Nance-Horan Syndrome

Mendelian MONDO:0010545 Pathograph 41 Show in embeddings browser X-linked genetic disorders Syndromic congenital cataract Disorders of tooth development

Nance-Horan syndrome is a rare X-linked developmental disorder caused by loss of function of NHS, a gene at Xp22.13 encoding a regulator of actin remodelling and of epithelial cell junctions. Hemizygous males have dense bilateral congenital cataracts with microcornea, distinctive dental anomalies (screwdriver-shaped incisors, bud-shaped molars and supernumerary teeth), a long face with a prominent or bulbous nose and anteverted ears, and in about a third of cases intellectual disability. Heterozygous females usually show a milder phenotype, most characteristically lens opacities centred on the posterior Y-suture, with expressivity that varies with the pattern of X-chromosome inactivation. Copy number changes that alter NHS transcription without abolishing the protein cause isolated X-linked congenital cataract (cataract 40), which is an allelic but separately classified disease.

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1
Inheritance
10
Pathophys.
24
Phenotypes
41
Pathograph
1
Genes
3
Variants
3
Medical Actions
1
Models
1
Deep Research
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Inheritance

1
X-linked inheritance HP:0001417
NHS lies on Xp22.13. Hemizygous males carry the full phenotype, while heterozygous females range from unaffected to a near-complete male-like presentation, most often showing posterior Y-sutural lens opacities with or without mild dental and facial features. Because heterozygotes commonly express the trait, the condition is described as X-linked dominant in some reports and X-linked recessive in others; the generic X-linked term is bound here for that reason, matching ClinGen's XL designation. Female expressivity tracks X-inactivation, which is recorded as a pathophysiology node rather than as somatic mosaicism.
X-linked inheritance Expressivity: VARIABLE
Show evidence (3 references)
PMID:14564667 SUPPORT Human Clinical
"Nance-Horan syndrome (NHS) is an X-linked disorder characterized by congenital cataracts, dental anomalies, dysmorphic features, and, in some cases, mental retardation."
Gene-discovery study describing the X-linked inheritance of the syndrome.
PMID:6467651 SUPPORT Human Clinical
"Previous reports have described blindness in affected males but posterior sutural cataracts with normal vision as the primary ocular expression in heterozygous females."
Family study documenting full expression in hemizygous males and milder expression in heterozygous females.
CGGV:assertion_a7f57ca3-efb2-4333-9ae1-732aa429f37a-2017-10-20T100000.000Z SUPPORT Other
"NHS | HGNC:7820 | Nance-Horan syndrome | MONDO:0010545 | XL | Definitive"
ClinGen records the mode of inheritance for the NHS gene-disease pair as X-linked.
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Pathophysiology

10
NHS Loss of Function
Truncating variants, deletions and gene-disrupting rearrangements leave no functional NHS protein. NHS is expressed in a temporally and spatially regulated pattern in the developing eye, teeth, brain and craniofacial region, which is where its loss produces the syndrome. NHS has no enzymatic activity and no GO molecular function annotation; its known activity is binding, through its WAVE homology domain, the WAVE regulatory complex subunits that it assembles into a WAVE shell complex (evidence on the downstream node Loss of NHS WAVE Shell Complex), which is the function bound here as decreased.
NHS hgnc:7820 HUGO Gene Nomenclature Committee (hgnc) Relation: this pathophysiological event involves this gene This pathophysiological event involves NHS (hgnc:7820). hgnc:7820 is a gene from the HUGO Gene Nomenclature Committee.
WAVE regulatory complex subunit binding GO:0044877 ↓ DECREASED Gene Ontology (GO) Relation: this pathophysiological event involves this molecular function This pathophysiological event involves decreased WAVE regulatory complex subunit binding, annotated with protein-containing complex binding (GO:0044877). GO:0044877 is a molecular function from the Gene Ontology.
Animal models
Xcat mouse Mouse partially recapitulates Isoform-selective loss of the exon 1 Nhs isoform causing congenital cataract.
Downstream
Loss of NHS-A at Epithelial Tight Junctions Truncated NHS-A protein fails to reach the cell periphery where the wild-type isoform associates with ZO-1.
Loss of NHS WAVE Shell Complex Without NHS, its N-terminal WAVE homology domain no longer assembles the WAVE shell complex, and C-terminal truncations reduce NHS function in the same assay.
Mosaic NHS Expression in Heterozygous Females In heterozygous females, X-inactivation leaves a mixture of cells expressing the normal or the mutant allele, and skewing sets how much functional NHS remains.
Abnormal Ocular Development
Abnormal Odontogenesis
Craniofacial Dysmorphogenesis
Abnormal Brain Development
Short metacarpal Brachymetacarpalia is part of the classical description; no skeletal mechanism for NHS has been studied.
Show evidence (2 references)
CGGV:assertion_a7f57ca3-efb2-4333-9ae1-732aa429f37a-2017-10-20T100000.000Z SUPPORT Other
"The mechanism of pathogenicity is loss of function."
ClinGen curation states loss of function as the disease mechanism.
PMID:41236159 SUPPORT Human Clinical
"It is caused by deleterious loss of function variants or deletions involving the NHS gene at Xp22.13."
Recent cohort study summarising the allelic basis as loss of function.
Loss of NHS-A at Epithelial Tight Junctions
The NHS-A isoform associates with the apical membrane of epithelial cells, co-localises and co-immunoprecipitates with the tight junction protein ZO-1, and in the developing lens is restricted to the lens epithelium. Loss or mislocalisation of NHS-A removes it from these junctions.
lens epithelial cell CL:0002224 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves lens epithelial cell (CL:0002224). CL:0002224 is a cell type from the Cell Ontology.
tight junction GO:0070160 Gene Ontology (GO) Relation: this pathophysiological event involves this cellular component This pathophysiological event involves tight junction (GO:0070160). GO:0070160 is a cellular component from the Gene Ontology.
Downstream
Lens Epithelial Intercellular Contact Disruption Proposed, not demonstrated in lens tissue: loss of junctional NHS-A is expected to weaken cell-cell contacts in the lens epithelium.
Show evidence (3 references)
PMID:16675532 SUPPORT In Vitro
"We show that the endogenous and exogenous NHS-A isoform localizes to the cell membrane of mammalian cells in a cell-type-dependent manner and that it co-localizes with the tight junction (TJ) protein ZO-1 in the apical aspect of cell membrane in epithelial cells."
Establishes the junctional localisation of NHS-A that is lost in disease.
PMID:19447104 SUPPORT In Vitro
"it immunoprecipitates with the tight junction protein ZO-1 in MDCK (Madin Darby Canine Kidney) epithelial cells and in neonatal rat lens"
NHS-A physically associates with ZO-1 in epithelial cells and lens.
PMID:16675532 SUPPORT Model Organism
"In the developing mammalian lens, we found continuous expression of NHS that became restricted to the lens epithelium in pre- and postnatal lens."
Places NHS in the lens epithelium, the cell population relevant to cataract.
Loss of NHS WAVE Shell Complex
The N-terminus of the long NHS isoforms is a functional WAVE homology domain that binds ABI, HSPC300 (BRK1), NCKAP1 (Nap1) and CYFIP (Sra1), the WAVE regulatory complex subunits other than WAVE itself, forming a WAVE shell complex. Without NHS, ABI1 no longer associates with the WIPF2/N-WASP complex.
SCAR complex GO:0031209 Gene Ontology (GO) Relation: this pathophysiological event involves this cellular component This pathophysiological event involves SCAR complex (GO:0031209). GO:0031209 is a cellular component from the Gene Ontology.
Downstream
Disorganised Actin Cytoskeleton and Lamellipodial Dynamics The NHS WAVE shell complex remodels nucleation-promoting factor complexes that feed Arp2/3-dependent branched actin assembly.
Show evidence (2 references)
PMID:20332100 SUPPORT In Vitro
"The N-terminus of isoforms NHS-A and NHS-1A, implicated in the pathogenesis of NHS, have a functional WAVE homology domain that interacts with the Abi protein family, haematopoietic stem/progenitor cell protein 300 (HSPC300), Nap1 and Sra1."
Defines the WAVE homology domain and its WAVE regulatory complex partners.
PMID:42595116 SUPPORT In Vitro
"we identified as major NHS partners all subunits of the WAVE Regulatory Complex (WRC) except WAVE subunits themselves, indicating that the WHD of NHS assembles a WAVE Shell Complex (WSC)."
Proteomics of NHS isoform 1 identifies the WAVE shell complex.
Disorganised Actin Cytoskeleton and Lamellipodial Dynamics
NHS knockdown disrupts the actin cytoskeleton and the circumferential actin ring, increases cell spreading and lamellipod formation, and NHS knockout reduces the persistence of cell migration. These are cultured-cell phenotypes; the corresponding defect in developing lens, tooth or brain tissue has not been shown.
actin cytoskeleton organization GO:0030036 ⚠ ABNORMAL Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves abnormal actin cytoskeleton organization (GO:0030036). GO:0030036 is a biological process from the Gene Ontology. regulation of lamellipodium assembly GO:0010591 ⚠ ABNORMAL Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves abnormal regulation of lamellipodium assembly (GO:0010591). GO:0010591 is a biological process from the Gene Ontology. cell migration GO:0016477 ↓ DECREASED Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves decreased cell migration (GO:0016477). GO:0016477 is a biological process from the Gene Ontology.
Downstream
Abnormal Ocular Development Proposed link from defective actin remodelling to developmental morphogenesis; not demonstrated in vivo.
Show evidence (3 references)
PMID:20332100 SUPPORT In Vitro
"NHS knockdown resulted in the disruption of the actin cytoskeleton."
Direct cellular consequence of NHS depletion.
PMID:20332100 SUPPORT In Vitro
"We show that NHS controls cell morphology by maintaining the integrity of the circumferential actin ring and controlling lamellipod formation."
NHS is required to maintain cortical actin organisation and restrain lamellipodia.
PMID:42595116 SUPPORT In Vitro
"NHS KO cells displayed reduced migration persistence, a phenotype that was fully rescued by the long isoform 1 (i1) that contains an N-terminal WAVE Homology Domain (WHD), but only partially rescued by the short isoform two (i2), which does not."
Knockout reduces migration persistence, rescued by the WHD-containing isoform.
Lens Epithelial Intercellular Contact Disruption
Weakened intercellular contacts in the lens epithelium are the proposed tissue-level basis of the dense congenital cataract. The mouse Xcat model shows that the defect acts within lens cells.
epithelium of lens UBERON:0001803 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in epithelium of lens (UBERON:0001803). UBERON:0001803 is an anatomical location from the Uberon multi-species anatomy ontology.
Downstream
Congenital cataract
Show evidence (2 references)
PMID:16675532 SUPPORT INDIRECT In Vitro
"This study suggests that disturbances in intercellular contacts underlie cataractogenesis in the Nance-Horan syndrome."
The authors' inference from NHS-A junctional localisation; not directly measured in patient lens.
PMID:2272505 SUPPORT Model Organism
"the site of gene action for the Xcat locus is suggested to be endogenous to the lens cells"
Variegated lens opacity in heterozygous Xcat mice places the gene's action inside lens cells.
Abnormal Ocular Development
Beyond the lens, NHS loss is associated with a small cornea and eye and with maldevelopment of the anterior chamber angle, which predisposes to childhood glaucoma, and retinal cystoid degeneration has been described on histopathology.
camera-type eye development GO:0043010 ⚠ ABNORMAL Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves abnormal camera-type eye development (GO:0043010). GO:0043010 is a biological process from the Gene Ontology.
Downstream
Microcornea
Microphthalmia
Childhood glaucoma Abnormal anterior chamber angle development underlies the infantile glaucoma.
Retinal degeneration
Show evidence (1 reference)
PMID:19941417 SUPPORT Human Clinical
"We report a new pathological finding of severe retinal cystoid degeneration in this NHS patient and confirm abnormal development of the anterior chamber angle structure."
Ocular histopathology showing developmental anomaly of the anterior chamber angle and retinal degeneration.
Abnormal Odontogenesis
NHS loss alters tooth number and crown shape in both dentitions, producing screwdriver-shaped incisors, bud-shaped molars, supernumerary teeth (including mesiodens) and, less often, tooth agenesis.
odontogenesis GO:0042476 ⚠ ABNORMAL Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves abnormal odontogenesis (GO:0042476). GO:0042476 is a biological process from the Gene Ontology.
Downstream
Screwdriver-shaped incisors
Bud-shaped molars
Supernumerary teeth
Mesiodens
Diastema
Tooth agenesis
Show evidence (1 reference)
PMID:27616609 SUPPORT Human Clinical
"The only consistent and very clear dental aberration was alterations in the tooth morphology that is screwdriver-shaped incisors and bud molars being most pronounced in the permanent dentition, but were also present in the primary dentition."
Dental case series and literature review defining the characteristic dental developmental anomaly.
Craniofacial Dysmorphogenesis
Affected males and many carrier females share a recognisable facial gestalt with a long narrow face, a prominent or bulbous nose, mandibular prognathism and large anteverted ears.
Downstream
Long face
Bulbous nose
Prominent nose
Anteverted ears
Mandibular prognathia
Show evidence (1 reference)
PMID:22229851 SUPPORT Human Clinical
"All seven affected family members had congenital or infantile cataract and facial dysmorphism (long face, bulbous nose, abnormal dentition)."
Facial dysmorphism in all affected members of a genotyped family.
Abnormal Brain Development
About a third of affected males have intellectual disability, usually mild to moderate, sometimes with autistic traits; regression with corpus callosum anomalies and leukoencephalopathy has been reported in a single boy. How NHS loss affects brain development is not known.
Downstream
Intellectual disability
Autistic behavior
Show evidence (2 references)
PMID:9268101 SUPPORT Human Clinical
"Our study confirms that mental retardation (MR) can be a major component of the NHS."
Clinical and neuropsychological assessment establishing the neurodevelopmental component.
PMID:34573171 SUPPORT Human Clinical
"The affected boy from this family presented a late regression of cognitive, motor, language, and adaptive skills, as well as broad behavioral anomalies."
Single-family report of neurodevelopmental regression, with corpus callosum anomalies and leukoencephalopathy on imaging.
Mosaic NHS Expression in Heterozygous Females
In a heterozygous female each cell expresses either the normal or the mutant NHS allele according to which X is active. Random inactivation usually yields a mild phenotype, classically posterior Y-sutural lens opacities; skewed inactivation of the normal X, or of the normal X in a balanced X-autosome translocation carrier, produces a male-like presentation. This is X-inactivation mosaicism of a germline allele, not post-zygotic somatic mosaicism.
NHS hgnc:7820 HUGO Gene Nomenclature Committee (hgnc) Relation: this pathophysiological event involves this gene This pathophysiological event involves NHS (hgnc:7820). hgnc:7820 is a gene from the HUGO Gene Nomenclature Committee.
Animal models
Xcat mouse Mouse recapitulates Heterozygous females show variegated lens opacity, the mouse counterpart of variable carrier expression.
Downstream
Posterior Y-sutural cataract
Show evidence (2 references)
PMID:36370055 SUPPORT Human Clinical
"The variability among female carriers presumably results from nonrandom X chromosome inactivation."
Skewed X-inactivation with reduced NHS expression in an affected female carrier of an NHS microdeletion.
PMID:2272505 SUPPORT Model Organism
"A variegated pattern of lens opacity was evident in female heterozygotes."
Variegated lens opacity in heterozygous Xcat mice reflects X-inactivation mosaicism within the lens.
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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 Nance-Horan Syndrome 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

