Zimmermann-Laband Syndrome

Mendelian MONDO:0000200 Pathograph 26 Show in embeddings browser hereditary disease multiple congenital anomalies syndrome syndromic neurodevelopmental disorder potassium channelopathy

Zimmermann-Laband syndrome is a rare multiple congenital anomalies and neurodevelopmental disorder characterized by gingival fibromatosis, coarse facial appearance, hypertrichosis, intellectual disability, and hypoplastic or absent nails or terminal phalanges. It is genetically heterogeneous, with pathogenic variants in KCNH1, KCNN3, and ATP6V1B2 reported in affected individuals.

Ask OpenScientist

Ask a research question about Zimmermann-Laband Syndrome. OpenScientist will conduct autonomous deep research using the Disorder Mechanisms Knowledge Base and PubMed literature (typically 10-30 minutes).

Submitting...

Do not include personal health information in your question. Questions and results are cached in your browser's local storage.

4
Mappings
1
Inheritance
10
Pathophys.
48
Phenotypes
1
Hypotheses
26
Pathograph
3
Genes
1
Variants
2
Medical Actions
3
Subtypes
4
Differentials
12
References
1
Deep Research
🔗

Mappings

MONDO
MONDO:0000200 Zimmermann-Laband syndrome
skos:exactMatch MONDO
MONDO:0024526 Zimmermann-Laband syndrome 1 Not Yet Curated
skos:narrowMatch MONDO
MONDO:0024526 (OMIM:135500) is_a the MONDO:0000200 anchor of this entry and is defined as its KCNH1 subtype (intersection_of RO:0004003 HGNC:6250; also is_a MONDO:0100485 KCNH1 associated disorder). This entry curates KCNH1 gain-of-function variants alongside the KCNN3 and ATP6V1B2 aetiologies, so the KCNH1 child term is covered here. narrowMatch rather than exactMatch because the anchor also subsumes the non-KCNH1 forms.
MONDO:0014646 Zimmermann-Laband syndrome 2 Not Yet Curated
skos:narrowMatch MONDO
ATP6V1B2-related molecular subtype of this umbrella entry.
MONDO:0032854 Zimmermann-Laband syndrome 3 Not Yet Curated
skos:narrowMatch MONDO
KCNN3-related molecular subtype of this umbrella entry.
👪

Inheritance

1
Autosomal dominant inheritance HP:0000006
Most molecularly solved cases are sporadic or de novo dominant potassium channelopathy cases, although older literature and Orphanet note familial aggregation and autosomal-recessive hypotheses.
Autosomal dominant inheritance
Show evidence (3 references)
PMID:23994350 SUPPORT Human Clinical
"An autosomal dominant mutation with high mutation rate and rare instances of germinal mosaicism seems the most likely inheritance pattern."
Literature review of sporadic and familial cases supports autosomal dominant inheritance with possible germline mosaicism.
PMID:31155282 SUPPORT Human Clinical
"We report de novo missense variants in KCNN3 in three individuals with typical clinical features of ZLS."
De novo KCNN3 variants in typical ZLS cases support dominant inheritance for a molecular subtype.
ORPHA:3473 REFUTE Other
"## Inheritance - Autosomal recessive ## Natural history"
Orphanet retains an autosomal-recessive assertion from the pre-molecular literature; this conflicts with the de novo dominant molecular evidence and is retained to make the disagreement explicit.
◆

