity, critical RNA location, and functional assays, but the report should not automatically label every IRE variant pathogenic.

Population frequency

Pathogenic alleles are expected to be extremely rare. Variant-specific gnomAD/TOPMed frequencies were not available in the retrieved evidence and must be queried using normalized genomic coordinates. No reliable carrier-frequency estimate exists.

Modifiers, epigenetics, and chromosomal abnormalities

No validated modifier gene, disease-associated methylation signature, histone/chromatin abnormality, large deletion, translocation, inversion, aneuploidy, or recurrent structural variant has been established. HHCS is ordinarily a small noncoding sequence disorder.


5. Environmental and lifestyle information

Environmental exposure, diet, smoking, exercise, alcohol, radiation, pollution, and infectious agents are not established contributors to HHCS initiation. These factors may cause other cataracts or alter serum ferritin independently and therefore complicate diagnosis. Iron intake does not correct or normalize the regulatory defect, and a high ferritin value alone is not a reason to restrict dietary iron. Conversely, documented iron deficiency should not be left untreated merely because serum ferritin is high in HHCS; iron status must be assessed using transferrin saturation, hemoglobin, red-cell indices, and the broader clinical context. (eris2023hereditaryhyperferritinemiacataractsyndrome pages 4-5, millonig2010hyperferritinaemiacataractsyndromeworldwide pages 3-4)


6. Mechanism and pathophysiology

Ordered causal chain

  1. A germline FTL 5′-UTR IRE substitution or indel leads to distortion or destabilization of the IRE RNA stem-loop. (millonig2010hyperferritinaemiacataractsyndromeworldwide pages 9-10, cadenas2019lferritinonegene pages 5-8)
  2. The altered IRE leads to reduced binding/functional repression by IRP1 and IRP2; reduced IRP1 affinity has been demonstrated directly for selected variants by EMSA. (sompele2017functionalcharacterizationofa pages 8-9, sompele2017functionalcharacterizationof pages 8-9)
  3. Loss of iron-sensitive repression results in constitutive FTL translation even when cytosolic iron is low or normal. (lachlan2004clinicalfeaturesand pages 1-2, piperno2023hereditaryhyperferritinemia pages 10-12)
  4. Constitutive translation leads to excess L-ferritin-rich apoferritin within cells and elevated circulating ferritin that is uncoupled from body-iron stores. (lachlan2004clinicalfeaturesand pages 1-2, piperno2023hereditaryhyperferritinemia pages 10-12)
  5. In the lens, excess L-ferritin results in intracellular L-ferritin-rich deposits/crystalline aggregates; this tissue-selective accumulation is demonstrated histologically, while the precise basis of lens selectivity remains incompletely resolved. (lachlan2004clinicalfeaturesand pages 3-4, piperno2023hereditaryhyperferritinemia pages 10-12)
  6. Lens deposits lead to refractive-index discontinuities and light diffraction/scattering—an accepted but partly inferred physical mechanism—which results in punctate, crystalline, pulverulent, or sunflower-like opacities. (lachlan2004clinicalfeaturesand pages 3-4, piperno2023hereditaryhyperferritinemia pages 10-12)
  7. Progressive accumulation leads to bilateral nuclear cataract and, when sufficiently dense, reduced visual acuity and need for cataract extraction. (lachlan2004clinicalfeaturesand pages 3-4, cosentino2016hyperferritinemiacataractsyndromelongterm pages 1-6)
  8. Parallel branch: excess circulating ferritin without increased transferrin saturation does not result in hemochromatotic organ iron deposition; treating the ferritin number with venesection instead leads to iatrogenic iron deficiency. (eris2023hereditaryhyperferritinemiacataractsyndrome pages 4-5, millonig2010hyperferritinaemiacataractsyndromeworldwide pages 3-4)

Pathway and process interpretation

This is primarily an IRE–IRP post-transcriptional iron-homeostasis disorder, not a canonical Wnt, MAPK, mTOR, PI3K–AKT, hepcidin–ferroportin, immune, or inflammatory disease. Upstream events are RNA structural change and impaired translational repression; downstream events are L-ferritin overexpression, aggregation/deposition, optical scattering, and cataract.