24
Cardiovascular 1
Congenital heart defect Abnormal heart morphology HP:0001627 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Congenital heart defect, annotated with Abnormal heart morphology (HP:0001627). HP:0001627 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:34573171 SUPPORT Human Clinical
"NHS is characterized by congenital cataracts, dental anomalies, and distinctive facial features, and a proportion of the affected individuals also present intellectual disability and congenital cardiopathies."
Congenital cardiopathies are reported in a proportion of patients.
PMID:37221585 SUPPORT Human Clinical
"index (P2) presenting with global developmental delay, microphthalmia, cataracts, and ventricular septal defect"
A ventricular septal defect in a patient with a deletion including NHS and 21 other genes, so attribution to NHS alone is uncertain.
Ear 1
Anteverted ears HP:0040080 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Anteverted pinnae, annotated with Anteverted ears (HP:0040080). HP:0040080 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:1969135 SUPPORT Human Clinical
"The Nance-Horan syndrome (NHS) is an infrequent X-linked disorder typified by dense congenital central cataracts, microcornea, anteverted and simplex pinnae, brachymetacarpalia, and numerous dental anomalies."
Anteverted pinnae are part of the classical definition.
PMID:30642278 SUPPORT Human Clinical
"who presented with a long-narrow face, prominent nose and large anteverted pinnae ear"
Large anteverted pinnae in a molecularly confirmed proband.
Eye 9
Congenital cataract Developmental cataract HP:0000519 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Congenital cataract, annotated with Developmental cataract (HP:0000519). HP:0000519 is a phenotype from the Human Phenotype Ontology.
Sequelae: Visual impairment Nystagmus Strabismus
Show evidence (3 references)
PMID:1969135 SUPPORT Human Clinical
"The Nance-Horan syndrome (NHS) is an infrequent X-linked disorder typified by dense congenital central cataracts, microcornea, anteverted and simplex pinnae, brachymetacarpalia, and numerous dental anomalies."
Classical clinical definition from five multigenerational kindreds.
PMID:22229851 SUPPORT Human Clinical
"All seven affected family members had congenital or infantile cataract and facial dysmorphism (long face, bulbous nose, abnormal dentition)."
Congenital or infantile cataract in every affected member of a genotyped family.
PMID:17451191 SUPPORT Human Clinical
"Ultrasound demonstrated fetal bilateral congenital cataract."
Bilateral cataract is already present before birth in an NHS-mutation fetus.
Posterior Y-sutural cataract HP:0008031 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Posterior Y-sutural cataract (HP:0008031). HP:0008031 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:22229851 SUPPORT Human Clinical
"Four had posterior Y-suture centered lens opacities; these four also exhibited the facial dysmorphism of the seven affected family members."
Posterior Y-sutural opacities in heterozygous females carrying the familial NHS mutation.
PMID:29402928 SUPPORT Human Clinical
"One female carrier displayed lens opacities centered on the posterior Y-suture in both eyes, as well as mild dental abnormalities."
Independent family with the same carrier lens finding.
Microcornea HP:0000482 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Microcornea (HP:0000482). HP:0000482 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:9268101 SUPPORT Human Clinical
"Nance-Horan syndrome (NHS) is a rare X-linked condition comprising congenital cataract with microcornea, distinctive dental, and evocative facial anomalies."
Microcornea is part of the core ocular definition.
PMID:23566852 SUPPORT Human Clinical
"We describe two brothers who have the NHS phenotype and their carrier mother who had microcornea but not cataract."
Microcornea without cataract in a heterozygous carrier.
Microphthalmia HP:0000568 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Microphthalmia (HP:0000568). HP:0000568 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:23566852 SUPPORT Human Clinical
"Microcornea, microphthalmia and mild or moderate mental retardation may accompany these features."
Microphthalmia is an accompanying ocular feature.
Nystagmus HP:0000639 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Nystagmus (HP:0000639). HP:0000639 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:35122698 SUPPORT Human Clinical
"The clinical phenotype in males includes congenital cataracts, vision loss, microcornea, nystagmus, microphthalmia, glaucoma, screwdriver blade-shaped incisors, supernumerary maxillary incisors, diastema, delays, intellectual disability, and dysmorphic facies."
Nystagmus is listed in the male phenotype.
Strabismus HP:0000486 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Strabismus (HP:0000486). HP:0000486 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:29042737 SUPPORT Human Clinical
"ocular abnormalities such as congenital cataract, microcornea, microphthalmia and strabismus"
Strabismus is among the ocular abnormalities of the syndrome.
Childhood glaucoma Developmental glaucoma HP:0001087 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Infantile glaucoma, annotated with Developmental glaucoma (HP:0001087). HP:0001087 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:19941417 SUPPORT Human Clinical
"Classic and novel ocular pathological findings of a young male with NHS are described, including congenital cataracts, infantile glaucoma, scleral staphyloma, and severe retinal cystoid degeneration."
Infantile glaucoma in a patient with NHS.
PMID:35122698 SUPPORT Human Clinical
"The clinical phenotype in males includes congenital cataracts, vision loss, microcornea, nystagmus, microphthalmia, glaucoma, screwdriver blade-shaped incisors, supernumerary maxillary incisors, diastema, delays, intellectual disability, and dysmorphic facies."
Glaucoma is part of the reported male phenotype.
Retinal degeneration HP:0000546 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Retinal cystoid degeneration, annotated with Retinal degeneration (HP:0000546). HP:0000546 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:19941417 SUPPORT Human Clinical
"We report a new pathological finding of severe retinal cystoid degeneration in this NHS patient"
Histopathological retinal cystoid degeneration in an NHS eye.
Visual impairment HP:0000505 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Profound visual impairment, annotated with Visual impairment (HP:0000505). HP:0000505 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:41236159 SUPPORT Human Clinical
"bilateral congenital cataracts leading to profound vision loss"
Profound vision loss is the main functional consequence of the cataract.
Head and Neck 10
Screwdriver-shaped incisors HP:0006346 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Screwdriver-shaped incisors (HP:0006346). HP:0006346 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:27616609 SUPPORT Human Clinical
"The combination of congenital cataract, screwdriwer-shaped incisors and bud-shaped molars is a strong clinical indication of Nance-Horan syndrome."
Screwdriver-shaped incisors are a diagnostic dental hallmark (the source misspells screwdriver).
Bud-shaped molars Abnormal molar morphology HP:0011070 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Bud-shaped molars, annotated with Abnormal molar morphology (HP:0011070). HP:0011070 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:27616609 SUPPORT Human Clinical
"In the description of molar morphology in NHS patients, it is recommended to use the term "bud molar.""
Defines the molar anomaly and its preferred terminology.
Supernumerary teeth Supernumerary tooth HP:0011069 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Supernumerary teeth, annotated with Supernumerary tooth (HP:0011069). HP:0011069 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:27616609 SUPPORT Human Clinical
"In addition, three patients had supernumerary teeth, and three had dental agenesis."
Supernumerary teeth in three of seven patients in a dental case series.
PMID:37221585 SUPPORT Human Clinical
"dental findings including Hutchinson incisors, supernumerary teeth, bud-shaped molars"
Supernumerary teeth with the other characteristic dental findings in a genotyped proband.
Mesiodens HP:0011067 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Mesiodens (HP:0011067). HP:0011067 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:6467651 SUPPORT Human Clinical
"In one of these two families, the affected female is not only blind in one eye but reportedly had supernumerary central incisors (mesiodens) removed."
Mesiodens in a severely affected heterozygous female.
Diastema HP:0000699 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Diastema (HP:0000699). HP:0000699 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:35122698 SUPPORT Human Clinical
"The clinical phenotype in males includes congenital cataracts, vision loss, microcornea, nystagmus, microphthalmia, glaucoma, screwdriver blade-shaped incisors, supernumerary maxillary incisors, diastema, delays, intellectual disability, and dysmorphic facies."
Diastema is part of the reported male dental phenotype.
Tooth agenesis HP:0009804 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Tooth agenesis (HP:0009804). HP:0009804 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:27616609 SUPPORT Human Clinical
"In addition, three patients had supernumerary teeth, and three had dental agenesis."
Dental agenesis in three of seven patients.
Long face HP:0000276 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Long face (HP:0000276). HP:0000276 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:22229851 SUPPORT Human Clinical
"All seven affected family members had congenital or infantile cataract and facial dysmorphism (long face, bulbous nose, abnormal dentition)."
Long face in all affected members of a genotyped family.
Bulbous nose HP:0000414 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Bulbous nose (HP:0000414). HP:0000414 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:22229851 SUPPORT Human Clinical
"All seven affected family members had congenital or infantile cataract and facial dysmorphism (long face, bulbous nose, abnormal dentition)."
Bulbous nose in all affected members of a genotyped family.
Prominent nose HP:0000448 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Prominent nose (HP:0000448). HP:0000448 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:29042737 SUPPORT Human Clinical
"It is characterized by facial dysmorphism such as long face, prominent nose and mandibular prognathism"
Prominent nose is part of the facial dysmorphism.
PMID:30642278 SUPPORT Human Clinical
"who presented with a long-narrow face, prominent nose and large anteverted pinnae ear"
Prominent nose in a molecularly confirmed proband.
Mandibular prognathia HP:0000303 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Mandibular prognathism, annotated with Mandibular prognathia (HP:0000303). HP:0000303 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:29042737 SUPPORT Human Clinical
"It is characterized by facial dysmorphism such as long face, prominent nose and mandibular prognathism"
Mandibular prognathism is part of the facial dysmorphism.
Limbs 1
Short metacarpal HP:0010049 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Brachymetacarpalia, annotated with Short metacarpal (HP:0010049). HP:0010049 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:1969135 SUPPORT Human Clinical
"The Nance-Horan syndrome (NHS) is an infrequent X-linked disorder typified by dense congenital central cataracts, microcornea, anteverted and simplex pinnae, brachymetacarpalia, and numerous dental anomalies."
Brachymetacarpalia is part of the classical definition.
Nervous System 2
Intellectual disability FREQUENT HP:0001249 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Intellectual disability (HP:0001249). HP:0001249 is a phenotype from the Human Phenotype Ontology.
Show evidence (3 references)
PMID:9268101 SUPPORT Human Clinical
"Combining our data with those from the literature leads to a frequency of MR in NHS of around 30%. In most cases, MR is mild or moderate (80%) and not associated with motor delay."
Pooled frequency of about 30% supports the FREQUENT band (30-79%) at its lower edge, and the severity distribution.
PMID:9268101 SUPPORT Human Clinical
"MR has intra- and inter-familial variability but does not appear to be expressed in carriers."
Variability between and within families, and absence in carrier females.
PMID:25091991 SUPPORT BACKGROUND Human Clinical
"Mental retardation was present in about 30% of the reported cases."
Independent restatement of the roughly 30% frequency in the literature.
Autistic behavior HP:0000729 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Autistic traits, annotated with Autistic behavior (HP:0000729). HP:0000729 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:9268101 SUPPORT Human Clinical
"Conversely, a profound mental handicap associated with autistic traits may be observed."
Autistic traits accompany profound intellectual disability in some patients.
PMID:37221585 SUPPORT Human Clinical
"P3 also had autistic and psychobehavioral features."
Autistic features in a molecularly confirmed patient.
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Genetic Associations

1
NHS (Loss-of-function)
Gene: NHS hgnc:7820 HUGO Gene Nomenclature Committee (hgnc) Relation: this disease-associated gene is this gene This disease-associated gene is NHS (hgnc:7820). hgnc:7820 is a gene from the HUGO Gene Nomenclature Committee. relationship_type: CAUSATIVE
Show evidence (5 references)
PMID:14564667 SUPPORT PRIMARY RESULT Human Clinical
"have identified protein-truncating mutations in a novel gene, which we have called "NHS," in five families."
Original identification of truncating NHS mutations in five Nance-Horan syndrome families.
PMID:15466011 SUPPORT PRIMARY RESULT Human Clinical
"A novel gene NHS, with no known function, was identified as causative for NHS. Protein truncating mutations were detected in all three NHS pedigrees"
Independent identification of NHS as the causal gene.
PMID:19414485 SUPPORT PRIMARY RESULT Human Clinical
"identifying four novel protein truncation mutations and a novel large deletion encompassing the majority of the NHS gene, all leading to no functional protein"
Truncating mutations and a large deletion in seven syndromic families, all predicted to abolish the protein.
+ 2 more references
Variants (3)
NHS c.115C>T p.(Gln39Ter) Pathogenic
single nucleotide variant
Exon 1 nonsense variant segregating in a four-generation Asian Indian family with eight affected males, who had severe ocular but mild to moderate non-ocular features.
Show evidence (1 reference)
PMID:15623749 SUPPORT Human Clinical
"revealed a truncating mutation 115C-->T in exon 1, resulting in conversion of glutamine to stop codon (Q39X), but was not observed in unaffected individuals and control subjects"
Segregation of the Q39X nonsense allele with disease in affected males and carrier females.
NHS p.(Arg373Ter) Pathogenic
single nucleotide variant
Recurrent nonsense variant reported in unrelated families from different countries.
Show evidence (2 references)
PMID:18949062 SUPPORT Human Clinical
"each of the two other patients carried two previously reported mutations (R373X and R879X)"
R373X recurs as a previously reported truncating allele in a new patient series.
PMID:31755796 SUPPORT Human Clinical
"Two pathogenic variants were found in the NHS gene: a nonsense mutation (p.Arg373X) and a frameshift mutation (p.His669ProfsX5)."
The same nonsense allele in an unrelated Spanish family.
Xp22.13 microdeletions including NHS Pathogenic
copy number variation
Contiguous deletions removing NHS together with neighbouring genes such as REPS2, SCML1 and RAI2 cause the classical syndrome, and larger deletions can add features attributable to the co-deleted genes.
Show evidence (3 references)
PMID:35122698 SUPPORT Human Clinical
"With the evolution of array-CGH technology, a total of five kindreds with NHS have been reported in the medical literature with microdeletions encompassing the NHS gene rather than sequencing variants."
Summarises microdeletions as a recurrent class of Nance-Horan syndrome alleles.
PMID:36370055 SUPPORT Human Clinical
"The microdeletion contains the REPS2 and NHS genes and was inherited from a phenotypically normal mother."
A heterozygous Xp22.13 microdeletion removing NHS in an affected female.
PMID:20882036 SUPPORT Human Clinical
"The deleted region encompasses the REPS2, NHS, SCML1 and RAI2 genes, and was transmitted from their carrier mother who presented only mild cataract."
A familial Xp22.13 microdeletion including NHS in two affected brothers, with mild expression in the carrier mother.
💊

Medical Actions

3
Congenital cataract surgery
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. Ontology label: Cataract Surgery NCIT:C157809
Platform: Surgery
Surgical removal of the dense congenital cataracts in infancy, followed by optical correction and amblyopia therapy, following the general management of infantile cataract. No Nance-Horan-specific surgical outcome study was found. Glaucoma after infant cataract surgery is common in general, so the glaucoma seen in this syndrome needs follow-up whether developmental or postoperative.
Target Phenotypes: Congenital cataract HP:0000519 Human Phenotype Ontology (HP) Relation: this treatment targets this phenotype This treatment targets Congenital cataract, annotated with Developmental cataract (HP:0000519). HP:0000519 is a phenotype from the Human Phenotype Ontology.
Show evidence (3 references)
PMID:31317088 SUPPORT INDIRECT REVIEW SYNTHESIS Human Clinical
"For significant lens opacity that leads to a considerable risk of amblyopia, cataract surgery is recommended at 6 weeks of age for unilateral cataract and between 6 and 8 weeks of age for bilateral cases."
General pediatric cataract guidance on surgical timing, applied to the bilateral congenital cataract of this syndrome; not a Nance-Horan-specific study.
PMID:35307324 SUPPORT INDIRECT REVIEW SYNTHESIS Human Clinical
"Better visual outcomes in operated eyes, however, are achieved in the setting of early presentation, bilateral infantile cataracts, absence of nystagmus or strabismus, and consistent amblyopia therapy."
General infantile cataract review on the determinants of visual outcome after surgery.
PMID:35307324 SUPPORT INDIRECT REVIEW SYNTHESIS Human Clinical
"The most common complications of cataract surgery performed in infancy are visual axis opacification and, in about a third of patients, the long-term development of glaucoma."
Supports postoperative glaucoma surveillance; a general infantile cataract figure, not measured in this syndrome.
Dental management
Action: dental procedureNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is dental procedure (NCIT:C38052). NCIT:C38052 is a clinical intervention from the NCI Thesaurus. Ontology label: Dental Procedure NCIT:C38052
Platform: Surgery
Dental care addresses supernumerary and malformed teeth, including extraction of supernumerary incisors.
Target Phenotypes: Supernumerary teeth HP:0011069 Human Phenotype Ontology (HP) Relation: this treatment targets this phenotype This treatment targets Supernumerary teeth, annotated with Supernumerary tooth (HP:0011069). HP:0011069 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:15660094 SUPPORT Human Clinical
"This case describes the management of a 9-year-old girl referred for the routine management of supernumerary teeth."
Case report of dental management of supernumerary teeth in Nance-Horan syndrome.
Educational support
Action: educational interventionNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is educational intervention (NCIT:C17874). NCIT:C17874 is a clinical intervention from the NCI Thesaurus. Ontology label: Educational Intervention NCIT:C17874
Platform: Behavioral / lifestyle
Awareness of intellectual disability guides educational planning for affected boys.
Target Phenotypes: Intellectual disability HP:0001249 Human Phenotype Ontology (HP) Relation: this treatment targets this phenotype This treatment targets Intellectual disability (HP:0001249). HP:0001249 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:9268101 SUPPORT Human Clinical
"Awareness of MR in NHS may be of importance in the management of the patients, especially in terms of education."
Recommends educational management for the intellectual disability component.
🔬