Subtypes

3
Zimmermann-Laband syndrome type 1 (KCNH1-related) MONDO:0024526
KCNH1 hgnc:6250 HUGO Gene Nomenclature Committee (hgnc) Relation: this subtype is caused by variation in this gene This subtype is caused by variation in KCNH1 (hgnc:6250). hgnc:6250 is a gene from the HUGO Gene Nomenclature Committee.
KCNH1-related ZLS is caused by heterozygous gain-of-function missense variants in the Kv10.1 voltage-gated potassium channel.
Show evidence (2 references)
PMID:25915598 SUPPORT Human Clinical
"We report that heterozygous missense mutations in KCNH1 account for a considerable proportion of ZLS."
Establishes the KCNH1-related molecular subtype.
PMID:25915598 SUPPORT In Vitro
"These data support a gain-of-function effect for all ZLS-associated KCNH1 mutants."
Functional studies support the gain-of-function wording for the KCNH1-related subtype.
Zimmermann-Laband syndrome type 2 (ATP6V1B2-related) MONDO:0014646
ATP6V1B2 hgnc:854 HUGO Gene Nomenclature Committee (hgnc) Relation: this subtype is caused by variation in this gene This subtype is caused by variation in ATP6V1B2 (hgnc:854). hgnc:854 is a gene from the HUGO Gene Nomenclature Committee.
ATP6V1B2-related ZLS is caused by de novo monoallelic variants affecting the B2 subunit of the vacuolar proton ATPase. Functional studies of p.Arg485Pro and other tested dominant ATP6V1B2 substitutions support increased V-ATPase activity, while clinical expression spans a ZLS-DDOD-DOORS continuum.
Show evidence (3 references)
PMID:25915598 SUPPORT Human Clinical
"We also identified a recurrent de novo missense change in ATP6V1B2, encoding the B2 subunit of the multimeric vacuolar H(+) ATPase, in two individuals with ZLS."
Establishes the ATP6V1B2-related molecular subtype.
PMID:39210597 SUPPORT In Vitro
"We investigated the functional consequences of the identified ATP6V1B2 and ATP6V1C1 variants, together with the p.Arg485Pro change in ATP6V1B2"
Establishes that p.Arg485Pro was included in the functional series.
PMID:39210597 SUPPORT In Vitro
"We observed a significant higher acidity of lysosomes in all patients’ cell lines compared with control cells, indicating a hyperactive behavior of the proton pumps assembling the mutant B2/C1 subunits."
The p.Arg485Pro line was among the tested patient lines showing hyperactive proton pumping and lysosomal hyperacidification.
Zimmermann-Laband syndrome type 3 (KCNN3-related) MONDO:0032854
KCNN3 hgnc:6292 HUGO Gene Nomenclature Committee (hgnc) Relation: this subtype is caused by variation in this gene This subtype is caused by variation in KCNN3 (hgnc:6292). hgnc:6292 is a gene from the HUGO Gene Nomenclature Committee.
KCNN3-related ZLS is caused by de novo gain-of-function missense variants in the SK3 calcium-activated potassium channel.
Show evidence (2 references)
PMID:31155282 SUPPORT Human Clinical
"We report de novo missense variants in KCNN3 in three individuals with typical clinical features of ZLS."
Establishes the KCNN3-related molecular subtype.
PMID:31155282 SUPPORT In Vitro
"Patch-clamp whole-cell recordings of KCNN3 channel-expressing CHO cells demonstrated that disease-associated mutations result in gain of function of the mutant channels, characterized by increased Ca2+ sensitivity leading to faster and more complete activation of KCNN3 mutant channels."
Functional studies support the gain-of-function wording for the KCNN3-related subtype.
◈

Mechanistic Hypotheses

1
Ciliary Kv10.1 and Hedgehog signaling explain extraneurological ZLS1 features
ciliary_hedgehog_extraneurological EMERGING
Evidence balance 1 support
Proposes that KCNH1-related gingival, nail, and distal digital anomalies arise from a non-excitable-cell role of Kv10.1 at the primary cilium. The cellular phenotype is demonstrated in fibroblast and RPE cultures, but the link to specific developing human tissues has not been shown.
Pathograph links
Increased potassium-channel conductance -> KCNH1-related ciliary signaling disruption INDIRECT UNKNOWN INTERMEDIATES
KCNH1-related ciliary signaling disruption -> Gingival and dental developmental overgrowth INDIRECT UNKNOWN INTERMEDIATES
KCNH1-related ciliary signaling disruption -> Distal digital and nail developmental abnormality INDIRECT UNKNOWN INTERMEDIATES
Show evidence (1 reference)
PMID:35639255 SUPPORT In Vitro
"the pathogenic missense variants (L352V and R330Q; NP_002229.1) perturb cilia morphology, assembly/disassembly, and Sonic Hedgehog signaling, disclosing a multifaceted role of the protein"
Provides the in-vitro basis for the emerging ciliary/Hedgehog model.
⚙