An additional 2019 mechanistic study identified human eIF3 as a distinct repressor of FTL translation and showed that some hyperferritinemia-associated 5′-UTR variants can disrupt eIF3-mediated repression. This broadens current understanding of FTL translational control, although the gathered evidence does not establish eIF3 disruption for every clinically pathogenic HHCS allele.

Suggested ontology annotations

  • GO biological process: cellular iron-ion homeostasis; iron-ion storage; regulation of translation; negative regulation of translation; response to iron ion; protein complex assembly.
  • GO molecular function: ferric-iron binding; ferroxidase-associated ferritin complex functions; RNA binding for IRP1/IRP2; translation-regulator activity.
  • GO cellular component: ferritin complex; cytosol; extracellular region/serum; lens fiber-cell cytoplasm.
  • Cell Ontology: lens epithelial cell; lens fiber cell; hepatocyte and macrophage may contribute serum ferritin biology, but their HHCS-specific contribution has not been resolved.
  • CHEBI: iron(2+), iron(3+), ferric iron; identifiers should be validated against the production ontology release.

No HHCS-specific immune activation, apoptosis signature, mitochondrial defect, lipidopathy, or systemic oxidative-injury phenotype is established.

Molecular profiling and advanced technologies

No HHCS-specific single-cell RNA-seq, spatial transcriptomics, comprehensive proteomics, metabolomics, lipidomics, epigenomics, multi-omics integration, organoid study, or CRISPR/RNAi screen was identified. Lens immunoreactivity for L-ferritin and IRE-binding assays are the principal molecular-level evidence. (lachlan2004clinicalfeaturesand pages 3-4, shiels2024throughthecatmapa pages 20-21, shiels2024throughthecatmap pages 19-21)


7. Anatomical structures affected

Organ and tissue level

The directly affected organ is the eye, specifically the crystalline lens, usually bilaterally and relatively symmetrically. Opacities frequently involve the embryonic/fetal nucleus and may extend centrifugally into cortical regions. No secondary systemic organ damage is expected from classic HHCS itself. (lachlan2004clinicalfeaturesand pages 3-4, ferro2018ftlc.168g>cmutation pages 1-2)

Suggested terms:

  • UBERON: eye; lens of eye; lens epithelium; lens fiber; lens nucleus—validate exact identifiers in the current Uberon release.
  • HPO: bilateral cataract; congenital cataract; juvenile cataract; nuclear cataract; reduced visual acuity.
  • CL: lens epithelial cell; lens fiber cell.
  • GO cellular component: cytosol and ferritin complex.

At the subcellular level, the key lesion is excess cytosolic L-ferritin and formation of high-molecular-weight/crystalline deposits. A primary nuclear-genome mutation is present, but the pathogenic deposits are not a nuclear-organelle lesion.


8. Temporal development

Serum hyperferritinemia is constitutional and likely present from early life, although it is often discovered incidentally during anemia evaluation, pregnancy screening, or family testing. Cataracts can be congenital or first recognized in infancy, childhood, adolescence, or adulthood. The 2023 synthesis places reported presentation approximately between ages 1 and 45 years. (lachlan2004clinicalfeaturesand pages 1-2, piperno2023hereditaryhyperferritinemia pages 10-12)

There is no formal staging system. A useful clinical sequence is:

  1. asymptomatic hyperferritinemia and subtle punctate lens deposits;
  2. slowly increasing nuclear/cortical opacities;
  3. functional visual impairment;
  4. cataract extraction when indicated.

The disorder is lifelong, generally chronic, and slowly progressive rather than episodic or relapsing. Cataracts do not spontaneously remit. Surgery removes the opaque lens, whereas serum hyperferritinemia persists. Dense infantile cataract represents the critical period because delayed optical correction risks irreversible amblyopia; milder adult disease can be monitored according to function. (lachlan2004clinicalfeaturesand pages 3-4, cosentino2016hyperferritinemiacataractsyndromelongterm pages 1-6, shiels2024throughthecatmap pages 3-4)


9. Inheritance and population

HHCS is predominantly autosomal dominant. Penetrance of biochemical hyperferritinemia appears high in reported mutation-positive families, but ascertainment is strong and no unbiased numerical estimate is available. Cataract expressivity and age at recognition are variable. No genetic anticipation has been demonstrated. Germline mosaicism is theoretically possible but not established as a recurrent phenomenon. (moravikova2020hereditaryhyperferritinemiacataractsyndrome pages 1-7, lachlan2004clinicalfeaturesand pages 1-2)