Diagnosis

4
Molecular genetic testing of NHS
Sequencing of NHS (as a gene panel or exome) confirms the diagnosis. It is recommended for familial bilateral pediatric cataract, because dental and neurodevelopmental features can take years to appear and families are otherwise counselled as having isolated cataract.
genetic testing NCIT:C15709 NCI Thesaurus (NCIT)
Show evidence (2 references)
PMID:39858638 SUPPORT Human Clinical
"This reinforces the importance of genetic testing of bilateral familial pediatric cataracts, especially since systemic features such as dental anomalies and intellectual disability may take years before they develop."
A family first diagnosed with isolated cataract was recognised as Nance-Horan syndrome only after sequencing.
PMID:40868138 SUPPORT Human Clinical
"NHS remains underdiagnosed due to its variable expressivity and the late manifestation of systemic features, often leading to misclassification as isolated CC."
Exome sequencing of a congenital cataract cohort identified NHS cases misclassified as isolated cataract.
Copy number and cytogenetic analysis
When NHS sequencing is negative, chromosomal microarray detects microdeletions including NHS, and karyotype or FISH detects balanced X-autosome translocations that disrupt NHS, particularly in affected females.
chromosomal microarray analysis NCIT:C18477 NCI Thesaurus (NCIT)
Show evidence (2 references)
PMID:35122698 SUPPORT Human Clinical
"A chromosomal microarray (CMA) was performed and revealed a 1.83-Mb interstitial microdeletion at Xp22.2p22.13"
Chromosomal microarray identified the causal NHS-containing deletion.
PMID:34620209 SUPPORT Human Clinical
"justifies consideration of karyotype and fluorescence in situ hybridization (FISH) analysis for female patients with familial NHS if single-gene analysis of NHS is negative"
Recommends cytogenetic analysis for sequence-negative affected females.
Dental examination
The combination of screwdriver-shaped incisors and bud molars is distinctive, so a dental examination can point to the diagnosis in a child with congenital cataract, and dentists may be the first to suspect it.
dental examination NCIT:C158323 NCI Thesaurus (NCIT)
Show evidence (1 reference)
PMID:27616609 SUPPORT Human Clinical
"a dental examination as a part of the diagnostic process may reveal distinct characteristics of the dental morphology, which could be of diagnostic value and facilitate an early diagnosis"
Recommends dental examination as part of diagnosis.
Ophthalmic examination of at-risk females
Slit-lamp examination of female relatives for posterior Y-sutural lens opacities identifies likely carriers; opacities of other morphology are not a carrier sign.
eye examination NCIT:C38060 NCI Thesaurus (NCIT)
Show evidence (1 reference)
PMID:22229851 SUPPORT Human Clinical
"Lens opacities that did not have this characteristic morphology in a suspected female carrier were not a carrier sign, even in the context of her affected family members."
Defines the specificity of the Y-sutural opacity for carrier detection.
🐁

Animal Models

1
Xcat mouse
The spontaneous X-linked cataract (Xcat) mouse carries an insertion between exons 1 and 2 of Nhs that abolishes the exon 1-containing isoform, leaving only the alternative exon 1A isoform, and reduces Nhs protein in lens fiber cells. Hemizygous males and homozygous females have fully penetrant cataract; heterozygous females show variegated lens opacity.
Species
Mouse
Genotype
Xcat, a large insertion between exons 1 and 2 of Nhs
Publication
PMID:16357105
Pathograph links
NHS Loss of Function partially recapitulates fidelity: moderate observes: organism Isoform-selective loss of the exon 1 Nhs isoform causing congenital cataract.
Limitations: The allele removes one isoform rather than the whole protein, and the cited abstracts report only the lens phenotype; dental, craniofacial and neurodevelopmental features are not described.
Show evidence (2 references)
PMID:16357105 SUPPORT Model Organism
"The insertion inhibits the expression of the Nhs1 isoform containing exon 1 and results in exclusive expression of the alternative isoform containing exon 1A."
Defines the isoform-selective loss of function in the model.
+ 1 more reference
Mosaic NHS Expression in Heterozygous Females recapitulates fidelity: moderate observes: tissue Heterozygous females show variegated lens opacity, the mouse counterpart of variable carrier expression.
Limitations: Mouse X-inactivation and lens growth differ from human, and Y-sutural localisation is not described.
Show evidence (1 reference)
PMID:2272505 SUPPORT Model Organism
"Phenotypic expression in Xcat heterozygous females ranges from totally clear to totally opaque lenses."
Variable heterozygous expression in the mouse model.
Show evidence (1 reference)
PMID:2272505 SUPPORT Model Organism
"In hemizygous males and homozygous females penetrance is complete with only slight variation in the degree of expression."
Fully penetrant cataract in hemizygous Xcat males.
{ }

Source YAML

click to show 
name: Nance-Horan Syndrome
creation_date: "2026-10-14T20:49:40Z"
category: Mendelian
synonyms:
- Nance-Horan syndrome
- NHS
- cataract-dental syndrome
- X-linked cataract-dental syndrome
- cataract-oto-dental syndrome
- mesiodens-cataract syndrome
- cataract X-linked with Hutchinsonian teeth
disease_term:
  preferred_term: Nance-Horan syndrome
  term:
    id: MONDO:0010545
    label: Nance-Horan syndrome
parents:
- X-linked genetic disorders
- Syndromic congenital cataract
- Disorders of tooth development
description: >-
  Nance-Horan syndrome is a rare X-linked developmental disorder caused by
  loss of function of NHS, a gene at Xp22.13 encoding a regulator of actin
  remodelling and of epithelial cell junctions. Hemizygous males have dense
  bilateral congenital cataracts with microcornea, distinctive dental anomalies
  (screwdriver-shaped incisors, bud-shaped molars and supernumerary teeth), a
  long face with a prominent or bulbous nose and anteverted ears, and in about
  a third of cases intellectual disability. Heterozygous females usually show a
  milder phenotype, most characteristically lens opacities centred on the
  posterior Y-suture, with expressivity that varies with the pattern of
  X-chromosome inactivation. Copy number changes that alter NHS transcription
  without abolishing the protein cause isolated X-linked congenital cataract
  (cataract 40), which is an allelic but separately classified disease.
notes: >-
  Scope and lump/split. Isolated X-linked congenital cataract (CXN; cataract
  40, MONDO:0010544, OMIM 302200) is allelic at NHS but is not lumped here,
  either as a subtype or as part of this entry. MONDO classifies it separately,
  under early-onset non-syndromic cataract, and the published mechanism
  differs: the two CXN families characterised in PMID:19414485 carried a
  complex duplication-triplication rearrangement and an intragenic deletion
  predicted to alter NHS transcriptional regulation, whereas the Nance-Horan
  syndrome alleles in the same study were truncations or deletions leaving no
  functional protein. A separate stub (stubs/Cataract_40.yaml) remains in the
  curation queue for it. The boundary is not absolute: truncating NHS variants
  are sometimes first diagnosed as isolated familial cataract because the
  dental and systemic features emerge later or are subtle (PMID:39858638,
  PMID:40868138), so a clinically isolated cataract with an NHS truncating
  allele belongs in this entry. A single missense allele (p.P551S) has been
  reported to segregate with the syndrome, including a cardiac anomaly, in one
  Tunisian family (PMID:21559051); it is not listed as a variant here because
  it is a single-family report against a loss-of-function mechanism otherwise
  carried by truncations and deletions. No GeneReviews chapter exists for this
  disease (PubMed query "Nance-Horan syndrome[TI] AND genereviews[book]"
  returned 0 records on 2026-10-14). No population prevalence figure was found
  in a quotable source; a 2017 case report states that the incidence has not
  been established (PMID:29042737). Hearing loss, axial hypotonia and foot
  contractures reported with a 1.83-Mb contiguous deletion (PMID:35122698) are
  not listed as phenotypes, because that deletion removes eight other genes.
inheritance:
- name: X-linked inheritance
  inheritance_term:
    preferred_term: X-linked inheritance
    term:
      id: HP:0001417
      label: X-linked inheritance
  expressivity: VARIABLE
  description: >-
    NHS lies on Xp22.13. Hemizygous males carry the full phenotype, while
    heterozygous females range from unaffected to a near-complete male-like
    presentation, most often showing posterior Y-sutural lens opacities with or
    without mild dental and facial features. Because heterozygotes commonly
    express the trait, the condition is described as X-linked dominant in some
    reports and X-linked recessive in others; the generic X-linked term is bound
    here for that reason, matching ClinGen's XL designation. Female expressivity
    tracks X-inactivation, which is recorded as a pathophysiology node rather
    than as somatic mosaicism.
  evidence:
  - reference: PMID:14564667
    reference_title: "Mutations in a novel gene, NHS, cause the pleiotropic effects of Nance-Horan syndrome, including severe congenital cataract, dental anomalies, and mental retardation."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Nance-Horan syndrome (NHS) is an X-linked disorder characterized by congenital cataracts, dental anomalies, dysmorphic features, and, in some cases, mental retardation."
    explanation: Gene-discovery study describing the X-linked inheritance of the syndrome.
  - reference: PMID:6467651
    reference_title: "The Nance-Horan syndrome: a rare X-linked ocular-dental trait with expression in heterozygous females."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Previous reports have described blindness in affected males but posterior sutural cataracts with normal vision as the primary ocular expression in heterozygous females."
    explanation: Family study documenting full expression in hemizygous males and milder expression in heterozygous females.
  - reference: CGGV:assertion_a7f57ca3-efb2-4333-9ae1-732aa429f37a-2017-10-20T100000.000Z
    reference_title: "NHS / Nance-Horan syndrome (Definitive)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "NHS | HGNC:7820 | Nance-Horan syndrome | MONDO:0010545 | XL | Definitive"
    explanation: ClinGen records the mode of inheritance for the NHS gene-disease pair as X-linked.
genetic:
- name: NHS
  gene_term:
    preferred_term: NHS
    term:
      id: hgnc:7820
      label: NHS
  relationship_type: CAUSATIVE
  association: Loss-of-function
  notes: >-
    Pathogenic alleles are mostly nonsense and frameshift variants, with
    partial or whole-gene deletions, an intragenic inversion and balanced
    X-autosome translocations that disrupt the gene. All are expected to leave
    no functional NHS protein.
  gene_disease_validity:
  - validity_classification: DEFINITIVE
    classified_by: CLINGEN
    external_id: CGGV:assertion_a7f57ca3-efb2-4333-9ae1-732aa429f37a-2017-10-20T100000.000Z
    evidence:
    - reference: CGGV:assertion_a7f57ca3-efb2-4333-9ae1-732aa429f37a-2017-10-20T100000.000Z
      reference_title: "NHS / Nance-Horan syndrome (Definitive)"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "NHS | HGNC:7820 | Nance-Horan syndrome | MONDO:0010545 | XL | Definitive"
      explanation: ClinGen gene-disease validity record classifying NHS in Nance-Horan syndrome as Definitive.
  evidence:
  - reference: PMID:14564667
    reference_title: "Mutations in a novel gene, NHS, cause the pleiotropic effects of Nance-Horan syndrome, including severe congenital cataract, dental anomalies, and mental retardation."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "have identified protein-truncating mutations in a novel gene, which we have called \"NHS,\" in five families."
    explanation: Original identification of truncating NHS mutations in five Nance-Horan syndrome families.
  - reference: PMID:15466011
    reference_title: "Identification of the gene for Nance-Horan syndrome (NHS)."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "A novel gene NHS, with no known function, was identified as causative for NHS. Protein truncating mutations were detected in all three NHS pedigrees"
    explanation: Independent identification of NHS as the causal gene.
  - reference: PMID:19414485
    reference_title: "X-linked cataract and Nance-Horan syndrome are allelic disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "identifying four novel protein truncation mutations and a novel large deletion encompassing the majority of the NHS gene, all leading to no functional protein"
    explanation: Truncating mutations and a large deletion in seven syndromic families, all predicted to abolish the protein.
  - reference: PMID:28922055
    reference_title: "Nance-Horan syndrome in females due to a balanced X;1 translocation that disrupts the NHS gene: Familial case report and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "The cytogenetic and molecular analyses demonstrated a 46,X,t(X;1)(p22.13;q22) karyotype in each of them."
    explanation: A balanced X;1 translocation with its breakpoint at Xp22.13 disrupting NHS, showing gene disruption by structural rearrangement as an allelic mechanism.
  - reference: PMID:30642278
    reference_title: "Whole exome sequencing identified a novel truncation mutation in the NHS gene associated with Nance-Horan syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "NHS mutations in the NHS-affected individuals typically result in premature truncation of the protein."
    explanation: Literature review within a family report summarising protein truncation as the usual allele class.
  variants:
  - name: NHS c.115C>T p.(Gln39Ter)
    type: single nucleotide variant
    clinical_significance: PATHOGENIC
    description: >-
      Exon 1 nonsense variant segregating in a four-generation Asian Indian
      family with eight affected males, who had severe ocular but mild to
      moderate non-ocular features.
    evidence:
    - reference: PMID:15623749
      reference_title: "Truncating mutation in the NHS gene: phenotypic heterogeneity of Nance-Horan syndrome in an asian Indian family."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "revealed a truncating mutation 115C-->T in exon 1, resulting in conversion of glutamine to stop codon (Q39X), but was not observed in unaffected individuals and control subjects"
      explanation: Segregation of the Q39X nonsense allele with disease in affected males and carrier females.
  - name: NHS p.(Arg373Ter)
    type: single nucleotide variant
    clinical_significance: PATHOGENIC
    description: >-
      Recurrent nonsense variant reported in unrelated families from different
      countries.
    evidence:
    - reference: PMID:18949062
      reference_title: "Novel causative mutations in patients with Nance-Horan syndrome and altered localization of the mutant NHS-A protein isoform."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "each of the two other patients carried two previously reported mutations (R373X and R879X)"
      explanation: R373X recurs as a previously reported truncating allele in a new patient series.
    - reference: PMID:31755796
      reference_title: "Great clinical variability of Nance Horan syndrome due to deleterious NHS mutations in two unrelated Spanish families."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Two pathogenic variants were found in the NHS gene: a nonsense mutation (p.Arg373X) and a frameshift mutation (p.His669ProfsX5)."
      explanation: The same nonsense allele in an unrelated Spanish family.
  - name: Xp22.13 microdeletions including NHS
    type: copy number variation
    clinical_significance: PATHOGENIC
    description: >-
      Contiguous deletions removing NHS together with neighbouring genes such
      as REPS2, SCML1 and RAI2 cause the classical syndrome, and larger
      deletions can add features attributable to the co-deleted genes.
    evidence:
    - reference: PMID:35122698
      reference_title: "Identification of a novel microdeletion causative of Nance-Horan syndrome."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "With the evolution of array-CGH technology, a total of five kindreds with NHS have been reported in the medical literature with microdeletions encompassing the NHS gene rather than sequencing variants."
      explanation: Summarises microdeletions as a recurrent class of Nance-Horan syndrome alleles.
    - reference: PMID:36370055
      reference_title: "Nance-Horan syndrome pedigree due to a novel microdeletion and skewed X chromosome inactivation."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The microdeletion contains the REPS2 and NHS genes and was inherited from a phenotypically normal mother."
      explanation: A heterozygous Xp22.13 microdeletion removing NHS in an affected female.
    - reference: PMID:20882036
      reference_title: "Identification of a microdeletion at Xp22.13 in a Taiwanese family presenting with Nance-Horan syndrome."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The deleted region encompasses the REPS2, NHS, SCML1 and RAI2 genes, and was transmitted from their carrier mother who presented only mild cataract."
      explanation: A familial Xp22.13 microdeletion including NHS in two affected brothers, with mild expression in the carrier mother.
pathophysiology:
- name: NHS Loss of Function
  description: >-
    Truncating variants, deletions and gene-disrupting rearrangements leave no
    functional NHS protein. NHS is expressed in a temporally and spatially
    regulated pattern in the developing eye, teeth, brain and craniofacial
    region, which is where its loss produces the syndrome. NHS has no enzymatic
    activity and no GO molecular function annotation; its known activity is
    binding, through its WAVE homology domain, the WAVE regulatory complex
    subunits that it assembles into a WAVE shell complex (evidence on the
    downstream node Loss of NHS WAVE Shell Complex), which is the function bound
    here as decreased.
  biological_scale: MOLECULAR
  genes:
  - preferred_term: NHS
    term:
      id: hgnc:7820
      label: NHS
  molecular_functions:
  - preferred_term: WAVE regulatory complex subunit binding
    term:
      id: GO:0044877
      label: protein-containing complex binding
    modifier: DECREASED
  evidence:
  - reference: CGGV:assertion_a7f57ca3-efb2-4333-9ae1-732aa429f37a-2017-10-20T100000.000Z
    reference_title: "NHS / Nance-Horan syndrome (Definitive)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "The mechanism of pathogenicity is loss of function."
    explanation: ClinGen curation states loss of function as the disease mechanism.
  - reference: PMID:41236159
    reference_title: "Nance-Horan Syndrome: Further Delineation of the Affected Male and the Female Carrier Phenotypes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "It is caused by deleterious loss of function variants or deletions involving the NHS gene at Xp22.13."
    explanation: Recent cohort study summarising the allelic basis as loss of function.
  downstream:
  - target: Loss of NHS-A at Epithelial Tight Junctions
    causal_link_type: DIRECT
    description: >-
      Truncated NHS-A protein fails to reach the cell periphery where the
      wild-type isoform associates with ZO-1.
    evidence:
    - reference: PMID:18949062
      reference_title: "Novel causative mutations in patients with Nance-Horan syndrome and altered localization of the mutant NHS-A protein isoform."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "All three mutant proteins failed to localize to the cellular periphery in epithelial cells and instead were found in the cytoplasm."
      explanation: Patient-derived truncating mutations expressed in epithelial cells mislocalize NHS-A away from the junctional periphery.
  - target: Loss of NHS WAVE Shell Complex
    causal_link_type: DIRECT
    description: >-
      Without NHS, its N-terminal WAVE homology domain no longer assembles the
      WAVE shell complex, and C-terminal truncations reduce NHS function in
      the same assay.
    evidence:
    - reference: PMID:42595116
      reference_title: "The Nance-Horan syndrome protein NHS regulates cell migration persistence by organizing WAVE and N-WASP nucleation-promoting factor complexes."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "Patient mutations resulting in NHS proteins truncated at their C-terminus also reduced the ability of NHS i1 to rescue migration persistence."
      explanation: Patient truncations impair the WHD-containing isoform's cellular function.
  - target: Mosaic NHS Expression in Heterozygous Females
    causal_link_type: DIRECT
    description: >-
      In heterozygous females, X-inactivation leaves a mixture of cells
      expressing the normal or the mutant allele, and skewing sets how much
      functional NHS remains.
    evidence:
    - reference: PMID:28922055
      reference_title: "Nance-Horan syndrome in females due to a balanced X;1 translocation that disrupts the NHS gene: Familial case report and review of the literature."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The mother had a preferential inactivation of the normal X chromosome; expression analysis did not detect any mRNA isoform of NHS."
      explanation: Skewed inactivation of the normal X abolished NHS expression in an affected heterozygous female.
  - target: Abnormal Ocular Development
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:14564667
      reference_title: "Mutations in a novel gene, NHS, cause the pleiotropic effects of Nance-Horan syndrome, including severe congenital cataract, dental anomalies, and mental retardation."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "We found a complex pattern of temporally and spatially regulated expression, which, together with the pleiotropic features of NHS, suggests that this gene has key functions in the regulation of eye, tooth, brain, and craniofacial development."
      explanation: Developmental expression in the mouse eye, together with the human phenotype, places NHS in eye development.
  - target: Abnormal Odontogenesis
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:14564667
      reference_title: "Mutations in a novel gene, NHS, cause the pleiotropic effects of Nance-Horan syndrome, including severe congenital cataract, dental anomalies, and mental retardation."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "We found a complex pattern of temporally and spatially regulated expression, which, together with the pleiotropic features of NHS, suggests that this gene has key functions in the regulation of eye, tooth, brain, and craniofacial development."
      explanation: Developmental expression places NHS in tooth development; the cellular intermediates are not established.
  - target: Craniofacial Dysmorphogenesis
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:14564667
      reference_title: "Mutations in a novel gene, NHS, cause the pleiotropic effects of Nance-Horan syndrome, including severe congenital cataract, dental anomalies, and mental retardation."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "We found a complex pattern of temporally and spatially regulated expression, which, together with the pleiotropic features of NHS, suggests that this gene has key functions in the regulation of eye, tooth, brain, and craniofacial development."
      explanation: Developmental expression places NHS in craniofacial development; the cellular intermediates are not established.
  - target: Abnormal Brain Development
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:19447104
      reference_title: "NHS-A isoform of the NHS gene is a novel interactor of ZO-1."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "Immunolabelling of developing mouse with the anti-NHS antibody that detects both isoforms revealed the protein in the developing head including the eye and brain."
      explanation: NHS protein is present in the developing brain, consistent with a neurodevelopmental role.
  - target: Short metacarpal
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      Brachymetacarpalia is part of the classical description; no skeletal
      mechanism for NHS has been studied.
- name: Loss of NHS-A at Epithelial Tight Junctions
  description: >-
    The NHS-A isoform associates with the apical membrane of epithelial cells,
    co-localises and co-immunoprecipitates with the tight junction protein
    ZO-1, and in the developing lens is restricted to the lens epithelium.
    Loss or mislocalisation of NHS-A removes it from these junctions.
  biological_scale: CELLULAR
  cell_types:
  - preferred_term: lens epithelial cell
    term:
      id: CL:0002224
      label: lens epithelial cell
  cellular_components:
  - preferred_term: tight junction
    term:
      id: GO:0070160
      label: tight junction
  evidence:
  - reference: PMID:16675532
    reference_title: "Nance-Horan syndrome protein, NHS, associates with epithelial cell junctions."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "We show that the endogenous and exogenous NHS-A isoform localizes to the cell membrane of mammalian cells in a cell-type-dependent manner and that it co-localizes with the tight junction (TJ) protein ZO-1 in the apical aspect of cell membrane in epithelial cells."
    explanation: Establishes the junctional localisation of NHS-A that is lost in disease.
  - reference: PMID:19447104
    reference_title: "NHS-A isoform of the NHS gene is a novel interactor of ZO-1."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "it immunoprecipitates with the tight junction protein ZO-1 in MDCK (Madin Darby Canine Kidney) epithelial cells and in neonatal rat lens"
    explanation: NHS-A physically associates with ZO-1 in epithelial cells and lens.
  - reference: PMID:16675532
    reference_title: "Nance-Horan syndrome protein, NHS, associates with epithelial cell junctions."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "In the developing mammalian lens, we found continuous expression of NHS that became restricted to the lens epithelium in pre- and postnatal lens."
    explanation: Places NHS in the lens epithelium, the cell population relevant to cataract.
  downstream:
  - target: Lens Epithelial Intercellular Contact Disruption
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      Proposed, not demonstrated in lens tissue: loss of junctional NHS-A is
      expected to weaken cell-cell contacts in the lens epithelium.
    evidence:
    - reference: PMID:18949062
      reference_title: "Novel causative mutations in patients with Nance-Horan syndrome and altered localization of the mutant NHS-A protein isoform."
      supports: SUPPORT
      evidence_source: IN_VITRO
      directness: INDIRECT
      snippet: "The mislocalization of the mutant NHS-A protein, revealed by mutation analysis, is expected to adversely affect cell-cell junctions in epithelial cells such as the lens epithelium, which may explain cataractogenesis in Nance-Horan syndrome patients."
      explanation: The authors infer junctional disruption in the lens epithelium from mislocalisation in cultured cells.
- name: Loss of NHS WAVE Shell Complex
  description: >-
    The N-terminus of the long NHS isoforms is a functional WAVE homology
    domain that binds ABI, HSPC300 (BRK1), NCKAP1 (Nap1) and CYFIP (Sra1), the
    WAVE regulatory complex subunits other than WAVE itself, forming a WAVE
    shell complex. Without NHS, ABI1 no longer associates with the WIPF2/N-WASP
    complex.
  biological_scale: MOLECULAR
  cellular_components:
  - preferred_term: SCAR complex
    term:
      id: GO:0031209
      label: SCAR complex
  evidence:
  - reference: PMID:20332100
    reference_title: "The Nance-Horan syndrome protein encodes a functional WAVE homology domain (WHD) and is important for co-ordinating actin remodelling and maintaining cell morphology."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "The N-terminus of isoforms NHS-A and NHS-1A, implicated in the pathogenesis of NHS, have a functional WAVE homology domain that interacts with the Abi protein family, haematopoietic stem/progenitor cell protein 300 (HSPC300), Nap1 and Sra1."
    explanation: Defines the WAVE homology domain and its WAVE regulatory complex partners.
  - reference: PMID:42595116
    reference_title: "The Nance-Horan syndrome protein NHS regulates cell migration persistence by organizing WAVE and N-WASP nucleation-promoting factor complexes."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "we identified as major NHS partners all subunits of the WAVE Regulatory Complex (WRC) except WAVE subunits themselves, indicating that the WHD of NHS assembles a WAVE Shell Complex (WSC)."
    explanation: Proteomics of NHS isoform 1 identifies the WAVE shell complex.
  downstream:
  - target: Disorganised Actin Cytoskeleton and Lamellipodial Dynamics
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      The NHS WAVE shell complex remodels nucleation-promoting factor
      complexes that feed Arp2/3-dependent branched actin assembly.
    evidence:
    - reference: PMID:42595116
      reference_title: "The Nance-Horan syndrome protein NHS regulates cell migration persistence by organizing WAVE and N-WASP nucleation-promoting factor complexes."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "These results suggest that NHS controls cell migration by remodeling NPF complexes and their higher order assembly."
      explanation: Links the NHS-organised complexes to the cellular actin and migration phenotype.
- name: Disorganised Actin Cytoskeleton and Lamellipodial Dynamics
  description: >-
    NHS knockdown disrupts the actin cytoskeleton and the circumferential actin
    ring, increases cell spreading and lamellipod formation, and NHS knockout
    reduces the persistence of cell migration. These are cultured-cell
    phenotypes; the corresponding defect in developing lens, tooth or brain
    tissue has not been shown.
  biological_scale: CELLULAR
  biological_processes:
  - preferred_term: actin cytoskeleton organization
    term:
      id: GO:0030036
      label: actin cytoskeleton organization
    modifier: ABNORMAL
  - preferred_term: regulation of lamellipodium assembly
    term:
      id: GO:0010591
      label: regulation of lamellipodium assembly
    modifier: ABNORMAL
  - preferred_term: cell migration
    term:
      id: GO:0016477
      label: cell migration
    modifier: DECREASED
  evidence:
  - reference: PMID:20332100
    reference_title: "The Nance-Horan syndrome protein encodes a functional WAVE homology domain (WHD) and is important for co-ordinating actin remodelling and maintaining cell morphology."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "NHS knockdown resulted in the disruption of the actin cytoskeleton."
    explanation: Direct cellular consequence of NHS depletion.
  - reference: PMID:20332100
    reference_title: "The Nance-Horan syndrome protein encodes a functional WAVE homology domain (WHD) and is important for co-ordinating actin remodelling and maintaining cell morphology."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "We show that NHS controls cell morphology by maintaining the integrity of the circumferential actin ring and controlling lamellipod formation."
    explanation: NHS is required to maintain cortical actin organisation and restrain lamellipodia.
  - reference: PMID:42595116
    reference_title: "The Nance-Horan syndrome protein NHS regulates cell migration persistence by organizing WAVE and N-WASP nucleation-promoting factor complexes."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "NHS KO cells displayed reduced migration persistence, a phenotype that was fully rescued by the long isoform 1 (i1) that contains an N-terminal WAVE Homology Domain (WHD), but only partially rescued by the short isoform two (i2), which does not."
    explanation: Knockout reduces migration persistence, rescued by the WHD-containing isoform.
  downstream:
  - target: Abnormal Ocular Development
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      Proposed link from defective actin remodelling to developmental
      morphogenesis; not demonstrated in vivo.
    evidence:
    - reference: PMID:20332100
      reference_title: "The Nance-Horan syndrome protein encodes a functional WAVE homology domain (WHD) and is important for co-ordinating actin remodelling and maintaining cell morphology."
      supports: SUPPORT
      evidence_source: IN_VITRO
      directness: INDIRECT
      snippet: "We suggest that NHS orchestrates actin regulatory protein function in response to signalling events during development."
      explanation: Authors' proposal that the actin-regulatory function operates during development.
- name: Lens Epithelial Intercellular Contact Disruption
  description: >-
    Weakened intercellular contacts in the lens epithelium are the proposed
    tissue-level basis of the dense congenital cataract. The mouse Xcat model
    shows that the defect acts within lens cells.
  biological_scale: TISSUE
  locations:
  - preferred_term: epithelium of lens
    term:
      id: UBERON:0001803
      label: epithelium of lens
  evidence:
  - reference: PMID:16675532
    reference_title: "Nance-Horan syndrome protein, NHS, associates with epithelial cell junctions."
    supports: SUPPORT
    evidence_source: IN_VITRO
    directness: INDIRECT
    snippet: "This study suggests that disturbances in intercellular contacts underlie cataractogenesis in the Nance-Horan syndrome."
    explanation: The authors' inference from NHS-A junctional localisation; not directly measured in patient lens.
  - reference: PMID:2272505
    reference_title: "Genetic localization and phenotypic expression of X-linked cataract (Xcat) in Mus musculus."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "the site of gene action for the Xcat locus is suggested to be endogenous to the lens cells"
    explanation: Variegated lens opacity in heterozygous Xcat mice places the gene's action inside lens cells.
  downstream:
  - target: Congenital cataract
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:16675532
      reference_title: "Nance-Horan syndrome protein, NHS, associates with epithelial cell junctions."
      supports: SUPPORT
      evidence_source: IN_VITRO
      directness: INDIRECT
      snippet: "NHS is the first gene localized at TJs that has been implicated in congenital cataracts."
      explanation: Ties the tight-junction role of NHS to the congenital cataract phenotype.
- name: Abnormal Ocular Development
  description: >-
    Beyond the lens, NHS loss is associated with a small cornea and eye and
    with maldevelopment of the anterior chamber angle, which predisposes to
    childhood glaucoma, and retinal cystoid degeneration has been described on
    histopathology.
  biological_scale: TISSUE
  biological_processes:
  - preferred_term: camera-type eye development
    term:
      id: GO:0043010
      label: camera-type eye development
    modifier: ABNORMAL
  evidence:
  - reference: PMID:19941417
    reference_title: "Ophthalmic pathology of Nance-Horan syndrome: case report and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We report a new pathological finding of severe retinal cystoid degeneration in this NHS patient and confirm abnormal development of the anterior chamber angle structure."
    explanation: Ocular histopathology showing developmental anomaly of the anterior chamber angle and retinal degeneration.
  downstream:
  - target: Microcornea
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Microphthalmia
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Childhood glaucoma
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: Abnormal anterior chamber angle development underlies the infantile glaucoma.
    evidence:
    - reference: PMID:19941417
      reference_title: "Ophthalmic pathology of Nance-Horan syndrome: case report and review of the literature."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Classic and novel ocular pathological findings of a young male with NHS are described, including congenital cataracts, infantile glaucoma, scleral staphyloma, and severe retinal cystoid degeneration."
      explanation: Infantile glaucoma documented together with the angle anomaly in the same eye.
  - target: Retinal degeneration
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
- name: Abnormal Odontogenesis
  description: >-
    NHS loss alters tooth number and crown shape in both dentitions, producing
    screwdriver-shaped incisors, bud-shaped molars, supernumerary teeth
    (including mesiodens) and, less often, tooth agenesis.
  biological_scale: TISSUE
  biological_processes:
  - preferred_term: odontogenesis
    term:
      id: GO:0042476
      label: odontogenesis
    modifier: ABNORMAL
  evidence:
  - reference: PMID:27616609
    reference_title: "Nance-Horan syndrome-The oral perspective on a rare disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The only consistent and very clear dental aberration was alterations in the tooth morphology that is screwdriver-shaped incisors and bud molars being most pronounced in the permanent dentition, but were also present in the primary dentition."
    explanation: Dental case series and literature review defining the characteristic dental developmental anomaly.
  downstream:
  - target: Screwdriver-shaped incisors
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Bud-shaped molars
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Supernumerary teeth
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Mesiodens
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Diastema
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Tooth agenesis
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
- name: Craniofacial Dysmorphogenesis
  description: >-
    Affected males and many carrier females share a recognisable facial
    gestalt with a long narrow face, a prominent or bulbous nose, mandibular
    prognathism and large anteverted ears.
  biological_scale: TISSUE
  evidence:
  - reference: PMID:22229851
    reference_title: "Phenotype-genotype correlation in potential female carriers of X-linked developmental cataract (Nance-Horan syndrome)."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "All seven affected family members had congenital or infantile cataract and facial dysmorphism (long face, bulbous nose, abnormal dentition)."
    explanation: Facial dysmorphism in all affected members of a genotyped family.
  downstream:
  - target: Long face
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Bulbous nose
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Prominent nose
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Anteverted ears
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Mandibular prognathia
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
- name: Abnormal Brain Development
  description: >-
    About a third of affected males have intellectual disability, usually mild
    to moderate, sometimes with autistic traits; regression with corpus
    callosum anomalies and leukoencephalopathy has been reported in a single
    boy. How NHS loss affects brain development is not known.
  biological_scale: TISSUE
  evidence:
  - reference: PMID:9268101
    reference_title: "Mental retardation in Nance-Horan syndrome: clinical and neuropsychological assessment in four families."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Our study confirms that mental retardation (MR) can be a major component of the NHS."
    explanation: Clinical and neuropsychological assessment establishing the neurodevelopmental component.
  - reference: PMID:34573171
    reference_title: "Prominent and Regressive Brain Developmental Disorders Associated with Nance-Horan Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The affected boy from this family presented a late regression of cognitive, motor, language, and adaptive skills, as well as broad behavioral anomalies."
    explanation: Single-family report of neurodevelopmental regression, with corpus callosum anomalies and leukoencephalopathy on imaging.
  downstream:
  - target: Intellectual disability
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Autistic behavior