The best available prevalence estimate is approximately 1 per 200,000, worldwide, but this is not based on population-wide screening. A 2018 report cited roughly 160 known families/cases, indicating substantial under-recognition is plausible. Incidence, carrier frequency, and sex ratio are unknown. (ferro2018ftlc.168g>cmutation pages 1-2, piperno2023hereditaryhyperferritinemia pages 10-12)

Affected families have been reported across Europe, Asia, and the Americas and among multiple ancestries. No established ethnic restriction exists. Recurrent alleles may reflect mutationally sensitive IRE positions rather than a single universal founder. Consanguinity is not generally relevant to this dominant disease, although it enabled homozygosity in the c.-151A>G family. (sompele2017functionalcharacterizationofa pages 2-3)


10. Diagnostics

Practical diagnostic algorithm

  1. Confirm ferritin elevation and review age- and sex-appropriate laboratory reference ranges.
  2. Measure serum iron, transferrin/TIBC, transferrin saturation, complete blood count, reticulocyte indices as appropriate, CRP/ESR, and liver enzymes.
  3. Exclude common acquired causes: inflammation/infection, metabolic liver disease, alcohol-related disease, malignancy, liver injury, and iron supplementation.
  4. Determine whether true iron overload is present. Normal transferrin saturation and absent organ iron loading strongly favor HHCS when cataract is present.
  5. Obtain a three-generation history of cataracts, high ferritin, phlebotomy, anemia, and liver disease.
  6. Perform slit-lamp examination, looking for bilateral punctate breadcrumb-like, pulverulent, crystalline, sunflower/radial, or nuclear opacities.
  7. Confirm by sequencing the FTL 5′UTR IRE, with deletion/indel-sensitive analysis and transcript-normalized interpretation.
  8. Offer targeted testing and ophthalmic evaluation to relatives. (moravikova2020hereditaryhyperferritinemiacataractsyndrome pages 1-7, eris2023hereditaryhyperferritinemiacataractsyndrome pages 4-5, millonig2010hyperferritinaemiacataractsyndromeworldwide pages 3-4)

Genetic-testing modalities

  • Preferred: targeted Sanger or high-depth NGS of the FTL 5′UTR/IRE when the phenotype is characteristic.
  • Cataract/iron-disorder panels: useful if the phenotype is atypical; the panel must cover the noncoding FTL IRE, since coding-only designs may miss HHCS.
  • WES: may be useful for heterogeneous inherited cataract but can inadequately capture or filter the relevant 5′UTR. A 2024 review reports 50–90% molecular diagnosis for genetic pediatric cataract using modern panels/high-throughput sequencing overall, not specifically HHCS. (shiels2024throughthecatmapa pages 20-21, shiels2024throughthecatmap pages 19-21)
  • WGS: potentially useful if targeted testing is negative, particularly for noncoding or structural lesions, but no HHCS-specific diagnostic-yield study was identified.
  • CMA, karyotype, FISH, mitochondrial sequencing, and repeat-expansion testing: not routine for classic HHCS.
  • RNA-seq/proteomics/metabolomics/epigenomics/liquid biopsy: no validated diagnostic role.

Imaging, biopsy, and pathology

MRI-based liver iron assessment may be used when biochemical or clinical findings genuinely suggest coincident iron overload. Routine liver biopsy is inappropriate merely for high ferritin in a characteristic HHCS case. Extracted lenses can contain crystalline, immunoreactive L-ferritin inclusions, but lens biopsy is not a diagnostic requirement. (lachlan2004clinicalfeaturesand pages 3-4, millonig2010hyperferritinaemiacataractsyndromeworldwide pages 3-4)

Differential diagnosis

  • HFE or non-HFE hemochromatosis: typically increased transferrin saturation and evidence of iron loading; cataract morphology is not characteristic.
  • Ferroportin disease: hyperferritinemia may coexist with normal/low transferrin saturation but tissue iron is increased.
  • Inflammatory, infectious, malignant, hepatic, alcohol-related, or metabolic hyperferritinemia: distinguished by clinical context and inflammatory/liver findings.
  • Benign FTL-related hyperferritinemia: high ferritin without cataract, associated with a different FTL variant class.
  • Neuroferritinopathy: coding FTL variants, movement/cognitive disorder and basal-ganglia iron accumulation, often low or normal serum ferritin rather than classic HHCS.
  • Other inherited cataracts: crystallin, connexin, transcription-factor, metabolic, infectious, traumatic, steroid, or radiation-associated cataracts; serum ferritin pattern distinguishes HHCS. (cadenas2019lferritinonegene pages 1-3, cadenas2019lferritinonegene pages 5-8, shiels2024throughthecatmap pages 3-4)