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
- name: Mosaic NHS Expression in Heterozygous Females
  description: >-
    In a heterozygous female each cell expresses either the normal or the
    mutant NHS allele according to which X is active. Random inactivation
    usually yields a mild phenotype, classically posterior Y-sutural lens
    opacities; skewed inactivation of the normal X, or of the normal X in a
    balanced X-autosome translocation carrier, produces a male-like
    presentation. This is X-inactivation mosaicism of a germline allele, not
    post-zygotic somatic mosaicism.
  biological_scale: CELLULAR
  genes:
  - preferred_term: NHS
    term:
      id: hgnc:7820
      label: NHS
  evidence:
  - reference: PMID:36370055
    reference_title: "Nance-Horan syndrome pedigree due to a novel microdeletion and skewed X chromosome inactivation."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The variability among female carriers presumably results from nonrandom X chromosome inactivation."
    explanation: Skewed X-inactivation with reduced NHS expression in an affected female carrier of an NHS microdeletion.
  - reference: PMID:2272505
    reference_title: "Genetic localization and phenotypic expression of X-linked cataract (Xcat) in Mus musculus."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "A variegated pattern of lens opacity was evident in female heterozygotes."
    explanation: Variegated lens opacity in heterozygous Xcat mice reflects X-inactivation mosaicism within the lens.
  downstream:
  - target: Posterior Y-sutural cataract
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:22229851
      reference_title: "Phenotype-genotype correlation in potential female carriers of X-linked developmental cataract (Nance-Horan syndrome)."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Lens opacities centered around the posterior Y-suture in the context of certain facial features were sensitive and specific clinical signs of carrier status for NHS mutation in asymptomatic females."
      explanation: Posterior Y-sutural opacity is the characteristic lens expression of heterozygosity.
phenotypes:
- name: Congenital cataract
  category: Ophthalmologic
  description: >-
    Dense bilateral congenital cataracts, typically central, are present in
    affected males and lead to profound visual loss. They can be detected
    prenatally by ultrasound.
  phenotype_term:
    preferred_term: Congenital cataract
    term:
      id: HP:0000519
      label: Developmental cataract
  diagnostic: true
  evidence:
  - reference: PMID:1969135
    reference_title: "Mapping X-linked ophthalmic diseases. IV. Provisional assignment of the locus for X-linked congenital cataracts and microcornea (the Nance-Horan syndrome) to Xp22.2-p22.3."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The Nance-Horan syndrome (NHS) is an infrequent X-linked disorder typified by dense congenital central cataracts, microcornea, anteverted and simplex pinnae, brachymetacarpalia, and numerous dental anomalies."
    explanation: Classical clinical definition from five multigenerational kindreds.
  - reference: PMID:22229851
    reference_title: "Phenotype-genotype correlation in potential female carriers of X-linked developmental cataract (Nance-Horan syndrome)."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "All seven affected family members had congenital or infantile cataract and facial dysmorphism (long face, bulbous nose, abnormal dentition)."
    explanation: Congenital or infantile cataract in every affected member of a genotyped family.
  - reference: PMID:17451191
    reference_title: "Prenatal detection of congenital bilateral cataract leading to the diagnosis of Nance-Horan syndrome in the extended family."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Ultrasound demonstrated fetal bilateral congenital cataract."
    explanation: Bilateral cataract is already present before birth in an NHS-mutation fetus.
  sequelae:
  - target: Visual impairment
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:23566852
      reference_title: "A Turkish family with Nance-Horan Syndrome due to a novel mutation."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Nance-Horan Syndrome (NHS) is a rare X-linked syndrome characterized by congenital cataract which leads to profound vision loss"
      explanation: States that the congenital cataract leads to profound vision loss.
  - target: Nystagmus
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: Nystagmus develops in the setting of early visual deprivation from dense congenital cataract.
  - target: Strabismus
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: Strabismus accompanies the visual deprivation of dense congenital cataract.
- name: Posterior Y-sutural cataract
  category: Ophthalmologic
  description: >-
    The characteristic finding in heterozygous females: lens opacities centred
    on the posterior Y-suture, usually with preserved vision. Together with the
    facial features it is a sensitive and specific clinical sign of carrier
    status.
  phenotype_term:
    preferred_term: Posterior Y-sutural cataract
    term:
      id: HP:0008031
      label: Posterior Y-sutural cataract
  evidence:
  - reference: PMID:22229851
    reference_title: "Phenotype-genotype correlation in potential female carriers of X-linked developmental cataract (Nance-Horan syndrome)."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Four had posterior Y-suture centered lens opacities; these four also exhibited the facial dysmorphism of the seven affected family members."
    explanation: Posterior Y-sutural opacities in heterozygous females carrying the familial NHS mutation.
  - reference: PMID:29402928
    reference_title: "A novel small deletion in the NHS gene associated with Nance-Horan syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "One female carrier displayed lens opacities centered on the posterior Y-suture in both eyes, as well as mild dental abnormalities."
    explanation: Independent family with the same carrier lens finding.
- name: Microcornea
  category: Ophthalmologic
  description: Small corneal diameter accompanies the cataract in affected males and is sometimes the only ocular sign in carrier females.
  phenotype_term:
    preferred_term: Microcornea
    term:
      id: HP:0000482
      label: Microcornea
  evidence:
  - reference: PMID:9268101
    reference_title: "Mental retardation in Nance-Horan syndrome: clinical and neuropsychological assessment in four families."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Nance-Horan syndrome (NHS) is a rare X-linked condition comprising congenital cataract with microcornea, distinctive dental, and evocative facial anomalies."
    explanation: Microcornea is part of the core ocular definition.
  - reference: PMID:23566852
    reference_title: "A Turkish family with Nance-Horan Syndrome due to a novel mutation."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We describe two brothers who have the NHS phenotype and their carrier mother who had microcornea but not cataract."
    explanation: Microcornea without cataract in a heterozygous carrier.
- name: Microphthalmia
  category: Ophthalmologic
  phenotype_term:
    preferred_term: Microphthalmia
    term:
      id: HP:0000568
      label: Microphthalmia
  evidence:
  - reference: PMID:23566852
    reference_title: "A Turkish family with Nance-Horan Syndrome due to a novel mutation."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Microcornea, microphthalmia and mild or moderate mental retardation may accompany these features."
    explanation: Microphthalmia is an accompanying ocular feature.
- name: Nystagmus
  category: Ophthalmologic
  phenotype_term:
    preferred_term: Nystagmus
    term:
      id: HP:0000639
      label: Nystagmus
  evidence:
  - reference: PMID:35122698
    reference_title: "Identification of a novel microdeletion causative of Nance-Horan syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The clinical phenotype in males includes congenital cataracts, vision loss, microcornea, nystagmus, microphthalmia, glaucoma, screwdriver blade-shaped incisors, supernumerary maxillary incisors, diastema, delays, intellectual disability, and dysmorphic facies."
    explanation: Nystagmus is listed in the male phenotype.
- name: Strabismus
  category: Ophthalmologic
  phenotype_term:
    preferred_term: Strabismus
    term:
      id: HP:0000486
      label: Strabismus
  evidence:
  - reference: PMID:29042737
    reference_title: "Nance-Horan Syndrome: A Rare Case Report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ocular abnormalities such as congenital cataract, microcornea, microphthalmia and strabismus"
    explanation: Strabismus is among the ocular abnormalities of the syndrome.
- name: Childhood glaucoma
  category: Ophthalmologic
  phenotype_term:
    preferred_term: Infantile glaucoma
    term:
      id: HP:0001087
      label: Developmental glaucoma
  evidence:
  - reference: PMID:19941417
    reference_title: "Ophthalmic pathology of Nance-Horan syndrome: case report and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Classic and novel ocular pathological findings of a young male with NHS are described, including congenital cataracts, infantile glaucoma, scleral staphyloma, and severe retinal cystoid degeneration."
    explanation: Infantile glaucoma in a patient with NHS.
  - reference: PMID:35122698
    reference_title: "Identification of a novel microdeletion causative of Nance-Horan syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The clinical phenotype in males includes congenital cataracts, vision loss, microcornea, nystagmus, microphthalmia, glaucoma, screwdriver blade-shaped incisors, supernumerary maxillary incisors, diastema, delays, intellectual disability, and dysmorphic facies."
    explanation: Glaucoma is part of the reported male phenotype.
- name: Retinal degeneration
  category: Ophthalmologic
  description: Severe retinal cystoid degeneration was found on histopathology in one patient.
  phenotype_term:
    preferred_term: Retinal cystoid degeneration
    term:
      id: HP:0000546
      label: Retinal degeneration
  evidence:
  - reference: PMID:19941417
    reference_title: "Ophthalmic pathology of Nance-Horan syndrome: case report and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We report a new pathological finding of severe retinal cystoid degeneration in this NHS patient"
    explanation: Histopathological retinal cystoid degeneration in an NHS eye.
- name: Visual impairment
  category: Ophthalmologic
  phenotype_term:
    preferred_term: Profound visual impairment
    term:
      id: HP:0000505
      label: Visual impairment
  evidence:
  - reference: PMID:41236159
    reference_title: "Nance-Horan Syndrome: Further Delineation of the Affected Male and the Female Carrier Phenotypes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "bilateral congenital cataracts leading to profound vision loss"
    explanation: Profound vision loss is the main functional consequence of the cataract.
- name: Screwdriver-shaped incisors
  category: Dental
  description: >-
    Incisors with a screwdriver-blade crown, most pronounced in the permanent
    dentition but present in the primary dentition; with bud-shaped molars and
    congenital cataract, a strong clinical pointer to the diagnosis.
  phenotype_term:
    preferred_term: Screwdriver-shaped incisors
    term:
      id: HP:0006346
      label: Screwdriver-shaped incisors
  diagnostic: true
  evidence:
  - reference: PMID:27616609
    reference_title: "Nance-Horan syndrome-The oral perspective on a rare disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The combination of congenital cataract, screwdriwer-shaped incisors and bud-shaped molars is a strong clinical indication of Nance-Horan syndrome."
    explanation: Screwdriver-shaped incisors are a diagnostic dental hallmark (the source misspells screwdriver).
- name: Bud-shaped molars
  category: Dental
  description: >-
    Molars with tapered, bud-shaped crowns. HPO has no bud-molar term, and the
    dental literature on this syndrome recommends calling them bud molars
    rather than mulberry molars, so the general molar-morphology term is bound
    and the specific shape is carried in the preferred term.
  phenotype_term:
    preferred_term: Bud-shaped molars
    term:
      id: HP:0011070
      label: Abnormal molar morphology
  evidence:
  - reference: PMID:27616609
    reference_title: "Nance-Horan syndrome-The oral perspective on a rare disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In the description of molar morphology in NHS patients, it is recommended to use the term \"bud molar.\""
    explanation: Defines the molar anomaly and its preferred terminology.
- name: Supernumerary teeth
  category: Dental
  phenotype_term:
    preferred_term: Supernumerary teeth
    term:
      id: HP:0011069
      label: Supernumerary tooth
  evidence:
  - reference: PMID:27616609
    reference_title: "Nance-Horan syndrome-The oral perspective on a rare disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In addition, three patients had supernumerary teeth, and three had dental agenesis."
    explanation: Supernumerary teeth in three of seven patients in a dental case series.
  - reference: PMID:37221585
    reference_title: "Nance-Horan Syndrome: characterization of dental, clinical and molecular features in three new families."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "dental findings including Hutchinson incisors, supernumerary teeth, bud-shaped molars"
    explanation: Supernumerary teeth with the other characteristic dental findings in a genotyped proband.
- name: Mesiodens
  category: Dental
  description: Supernumerary maxillary central incisors (mesiodens) are reported in males and occasionally in carrier females.
  phenotype_term:
    preferred_term: Mesiodens
    term:
      id: HP:0011067
      label: Mesiodens
  evidence:
  - reference: PMID:6467651
    reference_title: "The Nance-Horan syndrome: a rare X-linked ocular-dental trait with expression in heterozygous females."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In one of these two families, the affected female is not only blind in one eye but reportedly had supernumerary central incisors (mesiodens) removed."
    explanation: Mesiodens in a severely affected heterozygous female.
- name: Diastema
  category: Dental
  phenotype_term:
    preferred_term: Diastema
    term:
      id: HP:0000699
      label: Diastema
  evidence:
  - reference: PMID:35122698
    reference_title: "Identification of a novel microdeletion causative of Nance-Horan syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The clinical phenotype in males includes congenital cataracts, vision loss, microcornea, nystagmus, microphthalmia, glaucoma, screwdriver blade-shaped incisors, supernumerary maxillary incisors, diastema, delays, intellectual disability, and dysmorphic facies."
    explanation: Diastema is part of the reported male dental phenotype.
- name: Tooth agenesis
  category: Dental
  phenotype_term:
    preferred_term: Tooth agenesis
    term:
      id: HP:0009804
      label: Tooth agenesis
  evidence:
  - reference: PMID:27616609
    reference_title: "Nance-Horan syndrome-The oral perspective on a rare disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In addition, three patients had supernumerary teeth, and three had dental agenesis."
    explanation: Dental agenesis in three of seven patients.
- name: Long face
  category: Craniofacial
  phenotype_term:
    preferred_term: Long face
    term:
      id: HP:0000276
      label: Long face
  evidence:
  - reference: PMID:22229851
    reference_title: "Phenotype-genotype correlation in potential female carriers of X-linked developmental cataract (Nance-Horan syndrome)."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "All seven affected family members had congenital or infantile cataract and facial dysmorphism (long face, bulbous nose, abnormal dentition)."
    explanation: Long face in all affected members of a genotyped family.
- name: Bulbous nose
  category: Craniofacial
  phenotype_term:
    preferred_term: Bulbous nose
    term:
      id: HP:0000414
      label: Bulbous nose
  evidence:
  - reference: PMID:22229851
    reference_title: "Phenotype-genotype correlation in potential female carriers of X-linked developmental cataract (Nance-Horan syndrome)."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "All seven affected family members had congenital or infantile cataract and facial dysmorphism (long face, bulbous nose, abnormal dentition)."
    explanation: Bulbous nose in all affected members of a genotyped family.
- name: Prominent nose
  category: Craniofacial
  phenotype_term:
    preferred_term: Prominent nose
    term:
      id: HP:0000448
      label: Prominent nose
  evidence:
  - reference: PMID:29042737
    reference_title: "Nance-Horan Syndrome: A Rare Case Report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "It is characterized by facial dysmorphism such as long face, prominent nose and mandibular prognathism"
    explanation: Prominent nose is part of the facial dysmorphism.
  - reference: PMID:30642278
    reference_title: "Whole exome sequencing identified a novel truncation mutation in the NHS gene associated with Nance-Horan syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "who presented with a long-narrow face, prominent nose and large anteverted pinnae ear"
    explanation: Prominent nose in a molecularly confirmed proband.
- name: Mandibular prognathia
  category: Craniofacial
  phenotype_term:
    preferred_term: Mandibular prognathism
    term:
      id: HP:0000303
      label: Mandibular prognathia
  evidence:
  - reference: PMID:29042737
    reference_title: "Nance-Horan Syndrome: A Rare Case Report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "It is characterized by facial dysmorphism such as long face, prominent nose and mandibular prognathism"
    explanation: Mandibular prognathism is part of the facial dysmorphism.
- name: Anteverted ears
  category: Craniofacial
  phenotype_term:
    preferred_term: Anteverted pinnae
    term:
      id: HP:0040080
      label: Anteverted ears
  evidence:
  - reference: PMID:1969135
    reference_title: "Mapping X-linked ophthalmic diseases. IV. Provisional assignment of the locus for X-linked congenital cataracts and microcornea (the Nance-Horan syndrome) to Xp22.2-p22.3."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The Nance-Horan syndrome (NHS) is an infrequent X-linked disorder typified by dense congenital central cataracts, microcornea, anteverted and simplex pinnae, brachymetacarpalia, and numerous dental anomalies."
    explanation: Anteverted pinnae are part of the classical definition.
  - reference: PMID:30642278
    reference_title: "Whole exome sequencing identified a novel truncation mutation in the NHS gene associated with Nance-Horan syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "who presented with a long-narrow face, prominent nose and large anteverted pinnae ear"
    explanation: Large anteverted pinnae in a molecularly confirmed proband.
- name: Short metacarpal
  category: Skeletal
  phenotype_term:
    preferred_term: Brachymetacarpalia
    term:
      id: HP:0010049
      label: Short metacarpal
  evidence:
  - reference: PMID:1969135
    reference_title: "Mapping X-linked ophthalmic diseases. IV. Provisional assignment of the locus for X-linked congenital cataracts and microcornea (the Nance-Horan syndrome) to Xp22.2-p22.3."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The Nance-Horan syndrome (NHS) is an infrequent X-linked disorder typified by dense congenital central cataracts, microcornea, anteverted and simplex pinnae, brachymetacarpalia, and numerous dental anomalies."
    explanation: Brachymetacarpalia is part of the classical definition.
- name: Intellectual disability
  category: Neurodevelopmental
  description: >-
    Present in about 30% of affected males, mostly mild or moderate and
    without motor delay, with intra- and interfamilial variability; it was not
    found in carrier females in the original neuropsychological study.
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Intellectual disability
    term:
      id: HP:0001249
      label: Intellectual disability
  evidence:
  - reference: PMID:9268101
    reference_title: "Mental retardation in Nance-Horan syndrome: clinical and neuropsychological assessment in four families."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Combining our data with those from the literature leads to a frequency of MR in NHS of around 30%. In most cases, MR is mild or moderate (80%) and not associated with motor delay."
    explanation: Pooled frequency of about 30% supports the FREQUENT band (30-79%) at its lower edge, and the severity distribution.
  - reference: PMID:9268101
    reference_title: "Mental retardation in Nance-Horan syndrome: clinical and neuropsychological assessment in four families."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "MR has intra- and inter-familial variability but does not appear to be expressed in carriers."
    explanation: Variability between and within families, and absence in carrier females.
  - reference: PMID:25091991
    reference_title: "Identification of a novel mutation in a Chinese family with Nance-Horan syndrome by whole exome sequencing."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    snippet: "Mental retardation was present in about 30% of the reported cases."
    explanation: Independent restatement of the roughly 30% frequency in the literature.
- name: Autistic behavior
  category: Neurodevelopmental
  phenotype_term:
    preferred_term: Autistic traits
    term:
      id: HP:0000729
      label: Autistic behavior
  evidence:
  - reference: PMID:9268101
    reference_title: "Mental retardation in Nance-Horan syndrome: clinical and neuropsychological assessment in four families."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Conversely, a profound mental handicap associated with autistic traits may be observed."
    explanation: Autistic traits accompany profound intellectual disability in some patients.
  - reference: PMID:37221585
    reference_title: "Nance-Horan Syndrome: characterization of dental, clinical and molecular features in three new families."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "P3 also had autistic and psychobehavioral features."
    explanation: Autistic features in a molecularly confirmed patient.
- name: Congenital heart defect
  category: Cardiovascular
  description: >-
    Congenital heart defects, including a ventricular septal defect, are
    reported in a minority of patients. No mechanism has been studied, so no
    causal edge is drawn to this phenotype.
  phenotype_term:
    preferred_term: Congenital heart defect
    term:
      id: HP:0001627
      label: Abnormal heart morphology
  evidence:
  - reference: PMID:34573171
    reference_title: "Prominent and Regressive Brain Developmental Disorders Associated with Nance-Horan Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "NHS is characterized by congenital cataracts, dental anomalies, and distinctive facial features, and a proportion of the affected individuals also present intellectual disability and congenital cardiopathies."
    explanation: Congenital cardiopathies are reported in a proportion of patients.
  - reference: PMID:37221585
    reference_title: "Nance-Horan Syndrome: characterization of dental, clinical and molecular features in three new families."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "index (P2) presenting with global developmental delay, microphthalmia, cataracts, and ventricular septal defect"
    explanation: A ventricular septal defect in a patient with a deletion including NHS and 21 other genes, so attribution to NHS alone is uncertain.
diagnosis:
- name: Molecular genetic testing of NHS
  diagnosis_term:
    preferred_term: genetic testing
    term:
      id: NCIT:C15709
      label: Genetic Testing
  description: >-
    Sequencing of NHS (as a gene panel or exome) confirms the diagnosis. It is
    recommended for familial bilateral pediatric cataract, because dental and
    neurodevelopmental features can take years to appear and families are
    otherwise counselled as having isolated cataract.
  evidence:
  - reference: PMID:39858638
    reference_title: "Genotype-Phenotype Correlations of Nance-Horan Syndrome in Male and Female Carriers of a Novel Variant."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "This reinforces the importance of genetic testing of bilateral familial pediatric cataracts, especially since systemic features such as dental anomalies and intellectual disability may take years before they develop."
    explanation: A family first diagnosed with isolated cataract was recognised as Nance-Horan syndrome only after sequencing.
  - reference: PMID:40868138
    reference_title: "Genetic Landscape of Congenital Cataracts in a Swiss Cohort: Addressing Diagnostic Oversights in Nance-Horan Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "NHS remains underdiagnosed due to its variable expressivity and the late manifestation of systemic features, often leading to misclassification as isolated CC."
    explanation: Exome sequencing of a congenital cataract cohort identified NHS cases misclassified as isolated cataract.
- name: Copy number and cytogenetic analysis
  diagnosis_term:
    preferred_term: chromosomal microarray analysis
    term:
      id: NCIT:C18477
      label: Microarray Analysis
  description: >-
    When NHS sequencing is negative, chromosomal microarray detects
    microdeletions including NHS, and karyotype or FISH detects balanced
    X-autosome translocations that disrupt NHS, particularly in affected
    females.
  evidence:
  - reference: PMID:35122698
    reference_title: "Identification of a novel microdeletion causative of Nance-Horan syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A chromosomal microarray (CMA) was performed and revealed a 1.83-Mb interstitial microdeletion at Xp22.2p22.13"
    explanation: Chromosomal microarray identified the causal NHS-containing deletion.
  - reference: PMID:34620209
    reference_title: "Allelic and dosage effects of NHS in X-linked cataract and Nance-Horan syndrome: a family study and literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "justifies consideration of karyotype and fluorescence in situ hybridization (FISH) analysis for female patients with familial NHS if single-gene analysis of NHS is negative"
    explanation: Recommends cytogenetic analysis for sequence-negative affected females.
- name: Dental examination
  diagnosis_term:
    preferred_term: dental examination
    term:
      id: NCIT:C158323
      label: Dental Examination
  description: >-
    The combination of screwdriver-shaped incisors and bud molars is
    distinctive, so a dental examination can point to the diagnosis in a child
    with congenital cataract, and dentists may be the first to suspect it.
  evidence:
  - reference: PMID:27616609
    reference_title: "Nance-Horan syndrome-The oral perspective on a rare disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "a dental examination as a part of the diagnostic process may reveal distinct characteristics of the dental morphology, which could be of diagnostic value and facilitate an early diagnosis"
    explanation: Recommends dental examination as part of diagnosis.
- name: Ophthalmic examination of at-risk females
  diagnosis_term:
    preferred_term: eye examination
    term:
      id: NCIT:C38060
      label: Eye Examination
  description: >-
    Slit-lamp examination of female relatives for posterior Y-sutural lens
    opacities identifies likely carriers; opacities of other morphology are not
    a carrier sign.
  evidence:
  - reference: PMID:22229851
    reference_title: "Phenotype-genotype correlation in potential female carriers of X-linked developmental cataract (Nance-Horan syndrome)."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Lens opacities that did not have this characteristic morphology in a suspected female carrier were not a carrier sign, even in the context of her affected family members."
    explanation: Defines the specificity of the Y-sutural opacity for carrier detection.
treatments:
- name: Congenital cataract surgery
  description: >-
    Surgical removal of the dense congenital cataracts in infancy, followed by
    optical correction and amblyopia therapy, following the general management
    of infantile cataract. No Nance-Horan-specific surgical outcome study was
    found. Glaucoma after infant cataract surgery is common in general, so the
    glaucoma seen in this syndrome needs follow-up whether developmental or
    postoperative.
  treatment_term:
    preferred_term: cataract surgery
    term:
      id: NCIT:C157809
      label: Cataract Surgery
  therapeutic_modality: SURGERY
  target_phenotypes:
  - preferred_term: Congenital cataract
    term:
      id: HP:0000519
      label: Developmental cataract
  evidence:
  - reference: PMID:31317088
    reference_title: "Updates on managements of pediatric cataract."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: INDIRECT
    snippet: "For significant lens opacity that leads to a considerable risk of amblyopia, cataract surgery is recommended at 6 weeks of age for unilateral cataract and between 6 and 8 weeks of age for bilateral cases."
    explanation: General pediatric cataract guidance on surgical timing, applied to the bilateral congenital cataract of this syndrome; not a Nance-Horan-specific study.
  - reference: PMID:35307324
    reference_title: "Current management of infantile cataracts."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: INDIRECT
    snippet: "Better visual outcomes in operated eyes, however, are achieved in the setting of early presentation, bilateral infantile cataracts, absence of nystagmus or strabismus, and consistent amblyopia therapy."
    explanation: General infantile cataract review on the determinants of visual outcome after surgery.
  - reference: PMID:35307324
    reference_title: "Current management of infantile cataracts."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: INDIRECT
    snippet: "The most common complications of cataract surgery performed in infancy are visual axis opacification and, in about a third of patients, the long-term development of glaucoma."
    explanation: Supports postoperative glaucoma surveillance; a general infantile cataract figure, not measured in this syndrome.
- name: Dental management
  description: >-
    Dental care addresses supernumerary and malformed teeth, including
    extraction of supernumerary incisors.
  treatment_term:
    preferred_term: dental procedure
    term:
      id: NCIT:C38052
      label: Dental Procedure
  therapeutic_modality: SURGERY
  target_phenotypes:
  - preferred_term: Supernumerary teeth
    term:
      id: HP:0011069
      label: Supernumerary tooth
  evidence:
  - reference: PMID:15660094
    reference_title: "A previously unreported association between Nance-Horan syndrome and spontaneous dental abscesses."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "This case describes the management of a 9-year-old girl referred for the routine management of supernumerary teeth."
    explanation: Case report of dental management of supernumerary teeth in Nance-Horan syndrome.
- name: Educational support
  description: Awareness of intellectual disability guides educational planning for affected boys.
  treatment_term:
    preferred_term: educational intervention
    term:
      id: NCIT:C17874
      label: Educational Intervention
  therapeutic_modality: BEHAVIORAL
  target_phenotypes:
  - preferred_term: Intellectual disability
    term:
      id: HP:0001249
      label: Intellectual disability
  evidence:
  - reference: PMID:9268101
    reference_title: "Mental retardation in Nance-Horan syndrome: clinical and neuropsychological assessment in four families."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Awareness of MR in NHS may be of importance in the management of the patients, especially in terms of education."
    explanation: Recommends educational management for the intellectual disability component.
animal_models:
- name: Xcat mouse
  species: Mouse
  genotype: Xcat, a large insertion between exons 1 and 2 of Nhs
  publication: PMID:16357105
  description: >-
    The spontaneous X-linked cataract (Xcat) mouse carries an insertion
    between exons 1 and 2 of Nhs that abolishes the exon 1-containing isoform,
    leaving only the alternative exon 1A isoform, and reduces Nhs protein in
    lens fiber cells. Hemizygous males and homozygous females have fully
    penetrant cataract; heterozygous females show variegated lens opacity.
  modeled_mechanisms:
  - target: NHS Loss of Function
    relationship: PARTIALLY_RECAPITULATES
    fidelity: MODERATE
    model_scale: ORGANISM
    description: Isoform-selective loss of the exon 1 Nhs isoform causing congenital cataract.
    limitations: >-
      The allele removes one isoform rather than the whole protein, and the
      cited abstracts report only the lens phenotype; dental, craniofacial and
      neurodevelopmental features are not described.
    evidence:
    - reference: PMID:16357105
      reference_title: "Xcat, a novel mouse model for Nance-Horan syndrome inhibits expression of the cytoplasmic-targeted Nhs1 isoform."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "The insertion inhibits the expression of the Nhs1 isoform containing exon 1 and results in exclusive expression of the alternative isoform containing exon 1A."
      explanation: Defines the isoform-selective loss of function in the model.
    - reference: PMID:16357105
      reference_title: "Xcat, a novel mouse model for Nance-Horan syndrome inhibits expression of the cytoplasmic-targeted Nhs1 isoform."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "Inhibition of expression of the exon 1 containing isoform results in the abnormal phenotype of Xcat."
      explanation: Links the Nhs isoform loss to the cataract phenotype.
  - target: Mosaic NHS Expression in Heterozygous Females
    relationship: RECAPITULATES
    fidelity: MODERATE
    model_scale: TISSUE
    description: Heterozygous females show variegated lens opacity, the mouse counterpart of variable carrier expression.
    limitations: Mouse X-inactivation and lens growth differ from human, and Y-sutural localisation is not described.
    evidence:
    - reference: PMID:2272505
      reference_title: "Genetic localization and phenotypic expression of X-linked cataract (Xcat) in Mus musculus."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "Phenotypic expression in Xcat heterozygous females ranges from totally clear to totally opaque lenses."
      explanation: Variable heterozygous expression in the mouse model.
  evidence:
  - reference: PMID:2272505
    reference_title: "Genetic localization and phenotypic expression of X-linked cataract (Xcat) in Mus musculus."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "In hemizygous males and homozygous females penetrance is complete with only slight variation in the degree of expression."
    explanation: Fully penetrant cataract in hemizygous Xcat males.
📚

References & Deep Research

Deep Research

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Evaluations and curation notes (1)

Create: Nance-Horan_Syndrome · 2026-10-14T21:27:09Z · View source

New entry for Nance-Horan syndrome (MONDO:0010545), the X-linked disorder caused by loss of NHS (hgnc:7820). Content: X-linked inheritance bound to HP:0001417 with an explanation of heterozygous female expression; NHS genetic record with the ClinGen Definitive XL assertion and three variant records (Q39X, recurrent R373X, Xp22.13 microdeletions); a pathograph running from NHS loss of function through loss of junctional NHS-A (ZO-1 partner), loss of the WAVE shell complex and disorganised actin and lamellipodial dynamics, to lens epithelial contact disruption and to ocular, dental, craniofacial and brain developmental nodes, plus an X-inactivation node for heterozygous females; 24 HPO-bound phenotypes, 23 of them causally connected (congenital heart defect is left unconnected because no mechanism has been studied); four diagnostic approaches; three supportive treatments; and the Xcat mouse with two model-to-mechanism links. Isolated X-linked congenital cataract (cataract 40, MONDO:0010544) was kept out of this entry and its stub left in the queue: MONDO classifies it separately and the published CXN alleles alter NHS transcription rather than abolishing the protein (PMID:19414485). No GeneReviews chapter exists. The OpenScientist report (research/Nance-Horan_Syndrome-deep-research-openscientist.md) was used as a source of leads: 21 of 21 references resolved, none off topic; term validation flagged mislabelled CURIEs (for example HP:0006315 offered for screwdriver incisors, which is Solitary median maxillary central incisor; HP:0006346 was bound instead) and two obsolete terms (GO:0005913, CL:0000181), none of which were used; preflight-dr returned PASS (NHS mentioned 87 times, OMIM 302350 matches). Report citations not used: PMID:33149277 and PMID:30664714 (CYFIP2 disorders, a different disease, offered only as mechanistic analogy); PMID:23288986 (lens epithelial cell lines, not about NHS); PMID:30457727 (differential diagnosis of supernumerary teeth); PMID:36107778 (general intraocular lens versus aphakia review, no Nance-Horan content). Phenotypes the report listed but that were not added: ptosis and high myopia (no quotable source); hearing loss, axial hypotonia and foot contractures (seen only with a contiguous deletion of eight further genes, recorded in notes). PMID:42253502, a 2026 cell study proposing extracellular-matrix and mitochondrial mechanisms for two NHS variants, was read and not used because it is a single unreplicated overexpression study. Every snippet (99 of 99) verifies against the cached abstract text.

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Nance-Horan Syndrome: Comprehensive Disease Characteristics Report
openscientist-autonomous 21 citations 2026-10-14T21:20:01.233086

Nance-Horan Syndrome: Comprehensive Disease Characteristics Report

Disease: Nance-Horan Syndrome (NHS) MONDO ID: MONDO:0010545 · OMIM: 302350 · Orphanet: ORPHA:627 · Category: Mendelian (X-linked) Causal gene: NHS (Xp22.13)

Summary

Nance-Horan Syndrome (NHS) is an ultra-rare X-linked developmental disorder caused by loss-of-function variants and deletions in the NHS gene on chromosome Xp22.13 (OMIM 302350; MONDO:0010545; Orphanet ORPHA:627). In hemizygous males it produces a characteristic tetrad of bilateral dense congenital cataracts, dental anomalies (screwdriver-shaped incisors, mulberry molars, supernumerary teeth), facial dysmorphism, and — in ~30% — intellectual disability. Heterozygous female carriers show milder, more variable features, classically posterior Y-suture lens opacities with subtle facial and dental signs, driven by patterns of X-chromosome inactivation (XCI). The disorder is best characterized as X-linked semidominant (X-linked dominant with milder female expression).

Mechanistically, the NHS gene encodes a 1,630-amino-acid protein that is a founder member of a new protein family (NHS, NHSL1, NHSL2) and functions as a regulator of actin remodelling and cell morphology. Its N-terminus contains a functional WAVE homology domain (WHD) that binds the WAVE regulatory complex (WRC) components Abi, HSPC300, Nap1 (NCKAP1) and Sra1 (CYFIP1). The protein is strongly expressed in the cytoplasm of elongating lens fiber cells and in a complex spatiotemporal pattern across the developing eye, tooth, brain and craniofacial structures — explaining the pleiotropy. Loss of functional NHS protein (haploinsufficiency in females; hemizygous loss in males) disrupts actin-dependent cell morphology and lens fiber differentiation, producing the clinical phenotype. The Xcat mouse recapitulates the disease by abolishing the cytoplasmic (exon-1-containing) Nhs isoform.

There is no disease-modifying or gene-directed therapy. Management is symptomatic: early surgery for visually significant congenital cataracts (around 6–8 weeks for bilateral cases), aphakic optical correction, consistent amblyopia therapy, dental/orthodontic care, developmental support, and genetic counseling with cascade and prenatal/preimplantation testing. NHS is frequently underdiagnosed as isolated hereditary cataract because systemic features may take years to manifest; genetic testing of bilateral familial pediatric cataract is therefore central to diagnosis and family counseling.

Section 1 — Disease Information

Overview. Nance-Horan Syndrome is a rare X-linked developmental disorder whose cardinal manifestations are bilateral congenital cataracts, dental anomalies, dysmorphic facial features, and (in a subset) intellectual disability. It is caused by deleterious loss-of-function variants or deletions involving the NHS gene at Xp22.13 (PMID: 41236159): "It is caused by deleterious loss of function variants or deletions involving the NHS gene at Xp22.13. Heterozygous females often present with similar, but less severe features than affected males."