There are no universally adopted society diagnostic criteria. The combination of isolated hyperferritinemia, normal iron loading, typical bilateral cataract, dominant pedigree, and a pathogenic FTL IRE variant is diagnostic.


11. Outcome and prognosis

Life expectancy is expected to be normal, and no HHCS-specific mortality signal, organ-failure risk, five- or ten-year survival estimate, or disease-specific death rate has been demonstrated. The principal morbidity is visual impairment. Hyperferritinemia is lifelong but does not itself signify progressive hepatic, cardiac, pancreatic, or neurologic iron injury. (millonig2010hyperferritinaemiacataractsyndromeworldwide pages 3-4, piperno2023hereditaryhyperferritinemia pages 10-12)

Visual prognosis after appropriately timed standard cataract treatment is generally favorable, although pediatric outcome depends on cataract density, age at intervention, amblyopia prevention, refractive rehabilitation, and postoperative complications. Quantitative HHCS-specific surgical response rates are unavailable. Some operated adults later required Nd:YAG capsulotomy, a common treatment for posterior capsule opacification rather than recurrence of the native lens cataract. (ferro2018ftlc.168g>cmutation pages 1-2)

Adverse prognosis is more likely to reflect delayed cataract treatment or iatrogenic iron depletion from inappropriate venesection than intrinsic systemic HHCS. No validated molecular prognostic biomarker beyond the causal genotype has been established.


12. Treatment

Established strategy

  1. Do not treat ferritin elevation alone. Neither phlebotomy nor chelation lowers the genetically dysregulated synthesis in a clinically useful way.
  2. Treat independent iron deficiency normally, guided by complete iron assessment.
  3. Monitor vision and lens morphology. Use refraction and amblyopia therapy in children where needed.
  4. Perform cataract extraction with optical rehabilitation when opacity materially impairs vision or threatens visual development.
  5. Continue routine postoperative surveillance, including posterior-capsule and glaucoma monitoring in pediatric cases. (moravikova2020hereditaryhyperferritinemiacataractsyndrome pages 1-7, eris2023hereditaryhyperferritinemiacataractsyndrome pages 4-5, piperno2023hereditaryhyperferritinemia pages 10-12, shiels2024throughthecatmap pages 3-4)

Suggested NCIT concepts include Cataract Surgery, Lens Extraction, Intraocular Lens Implantation, Phacoemulsification, Genetic Counseling, and Observation; identifiers should be mapped against the current NCIT release.

Avoidable harms

Misdiagnosed patients have undergone repeated venesection and developed iron-deficiency anemia. One patient received deferasirox and developed life-threatening acute hyperammonemia. These reports make avoidance of unindicated iron-removal therapy a central safety intervention. (moravikova2020hereditaryhyperferritinemiacataractsyndrome pages 1-7, eris2023hereditaryhyperferritinemiacataractsyndrome pages 4-5)

Experimental treatments and trials

No validated pharmacotherapy, ferritin-lowering drug, genotype-guided medication, gene therapy, CRISPR therapy, antisense oligonucleotide, siRNA, cell therapy, immunotherapy, or HHCS-specific interventional trial was identified. NCT05659017 (“Candidate Gene for Hyperferritinemia”) was retrieved as an observational study planned for 100 participants with status listed as unknown; it is not evidence of an HHCS treatment.

Gene editing and pharmacologic anti-cataract approaches are being studied for other cataract genes, but none can currently be extrapolated as HHCS therapy. (shiels2024throughthecatmapa pages 20-21, shiels2024throughthecatmap pages 19-21)


13. Prevention

Primary prevention

The occurrence of a de novo or inherited pathogenic allele cannot currently be prevented through lifestyle change or vaccination. Reproductive options following identification of a familial variant include prenatal diagnosis and preimplantation genetic testing after nondirective counseling, subject to local law and family preferences.