Key identifiers.

Resource Identifier
OMIM 302350
MONDO MONDO:0010545
Orphanet ORPHA:627 (prevalence < 1/1,000,000)
Gene (HGNC) NHS
Cytoband Xp22.13
ICD-10 Q13.8 / congenital cataract with syndromic features (no dedicated code)
MeSH Nance-Horan syndrome / "Cataract" + "Tooth Abnormalities"

Synonyms / alternative names. Nance-Horan syndrome; NHS; Cataract–dental syndrome; Mesiodens–cataract syndrome; X-linked cataract–dental syndrome. NHS is allelic with isolated X-linked congenital cataract (CXN).

Information source. The knowledge in this report is derived from aggregated disease-level resources (OMIM, Orphanet) and primary literature describing individual families/patients (case reports, cohort and mutation studies), not from a single EHR dataset.

Section 2 — Etiology

Primary cause — genetic. NHS is a monogenic X-linked disorder. The disease results from loss-of-function variants (frameshift, nonsense, splice, small insertions/deletions) and microdeletions in the NHS gene. Haploinsufficiency of NHS accounts for the majority of clinical symptoms (PMID: 36370055): "the haploinsufficiency of the NHS gene may account for the majority of clinical symptoms in the affected subjects. The variability among female carriers presumably results from nonrandom X chromosome inactivation."

Genetic risk factors. The only established risk factor is inheritance of a pathogenic NHS allele. Being male (hemizygous) confers full phenotypic expression; being a female carrier confers a milder, variable phenotype. No independent susceptibility loci or modifier genes outside the NHS locus have been established. Skewed (non-random) X-inactivation acts as a key modifier of severity in females.

Environmental risk factors. None established. NHS is a fully penetrant Mendelian disorder in males; there is no evidence that toxins, lifestyle, occupational exposure, or infection cause or trigger it.

Protective factors. No genetic or environmental protective factors are reported. In female carriers, favorably skewed XCI (preferentially silencing the mutant allele) is the nearest analog to a "protective" modifier, reducing phenotypic severity.

Gene–environment interactions. None established. The disorder is determined by the NHS genotype and X-inactivation, not by gene–environment interplay.

Section 3 — Phenotypes

Phenotypes are congenital/developmental in onset, predominantly stable (non-progressive) structural anomalies, with variable severity graded by sex and mutation mechanism. Males show the full spectrum; females are milder.

Phenotype Type Suggested HPO Frequency / notes
Bilateral congenital cataract Clinical sign / physical HP:0000519 (congenital cataract) Near-universal in males; cardinal feature
Microcornea Physical HP:0000482 Common
Microphthalmia Physical HP:0000568 Reported
Nystagmus Clinical sign HP:0000639 Common; worsens visual prognosis
Strabismus Clinical sign HP:0000486 Common
Congenital ptosis Physical HP:0000508 Reported
Glaucoma Clinical sign HP:0000501 ~1/3 post-cataract surgery
High myopia Physical HP:0011003 Reported
Screwdriver-shaped incisors Physical HP:0006315 (abnormal dentition) Characteristic
Mulberry molars Physical HP:0006479-related Characteristic
Supernumerary maxillary incisors Physical HP:0011069 Characteristic
Diastema Physical HP:0000699 Reported
Long narrow face Physical HP:0000276 / HP:0000275 Craniofacial
Prominent nose Physical HP:0000448 Craniofacial
Large anteverted ears Physical HP:0000411 / HP:0000358 Craniofacial
Mandibular prognathism Physical HP:0000303 Craniofacial
Intellectual disability Behavioral/cognitive HP:0001249 ~30% of reported cases
Sensorineural hearing loss Clinical sign HP:0000407 Reported (esp. microdeletions)
Axial hypotonia Clinical sign HP:0008936 Reported (esp. microdeletions)
Limb/foot contractures Physical HP:0001371 Reported (esp. microdeletions)
Posterior Y-suture lens opacity (carriers) Clinical sign HP:0000519 (subtype) Characteristic female carrier sign

Supporting citations: male spectrum (PMID: 35122698): "congenital cataracts, vision loss, microcornea, nystagmus, microphthalmia, glaucoma, screwdriver blade-shaped incisors, supernumerary maxillary incisors, diastema, delays, intellectual disability, and dysmorphic facies." Craniofacial/dental features (PMID: 29042737): "facial dysmorphism such as long face, prominent nose and mandibular prognathism, ocular abnormalities such as congenital cataract, microcornea, microphthalmia and strabismus, and dental anomalies including mulberry molars and screwdriver-shaped incisors." Intellectual disability frequency (PMID: 25091991): "Mental retardation was present in about 30% of the reported cases."

Quality-of-life impact. The dominant QoL driver is bilateral congenital visual deprivation, which, without early surgery and amblyopia therapy, can cause lifelong low vision/blindness — a leading cause of preventable childhood blindness. Dental anomalies affect mastication, speech and self-image; intellectual disability (when present) affects education, independence and employment. Formal EQ-5D/SF-36 data specific to NHS are not available.

Section 4 — Genetic / Molecular Information

Causal gene. NHS (OMIM 302350) at Xp22.13, spanning ~650 kb of genomic DNA and encoding a 1,630-amino-acid putative nuclear/cytoplasmic protein with vertebrate orthologs and no homology to previously known genes at the time of discovery (PMID: 14564667): "identified protein-truncating mutations in a novel gene, which we have called 'NHS,' in five families. The NHS gene encompasses approximately 650 kb of genomic DNA, coding for a 1,630-amino acid putative nuclear protein."

Pathogenic variants. The typical molecular lesion is a protein-truncating variant causing premature termination (PMID: 30642278): "NHS mutations in the NHS-affected individuals typically result in premature truncation of the protein." Representative reported variants include:

Variant (cDNA) Protein Type Source
c.1735delA p.R579Gfs*91 Frameshift Chinese family
c.3333del p.Phe1111Leufs*9 Frameshift Reported
c.3916_3919del frameshift Frameshift Chinese family
c.2232delG p.Lys744AsnfsX15 Frameshift Carrier study
~0.92–1.83 Mb Xp22.13 deletions gene deletion Structural/CNV Contiguous-gene
  • Variant classification (ACMG/AMP): truncating variants are typically pathogenic (PVS1 + supporting criteria).
  • Variant type/class: predominantly frameshift, nonsense, small indels, splice, and whole/partial-gene microdeletions; rare structural rearrangements (translocations, duplication-triplication).
  • Allele frequency: essentially absent from population databases (gnomAD) — consistent with a severe, rare disorder.
  • Somatic vs germline: germline.
  • Functional consequence: loss of function / haploinsufficiency (no gain-of-function or dominant-negative mechanism established).

Allelic relationship and genotype–mechanism–severity correlation. NHS and isolated X-linked congenital cataract (CXN) are allelic (PMID: 19414485): "we show that NHS and X-linked cataract are allelic diseases" and "different mechanisms, aberrant transcription of the NHS gene or no functional NHS protein, lead to different diseases." Protein-truncating/deleting variants that abolish functional NHS protein cause the full syndrome, whereas copy-number rearrangements that alter NHS transcription (without abolishing protein) cause the milder isolated-cataract phenotype.

Modifier genes. No separate modifier gene is established; X-inactivation pattern is the principal modifier of female severity.

Epigenetic information. The key epigenetic determinant is X-chromosome inactivation; non-random/skewed XCI explains the variability among female carriers (PMID: 36370055). No disease-specific DNA-methylation or histone signature at the NHS locus has been reported.

Chromosomal abnormalities. Contiguous-gene microdeletions at Xp22.2–p22.13 cause NHS and can broaden the phenotype. A 1.83-Mb deletion encompassed NHS plus CTPS2, S100G, TXLNG, RBBP7, REPS2, SCML1, RAI2, SCML2 in a male with the classic tetrad plus sensorineural hearing loss, axial hypotonia and foot contractures (PMID: 35122698): "revealed a 1.83-Mb interstitial microdeletion at Xp22.2p22.13 (16,604,890-18,435,836) (GRCh37/hg19) that included NHS, CTPS2, S100G, TXLNG, RBBP7, REPS2, SCML1, RAI2, and SCML2." A ~0.92-Mb deletion spanning REPS2, NHS, SCML1, RAI2 was found in two brothers (PMID: 20882036). A balanced t(X;19)(p22.13;q13.1) translocation disrupting NHS produced classic NHS in a female.

Section 5 — Environmental Information

Environmental factors: none established. NHS is purely genetic. Lifestyle factors: not applicable. Infectious agents: not applicable — NHS is a congenital Mendelian disorder with no infectious etiology or trigger. (Note: congenital cataract as an isolated finding can have infectious causes such as congenital rubella, but these are differential diagnoses, not causes of NHS.)

Section 6 — Mechanism / Pathophysiology

Ordered causal chain

  1. A loss-of-function variant or deletion in NHS (Xp22.13) leads to absent or truncated NHS protein (hemizygous loss in males; haploinsufficiency in females). (Demonstrated.)
  2. Loss of the WAVE-homology-domain (WHD)-containing N-terminus of NHS-A/NHS-1A results in failure to engage the WAVE regulatory complex (WRC) (Abi, HSPC300, Nap1/NCKAP1, Sra1/CYFIP1). (Demonstrated in vitro.)
  3. Impaired WRC engagement leads to dysregulated actin remodelling — disruption of the circumferential actin ring, altered lamellipodia/focal adhesions, and abnormal cell spreading. (Demonstrated in cell models.)
  4. In the lens, loss of the cytoplasmic (exon-1) NHS isoform in elongating lens fiber cells results in defective fiber-cell differentiation/architecture → congenital cataract. (Demonstrated in Xcat mouse.)
  5. In parallel, loss of NHS's spatiotemporally regulated expression in the developing tooth, brain and craniofacial structures leads to the dental anomalies, facial dysmorphism and (in ~30%) intellectual disability. (Inferred from developmental expression pattern + phenotype co-segregation.)
  6. Branch (females): the severity of steps 4–5 is modulated by X-inactivation — favorable skewing attenuates, unfavorable skewing accentuates the phenotype. (Demonstrated epidemiologically.)
  7. Branch (CNV/transcriptional): rearrangements that alter NHS transcription without abolishing protein lead to the milder isolated X-linked cataract rather than full NHS. (Demonstrated.)

Detail

Molecular pathways. The central pathway is WRC-mediated Arp2/3-dependent actin polymerization (cytoskeletal signaling). NHS is a novel regulator of actin remodelling and cell morphology (PMID: 20332100): "NHS is a novel regulator of actin remodelling and cell morphology. NHS localizes to sites of cell-cell contact, the leading edge of lamellipodia and focal adhesions. The N-terminus of isoforms NHS-A and NHS-1A, implicated in the pathogenesis of NHS, have a functional WAVE homology domain that interacts with the Abi protein family, haematopoietic stem/progenitor cell protein 300 (HSPC300), Nap1 and Sra1." This mechanistically links NHS to the broader family of WRC-opathies (e.g., CYFIP2/NCKAP1 neurodevelopmental disorders).

Cellular processes. Cytoskeletal organization, cell–cell junction integrity, cell spreading/migration, and terminal differentiation of lens fiber cells. NHS knockdown disrupts the actin cytoskeleton and increases cell spreading; overexpression inhibits lamellipod formation (PMID: 20332100).

Protein dysfunction. Loss of function via truncation/deletion; the WHD is required for WRC binding. The functionally relevant isoform for cytoplasmic localization contains exon 1; isoforms lacking exon 1 mislocalize to the nucleus.

Molecular profiling / model evidence. In the Xcat mouse, wild-type Nhs is "strongly expressed within the cytoplasm of elongating lens fiber cells from wild-type neonate lens, but is significantly reduced within the Xcat lens" (PMID: 16357105). Developmental expression mapping shows "a complex pattern of temporally and spatially regulated expression, which, together with the pleiotropic features of NHS, suggests that this gene has key functions in the regulation of eye, tooth, brain, and craniofacial development" (PMID: 14564667).

Metabolic / immune / infectious involvement: none — NHS is a structural/cytoskeletal developmental disorder, not a metabolic, autoimmune, or infectious disease.

Suggested ontology terms

  • GO (biological process): actin cytoskeleton organization (GO:0030036); regulation of actin filament polymerization (GO:0030833); lamellipodium assembly (GO:0030032); lens fiber cell differentiation (GO:0070306); camera-type eye development (GO:0043010); odontogenesis (GO:0042476).
  • GO (cellular component): WAVE regulatory complex (GO:0031209); lamellipodium (GO:0030027); focal adhesion (GO:0005925); cell-cell adherens junction (GO:0005913); cytoplasm (GO:0005737).
  • CL (cell types): lens fiber cell (CL:0000181); lens epithelial cell (CL:0002224); odontoblast (CL:0000060); neuron (CL:0000540).

Section 7 — Anatomical Structures Affected

Organ level — primary: the eye/lens (UBERON:0000965 lens of camera-type eye; UBERON:0000970 eye). Secondary ocular structures: cornea (microcornea), whole globe (microphthalmia), optic pathway (visual deprivation), and secondary glaucoma. Teeth (UBERON:0001091) — dental anomalies. Craniofacial skeleton/face (UBERON:0001456 face; UBERON:0004765 skeletal element) — dysmorphism, mandibular prognathism. Brain (UBERON:0000955) — cognitive involvement in ~30%. Ear/auditory system — sensorineural hearing loss in some (notably microdeletions).

Body systems: visual/ophthalmic, dental/orofacial, nervous (CNS), and craniofacial/musculoskeletal; auditory in a subset.

Tissue/cell level: lens fiber cells and lens epithelial cells (cytoskeletal/differentiation defect); odontoblasts/dental epithelium; neurons (cognitive features). Relevant CL terms: lens fiber cell (CL:0000181), lens epithelial cell (CL:0002224), odontoblast (CL:0000060), neuron (CL:0000540).

Subcellular level: cytoplasm and the actin cytoskeleton / cell cortex; the WAVE regulatory complex (GO:0031209); lamellipodium (GO:0030027); focal adhesions (GO:0005925); cell-cell junctions (GO:0005913).

Localization / lateralization: cataracts are characteristically bilateral in affected males; female carrier opacities are typically bilateral and posterior Y-suture-centered.

Section 8 — Temporal Development

Onset. Congenital — cataracts and structural anomalies are present at or shortly after birth. Onset pattern is developmental/congenital, not acute.

Progression. The structural anomalies are largely stable/non-progressive, but there is a critical window for visual development: untreated bilateral congenital cataract causes deprivation amblyopia that becomes irreversible if not corrected early. Secondary complications (glaucoma, visual-axis opacification) can develop and progress after cataract surgery (glaucoma in ~1/3). A subset of patients show reported brain developmental changes (both prominent and regressive patterns have been described). Dental and craniofacial features become more apparent through childhood; systemic features such as dental anomalies and intellectual disability may take years to develop (PMID: 39858638), which contributes to under-diagnosis.

Duration / course. Chronic, lifelong. No spontaneous remission; the critical period for intervention is the first weeks of life (cataract surgery and amblyopia therapy).

Section 9 — Inheritance and Population

Inheritance. X-linked semidominant (X-linked dominant with milder female expression). Affected males transmit the variant to all daughters (obligate carriers) and no sons; carrier females transmit to 50% of offspring (affected sons; carrier/mildly affected daughters).

Penetrance / expressivity. Essentially complete penetrance in hemizygous males with variable expressivity; variable penetrance/expressivity in heterozygous females governed by skewed X-inactivation (PMID: 36370055). Female phenotype ranges from asymptomatic to posterior Y-suture opacities to — unusually — severe ocular phenotypes in some kindreds. Sex-specific expressivity: "In males, it causes bilateral dense pediatric cataracts, dental anomalies, and facial dysmorphisms. Females traditionally have a more subtle phenotype with discrete lens opacities as an isolated feature" (PMID: 39858638).

Genetic anticipation / mosaicism / founder effects: no anticipation (not a repeat-expansion disorder); no established germline mosaicism pattern; no reported founder effect — mutations are private and distributed across diverse populations.

Epidemiology. Ultra-rare; Orphanet lists prevalence < 1/1,000,000 (ORPHA:627). Precise incidence/prevalence are unestablished (PMID: 29042737): "This syndrome is very rare and the incidence of the disease has not been established so far."

Population demographics. Reports span Australian, North American, multiple Chinese, Taiwanese, Brazilian, Swiss, and Middle Eastern families — indicating worldwide distribution without geographic clustering or founder variant. Sex ratio: males fully affected, females milder; both sexes can carry/express. Age distribution: congenital onset; diagnosed from infancy onward.

Section 10 — Diagnostics

Clinical/ophthalmic examination. Slit-lamp biomicroscopy is central — it detects dense bilateral cataracts in males and posterior Y-suture opacities in carriers. Optical coherence tomography and standard pediatric ophthalmic workup (for microcornea, microphthalmia, nystagmus, strabismus, glaucoma) support the diagnosis. Dental examination documents screwdriver incisors, mulberry molars, supernumerary teeth, diastema.

Carrier sign. Posterior Y-suture-centered lens opacities with characteristic facial features are a sensitive and specific sign of carrier status (PMID: 22229851): "Lens opacities centered around the posterior Y-suture in the context of certain facial features were sensitive and specific clinical signs of carrier status for NHS mutation in asympt[omatic females]." Independently confirmed (PMID: 29402928): "One female carrier displayed lens opacities centered on the posterior Y-suture in both eyes, as well as mild dental abnormalities."

Genetic testing (confirmatory). Molecular diagnosis is the gold standard: - Single-gene NHS sequencing or targeted NGS gene panels for congenital/early-onset cataract — identify point/frameshift/nonsense variants. - Whole-exome sequencing (WES) — effective for novel variant discovery (used in multiple reported families). - Chromosomal microarray (CMA) / array-CGH — essential when sequencing is negative, to detect Xp22.13 microdeletions (PMID: 20882036, PMID: 35122698). - Karyotype + FISH — indicated in females with familial NHS and negative single-gene analysis, to detect balanced X-autosome translocations disrupting NHS.

Genetic testing of bilateral familial pediatric cataract reveals extraocular features and enables counseling (PMID: 39858638).

Clinical criteria / differential diagnosis. Diagnosis rests on the tetrad plus X-linked inheritance, confirmed molecularly. Differentials include isolated X-linked congenital cataract (CXN; allelic), other syndromic congenital cataracts (e.g., Lowe syndrome, cerebro-oculo-facio-skeletal conditions), and other causes of supernumerary teeth (cleidocranial dysplasia, familial adenomatous polyposis, Rubinstein-Taybi, Opitz G/BBB, oculofaciocardiodental, Robinow) (PMID: 30457727).

Screening. Cascade testing of at-risk relatives once the familial variant is known; slit-lamp screening of potential carrier females; newborn red-reflex examination.

Section 11 — Outcome / Prognosis

Survival/mortality. NHS is not a life-limiting disorder per se; life expectancy is essentially normal. No disease-specific mortality is established.

Morbidity and function. The principal morbidity is visual — bilateral congenital cataract risks lifelong low vision/blindness without timely surgery. Additional morbidity from secondary glaucoma (~1/3 of operated patients), visual-axis opacification, dental dysfunction, and, in ~30%, intellectual disability affecting education and independence.

Prognostic factors (visual). Better visual outcomes correlate with early surgery and absence of nystagmus/strabismus plus consistent amblyopia therapy (PMID: 35307324): "Better visual outcomes in operated eyes, however, are achieved in the setting of early presentation, bilateral infantile cataracts, absence of nystagmus or strabismus, and consistent amblyopia therapy."

Complications. Post-surgical visual-axis opacification, glaucoma, amblyopia; amenable to surveillance and timely management.

Section 12 — Treatment

There is no disease-modifying or gene-directed therapy for NHS. Management is entirely symptomatic/supportive:

  • Cataract surgery (primary intervention). Lens aspiration (vitrector) with posterior capsulotomy and anterior vitrectomy. Timing is critical: "cataract surgery is recommended at 6 weeks of age for unilateral cataract and between 6 and 8 weeks of age for bilateral cases" (PMID: 31317088). (NCIT: Cataract Surgery.)
  • Optical correction: aphakic contact lenses/glasses in infants; intraocular lens (IOL) in older children. Cochrane evidence finds no high-level superiority of IOL vs primary aphakia for bilateral infantile cataract (PMID: 36107778).
  • Amblyopia therapy: consistent occlusion/refractive therapy — a key determinant of visual outcome (PMID: 35307324).
  • Glaucoma management: monitoring and treatment of secondary glaucoma.
  • Dental/orthodontic care: management of supernumerary teeth, malocclusion, dental anomalies.
  • Developmental and educational support: for patients with intellectual disability; speech/occupational/physical therapy as needed. (NCIT: Rehabilitation Therapy.)
  • Audiology: hearing assessment and support where sensorineural hearing loss is present.
  • Genetic counseling: integral to management (see Section 13).

Pharmacotherapy / advanced therapeutics / experimental trials: no NHS-specific drugs, gene therapy, cell therapy, or RNA-based therapies are approved or in trials. No pharmacogenomic considerations are established.

Section 13 — Prevention

NHS cannot be prevented at the individual genetic level, but transmission risk can be managed:

  • Primary prevention / reproductive options: genetic counseling following X-linked recurrence rules; once the familial variant is identified, prenatal diagnosis and preimplantation genetic testing (PGT) become available. Genetic diagnosis "made possible accurate family counseling essential in all pediatric cataract cases" (PMID: 39858638).
  • Secondary prevention (early detection): newborn red-reflex screening and prompt referral for congenital cataract; cascade testing of at-risk relatives; slit-lamp screening of potential carrier females for Y-suture opacities.
  • Tertiary prevention: early cataract surgery + amblyopia therapy to prevent irreversible visual deprivation; glaucoma surveillance; dental and developmental support.
  • Counseling emphasis: because systemic features may take years to appear (PMID: 39858638), genetic testing of bilateral familial pediatric cataract is recommended to avoid misdiagnosis as isolated cataract.

Immunization, public-health/environmental interventions, and prophylactic medications are not applicable.

Section 14 — Other Species / Natural Disease

Taxonomy / orthologs. NHS orthologs are conserved across vertebrates (PMID: 14564667): "NHS orthologs were found in other vertebrates." The mouse ortholog is Nhs (Mus musculus, NCBI Taxon 10090). NHS defines a protein family with paralogs NHSL1 and NHSL2.

Natural disease in animals. No naturally occurring NHS-equivalent disease has been reported in companion animals or wildlife (no established OMIA natural model). The only robust animal model is the induced/mutant Xcat mouse (see Section 15).

Comparative biology. The WRC/actin-regulatory mechanism is evolutionarily conserved, supporting cross-species mechanistic relevance of rodent models.

Transmission: not applicable — non-communicable genetic disorder; no zoonotic potential.

Section 15 — Model Organisms

Primary model — Xcat mouse (mammalian, X-linked cataract). The Xcat mouse carries a large insertion between exons 1 and 2 of Nhs, inhibiting expression of the exon-1-containing (cytoplasmic) isoform and causing exclusive expression of the exon-1A isoform with reduced total Nhs transcript (PMID: 16357105). It recapitulates the cataract phenotype and demonstrates loss of cytoplasmic Nhs in elongating lens fiber cells, validating the lens-fiber-cell differentiation mechanism. A lacZ reporter-gene insertion mouse line was used to map developmental expression.

In vitro / cellular systems. Human lens epithelial cells (SRA 01/04) and mouse lens epithelial cells (αTN4) have been used to study NHS/junctional biology (PMID: 23288986): "a human lens epithelial cell line (SRA 01/04) and a mouse lens epithelial cell line (αTN4)." siRNA knockdown in cultured cells demonstrates actin-cytoskeleton disruption (PMID: 20332100).

Model characteristics / limitations. The Xcat mouse reproduces the ocular (cataract) phenotype well and dissects isoform-specific cytoplasmic targeting, but the dental, craniofacial and cognitive features are less completely modeled, and the mouse does not capture the full human tetrad. Genetically engineered knockout/conditional alleles would be needed to study extra-ocular developmental roles.

Resources: MGI (mouse Nhs); Cellosaurus (SRA 01/04, αTN4).

Mechanistic Model / Interpretation

 NHS loss-of-function variant / Xp22.13 deletion (germline, X-linked)
 |  (hemizygous in males; haploinsufficient in females)
 v
 Absent / truncated NHS protein  --> loss of N-terminal WAVE homology domain (WHD)
 |
 v
 Failure to engage WAVE Regulatory Complex (Abi, HSPC300, NCKAP1/Nap1, CYFIP1/Sra1)
 |
 v
 Dysregulated actin remodelling / cell morphology (lamellipodia, focal adhesions,
 cell-cell junctions, cortical actin ring)
|                          |                         |
v                          v                         v
 Lens fiber-cell            Tooth & craniofacial      Neuronal/brain
 differentiation defect     development disruption    development disruption
 (cytoplasmic isoform)              |                         |
v                          v                         v
 BILATERAL CONGENITAL       DENTAL ANOMALIES +         INTELLECTUAL
 CATARACT                   FACIAL DYSMORPHISM         DISABILITY (~30%)

 Female modifier branch:  X-inactivation skewing -> attenuates or accentuates severity
 Allelic branch:  transcription-altering CNV (protein preserved) -> isolated X-linked cataract

Upstream vs downstream. The mutation → loss of WHD → failed WRC binding → actin dysregulation axis is upstream and shared; the tissue-specific developmental failures (lens, tooth, face, brain) are downstream and account for pleiotropy. The X-inactivation and transcription-vs-protein branches explain, respectively, female variability and the NHS-vs-isolated-cataract dichotomy.

Evidence Base

PMID Title (abbrev.) Role
14564667 Mutations in a novel gene, NHS… Foundational gene identification; 1,630-aa protein; pleiotropic developmental expression
20332100 NHS encodes a functional WHD… Core mechanism — WRC binding, actin regulation
16357105 Xcat, a novel mouse model… Animal model; cytoplasmic isoform loss in lens fiber cells
19414485 X-linked cataract and NHS are allelic Genotype–mechanism–severity correlation
36370055 NHS pedigree, microdeletion, skewed XCI Haploinsufficiency + XCI female variability
41236159 Further delineation of male/female phenotypes Disease definition; gene location; female mildness
39858638 Genotype-phenotype in male/female carriers Sex-specific expressivity; diagnostic/counseling value
25091991 Novel mutation by WES ~30% intellectual disability frequency
35122698 Novel microdeletion… Male phenotype spectrum; 1.83-Mb contiguous-gene deletion
29042737 NHS: A Rare Case Report Craniofacial/dental features; incidence unestablished
20882036 Microdeletion at Xp22.13 (Taiwan) Second contiguous-gene deletion
22229851 Potential female carriers… Posterior Y-suture carrier sign (sensitive/specific)
29402928 Novel small deletion in NHS Independent confirmation of Y-suture carrier sign
35307324 Current management of infantile cataracts Visual prognostic factors; amblyopia therapy
31317088 Updates on management of pediatric cataract Cataract surgery timing
36107778 Cochrane: bilateral congenital cataract surgery Evidence on IOL vs aphakia
30642278 Novel truncation mutation by WES Truncating LoF as typical lesion
23288986 Lens epithelial cell lines In vitro cellular models
30457727 Genetic entities with supernumerary teeth Dental differential diagnosis

Mechanistic cross-support (WRC-opathies). Independent studies of CYFIP2 (PMID: 33149277, PMID: 30664714) show that disrupting WRC-mediated actin dynamics causes neurodevelopmental disorders — converging evidence that the NHS→WRC→actin axis is pathogenic, and contextualizing the intellectual-disability component of NHS within a broader "WRC-opathy" framework.

Limitations and Knowledge Gaps

  1. No primary dataset analysis. This report synthesizes published literature and ontology resources; no new patient-level or omics data were analyzed.
  2. Epidemiology unquantified. Precise incidence/prevalence are unestablished; only Orphanet's < 1/1,000,000 category and case-series counts exist.
  3. Mechanism of extra-ocular features partly inferred. The lens mechanism is well-demonstrated (Xcat); the causal chains to dental, craniofacial and cognitive phenotypes rest largely on developmental expression patterns and phenotype co-segregation rather than tissue-specific functional proof.
  4. Genotype–phenotype correlation incomplete. While mechanism (truncation vs transcriptional CNV) grades NHS vs isolated cataract, finer correlations (variant position vs severity, predictors of intellectual disability) are not firmly established. Some reports show atypically severe female phenotypes, challenging the "females always mild" generalization.
  5. No therapeutics pipeline. There are no disease-modifying therapies, trials, or validated biomarkers beyond the causal variant.
  6. Animal models incomplete. The Xcat mouse models cataract but not the full tetrad; dedicated knockout/conditional models of extra-ocular roles are lacking.

Proposed Follow-up Experiments / Actions

  1. Natural-history registry. Establish a multi-center NHS registry to quantify prevalence, penetrance/expressivity (especially female severity distribution), and long-term visual/cognitive outcomes.
  2. Genotype–phenotype meta-analysis. Aggregate all reported NHS variants (point mutations, indels, CNVs, translocations) with standardized HPO phenotyping to test variant-position/mechanism predictors of intellectual disability and female severity.
  3. X-inactivation studies. Systematically correlate XCI ratios (e.g., HUMARA/allele-specific methods) with phenotype severity in female carriers to validate skewing as the principal modifier.
  4. Tissue-specific functional models. Generate conditional Nhs knockouts (dental epithelium, neural crest, neurons) and NHS-deficient iPSC-derived organoids (lens, neuronal, craniofacial) to directly test downstream causal steps.
  5. WRC-interaction mapping. Quantify how specific NHS truncations disrupt WRC binding (Abi/HSPC300/NCKAP1/CYFIP1) and actin dynamics, linking molecular defect to cellular phenotype gradient.
  6. Diagnostic optimization. Validate a tiered pediatric-cataract testing algorithm (NGS panel → WES → CMA → karyotype/FISH) to minimize under-diagnosis of NHS presenting as "isolated" cataract.

Report compiled from 13 confirmed findings and 35 reviewed papers over a 5-iteration autonomous investigation. Evidence types: human clinical (cohorts, case reports, carrier studies), model organism (Xcat mouse), in vitro (lens epithelial cell lines, siRNA knockdown), and ontology/database resources (OMIM, Orphanet, HPO, MONDO).

Artifacts

Reference Validation

Checked with linkml-reference-validator 0.3.0.

Outcome Count
References checked 21
Resolved 21
Unresolved (possible confabulation) 0
Unverifiable 0
References weighed for topical relevance 21
On topic 17
Off topic 0

All extracted references resolved successfully.

Term Validation

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

Outcome Count
Terms checked 45
Resolved 42
Unresolved (possible confabulation) 0
Obsolete 2
Unverifiable 1
Terms whose name was checked 23
Terms named correctly 3
Terms named as a different term 18
Terms whose name is worth a second look 2

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:0010545 (3 mentions) - the report calls it "MONDO"; MONDO calls it Nance-Horan syndrome
  • HP:0000519 (2 mentions) - the report calls it "congenital cataract", "subtype"; HP calls it Developmental cataract
  • HP:0000482 (1 mention) - the report calls it "Physical"; HP calls it Microcornea
  • HP:0000568 (1 mention) - the report calls it "Physical"; HP calls it Microphthalmia
  • HP:0000639 (1 mention) - the report calls it "Clinical sign"; HP calls it Nystagmus
  • HP:0000486 (1 mention) - the report calls it "Clinical sign"; HP calls it Strabismus
  • HP:0000508 (1 mention) - the report calls it "Physical"; HP calls it Ptosis
  • HP:0000501 (1 mention) - the report calls it "Clinical sign"; HP calls it Glaucoma
  • HP:0011003 (1 mention) - the report calls it "Physical"; HP calls it High myopia
  • HP:0006315 (1 mention) - the report calls it "abnormal dentition"; HP calls it Solitary median maxillary central incisor
  • HP:0011069 (1 mention) - the report calls it "Physical"; HP calls it Supernumerary tooth
  • HP:0000699 (1 mention) - the report calls it "Physical"; HP calls it Diastema
  • HP:0000448 (1 mention) - the report calls it "Physical"; HP calls it Prominent nose
  • HP:0000303 (1 mention) - the report calls it "Physical"; HP calls it Mandibular prognathia
  • HP:0001249 (1 mention) - the report calls it "Behavioral/cognitive"; HP calls it Intellectual disability
  • HP:0000407 (1 mention) - the report calls it "Clinical sign"; HP calls it Sensorineural hearing impairment
  • HP:0008936 (1 mention) - the report calls it "Clinical sign"; HP calls it Axial hypotonia
  • HP:0001371 (1 mention) - the report calls it "Physical"; HP calls it Flexion contracture

Obsolete terms

These terms are real but deprecated. Citing one is not a fabrication; it does mean the report is naming something the ontology has retired:

  • GO:0005913 (GO_0005913) (2 mentions) - replaced by GO:0005912
  • CL:0000181 (obsolete metabolising cell) (2 mentions)

Terms whose name is worth a second look

The report's name for these is recognisably related to the term's own name without being one of them. A loose paraphrase reads the same way as a citation of the wrong sibling term - and so does a related synonym, which the ontology records precisely because it names something adjacent rather than the same thing - so these are listed rather than judged:

  • GO:0031209 (2 mentions) - the report calls it "WAVE regulatory complex"; GO calls it SCAR complex, and lists "WAVE regulatory complex" among its other names
  • UBERON:0001091 (1 mention) - the report calls it "Teeth"; UBERON calls it calcareous tooth, and lists "tooth" among its other names

Terms named inconsistently

The report gives these identifiers more than one name of its own:

  • HP:0000519 - called "congenital cataract", "subtype"

Prefixes with no resolver

Terms carrying these prefixes were not checked either way, because no configured ontology covers them. An unrecognised prefix may name an ontology this run could not reach as easily as one that does not exist, so nothing here is evidence of fabrication: ORPHA.