Secondary prevention

  • Cascade testing of first-degree relatives.
  • Baseline slit-lamp examination in mutation-positive children.
  • Early recognition of visually significant cataract during the developmental critical period.
  • Correct identification of isolated hyperferritinemia before invasive iron-overload investigations. (moravikova2020hereditaryhyperferritinemiacataractsyndrome pages 1-7, shiels2024throughthecatmap pages 3-4)

Tertiary prevention

  • Prevent amblyopia through timely surgery, refractive correction, and occlusion therapy when indicated.
  • Prevent iatrogenic anemia and chelator toxicity by avoiding phlebotomy/chelation without proven iron overload.
  • Educate patients to tell clinicians that their high ferritin is genetically driven and does not automatically indicate iron overload. (moravikova2020hereditaryhyperferritinemiacataractsyndrome pages 1-7, eris2023hereditaryhyperferritinemiacataractsyndrome pages 4-5)

No immunization, chemoprophylaxis, environmental intervention, or population newborn-screening program is indicated. Population carrier screening is not supported by current prevalence or outcome data.


14. Other species and natural disease

FTL and the IRE–IRP regulatory system are evolutionarily conserved across mammals, but no naturally occurring companion-animal, livestock, or wildlife syndrome convincingly equivalent to human HHCS was identified. Consequently, no breed-specific VBO annotation, veterinary prevalence, transmission pattern, cross-species susceptibility, or zoonotic potential can be assigned. HHCS is genetic and noncommunicable.

For comparative annotation, Mus musculus (NCBI Taxonomy 10090), Danio rerio (7955), and other vertebrates possess ferritin/iron-regulatory orthologs useful for studying general iron biology, but that does not constitute natural HHCS.


15. Model organisms and experimental systems

Available evidence

The strongest disease-specific experimental model is in vitro RNA–protein analysis. Mutant and wild-type FTL IRE RNAs have been assessed by structure prediction and direct/competitive EMSA with recombinant IRP1. The c.-151A>G mutant retained binding but had markedly impaired affinity, providing functional support for pathogenicity. (sompele2017functionalcharacterizationofa pages 8-9, sompele2017functionalcharacterizationof pages 8-9, sompele2017functionalcharacterizationofa pages 2-3)

Human extracted-lens material showing crystalline, immunoreactive L-ferritin deposits provides ex vivo pathological validation. (lachlan2004clinicalfeaturesand pages 3-4)

Model gaps

No well-validated mouse, rat, rabbit, zebrafish, Drosophila, organoid, or patient-iPSC model reproducing the complete HHCS triad—pathogenic FTL IRE allele, serum hyperferritinemia without iron overload, and characteristic ferritin cataract—was identified in the gathered evidence. FTL coding-mutant mice used for neuroferritinopathy and CRISPR models of other cataract genes should not be mislabeled as HHCS models. (shiels2024throughthecatmapa pages 20-21, shiels2024throughthecatmapa pages 29-30, shiels2024throughthecatmap pages 19-21)

A useful future model would be an FTL-IRE knock-in animal or human lens organoid carrying a recurrent pathogenic allele, with quantitative IRP occupancy, ribosome profiling, ferritin composition, lens transparency, aggregate imaging, and rescue by allele-selective translational repression.


Recent developments and expert interpretation

  • 2023: Piperno, Pelucchi, and Mariani consolidated HHCS within hereditary hyperferritinemias with normal transferrin saturation and emphasized stepwise biochemical/genetic diagnosis and avoidance of iron-removal treatment. Published January 2023; DOI 10.3390/ijms24032560. (piperno2023hereditaryhyperferritinemia pages 10-12)
  • 2023 human safety lesson: an HHCS family with coexisting HFE H63D illustrated that incidental HFE findings can anchor clinicians incorrectly on hemochromatosis; the patient had received ineffective phlebotomy and chelation. Published March 2023; DOI 10.7759/cureus.36253. (eris2023hereditaryhyperferritinemiacataractsyndrome pages 4-5)
  • 2024: contemporary cataract-genetics review supports broad panel/WES/WGS testing for heterogeneous inherited cataract, but HHCS remains best detected by ensuring explicit coverage of the noncoding FTL IRE. Published June 2024; DOI 10.3390/genes15060785. (shiels2024throughthecatmap pages 3-4, shiels2024throughthecatmap pages 19-21)

The expert consensus across these sources is that HHCS is usually medically benign outside the lens, highly recognizable when ferritin and cataract are considered together, and disproportionately harmful when mistaken for iron overload. The most effective “precision medicine” implementation today is therefore accurate molecular diagnosis, cascade assessment, avoidance of venesection/chelation, and individualized ophthalmic care. (moravikova2020hereditaryhyperferritinemiacataractsyndrome pages 1-7, eris2023hereditaryhyperferritinemiacataractsyndrome pages 4-5, piperno2023hereditaryhyperferritinemia pages 10-12)

Key references

  1. Piperno A, Pelucchi S, Mariani R. Hereditary Hyperferritinemia. Int J Mol Sci. Published January 2023. https://doi.org/10.3390/ijms24032560. (piperno2023hereditaryhyperferritinemia pages 10-12)
  2. Shiels A. Through the Cat-Map Gateway: A Brief History of Cataract Genetics. Genes. Published June 2024. https://doi.org/10.3390/genes15060785. (shiels2024throughthecatmap pages 3-4, shiels2024throughthecatmap pages 19-21)
  3. Moravikova J, et al. Hereditary hyperferritinemia-cataract syndrome in three Czech families. J AAPOS. Published December 2020. https://doi.org/10.1016/j.jaapos.2020.07.014. (moravikova2020hereditaryhyperferritinemiacataractsyndrome pages 1-7)
  4. Cadenas B, et al. L-Ferritin: One Gene, Five Diseases. Pharmaceuticals. Published January 2019. https://doi.org/10.3390/ph12010017. (cadenas2019lferritinonegene pages 1-3, cadenas2019lferritinonegene pages 5-8)
  5. Millonig G, Muckenthaler MU, Mueller S. Hyperferritinaemia-cataract syndrome: worldwide mutations and phenotype. Human Genomics. Published April 2010. https://doi.org/10.1186/1479-7364-4-4-250. (millonig2010hyperferritinaemiacataractsyndromeworldwide pages 3-4, millonig2010hyperferritinaemiacataractsyndromeworldwide pages 9-10)
  6. Lachlan KL, Temple IK, Mumford AD. Clinical features and molecular analysis of seven British kindreds. Eur J Hum Genet. Published online July 28, 2004; issue October 2004. https://doi.org/10.1038/sj.ejhg.5201252. (lachlan2004clinicalfeaturesand pages 3-4, lachlan2004clinicalfeaturesand pages 1-2)
  7. Ferro E, et al. FTL c.-168G>C Mutation in HHCS. Pediatr Dev Pathol. Published February 2018. https://doi.org/10.1177/1093526618755200. (ferro2018ftlc.168g>cmutation pages 1-2)
  8. Cosentino I, et al. Long-term ophthalmic observations in an Italian family. Ophthalmic Genet. Published February 5, 2016. https://doi.org/10.3109/13816810.2015.1059460. (cosentino2016hyperferritinemiacataractsyndromelongterm pages 1-6)

References

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  15. (shiels2024throughthecatmap pages 3-4): Alan Shiels. Through the cat-map gateway: a brief history of cataract genetics. Jun 2024. URL: https://doi.org/10.3390/genes15060785, doi:10.3390/genes15060785. This article has 22 citations.

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Off topic 0

Unresolved references

These identifiers did not resolve to a record and may be fabricated. A lookup that failed for transport reasons is indistinguishable from one that failed because the record does not exist, so spot-check before acting on them:

  • DOI:10.1007/s00439-017-1835-3 (3 mentions) - Identifier did not resolve to a record

Term Validation

Checked with linkml-term-validator 0.4.5, through the ols: adapter.

Outcome Count
Terms checked 4
Resolved 4
Unresolved (possible confabulation) 0
Obsolete 0
Unverifiable 0
Terms whose name was checked 3
Terms named correctly 2
Terms named as a different term 1

Terms the report names something else

These identifiers resolve, so nothing about them looks wrong, and the ontology calls them something unrelated to what the report calls them. That usually means the identifier is not the one the sentence needs:

  • MONDO:0010952 (2 mentions) - the report calls it "if available"; MONDO calls it hereditary hyperferritinemia with congenital cataracts