Pathophysiology

10
Increased potassium-channel conductance
ZLS-associated KCNH1 and KCNN3 missense variants increase potassium-channel activity or conductance, defining a syndromic neurodevelopmental potassium-channelopathy mechanism for ZLS1 and ZLS3.
Ciliary Kv10.1 and Hedgehog signaling explain extraneurological ZLS1 features
KCNH1 hgnc:6250 HUGO Gene Nomenclature Committee (hgnc) Relation: this pathophysiological event involves this gene This pathophysiological event involves KCNH1 (hgnc:6250). hgnc:6250 is a gene from the HUGO Gene Nomenclature Committee. KCNN3 hgnc:6292 HUGO Gene Nomenclature Committee (hgnc) Relation: this pathophysiological event involves this gene This pathophysiological event involves KCNN3 (hgnc:6292). hgnc:6292 is a gene from the HUGO Gene Nomenclature Committee.
potassium ion transmembrane transport GO:0071805 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased potassium ion transmembrane transport (GO:0071805). GO:0071805 is a biological process from the Gene Ontology. ↑ INCREASED
voltage-gated potassium channel activity GO:0005249 Gene Ontology (GO) Relation: this pathophysiological event involves this molecular function This pathophysiological event involves increased voltage-gated potassium channel activity (GO:0005249). GO:0005249 is a molecular function from the Gene Ontology. ↑ INCREASED calcium-activated potassium channel activity GO:0015269 Gene Ontology (GO) Relation: this pathophysiological event involves this molecular function This pathophysiological event involves increased calcium-activated potassium channel activity (GO:0015269). GO:0015269 is a molecular function from the Gene Ontology. ↑ INCREASED
Downstream
KCNH1-related ciliary signaling disruption Ciliary Kv10.1 and Hedgehog signaling explain extraneurological ZLS1 features
Neurodevelopmental dysfunction
Gingival and dental developmental overgrowth
Distal digital and nail developmental abnormality
Coarse facial features
Generalized hypertrichosis
Show evidence (3 references)
PMID:25915598 SUPPORT In Vitro
"These data support a gain-of-function effect for all ZLS-associated KCNH1 mutants."
Patch-clamp data support increased KCNH1 function.
PMID:31155282 SUPPORT In Vitro
"Patch-clamp whole-cell recordings of KCNN3 channel-expressing CHO cells demonstrated that disease-associated mutations result in gain of function of the mutant channels, characterized by increased Ca2+ sensitivity leading to faster and more complete activation of KCNN3 mutant channels."
CHO-cell patch-clamp data support increased KCNN3 function.
PMID:33594261 SUPPORT Human Clinical
"We suggest to combine the phenotypes and define a new subgroup of potassium channelopathies caused by increased K+ conductance, referred to as syndromic neurodevelopmental K+ channelopathies due to dominant variants in KCNH1, KCNK4, or KCNN3."
Places KCNH1- and KCNN3-related ZLS in a gain-of-conductance group.
ATP6V1B2 p.Arg485Pro hyperactive V-ATPase
The recurrent de novo ATP6V1B2 p.Arg485Pro ZLS2 substitution produces a hyperactive vacuolar H+ ATPase state in patient-derived fibroblasts, with increased proton-pumping activity and lysosomal acidification. This experimentally demonstrated gain of function supersedes the earlier computational complex-assembly prediction as the proximal mechanism.
dermal fibroblast CL:0002551 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves dermal fibroblast, annotated with fibroblast of dermis (CL:0002551). CL:0002551 is a cell type from the Cell Ontology.
ATP6V1B2 hgnc:854 HUGO Gene Nomenclature Committee (hgnc) Relation: this pathophysiological event involves this gene This pathophysiological event involves ATP6V1B2 (hgnc:854). hgnc:854 is a gene from the HUGO Gene Nomenclature Committee.
Genetic context ATP6V1B2 hgnc:854 HUGO Gene Nomenclature Committee (hgnc) Relation: this genetic context concerns this gene This genetic context concerns ATP6V1B2 (hgnc:854). hgnc:854 is a gene from the HUGO Gene Nomenclature Committee. allele_type: missense variant_origin: DE_NOVO zygosity: HETEROZYGOUS functional_impact_category: GAIN_OF_FUNCTION
The recurrent ZLS2 allele p.Arg485Pro was tested in primary patient fibroblasts and is included among the dominant ATP6V1B2 substitutions that increased V-ATPase proton-pump activity.
vacuolar acidification GO:0007035 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased vacuolar acidification (GO:0007035). GO:0007035 is a biological process from the Gene Ontology. ↑ INCREASED
proton transmembrane transporter activity GO:0015078 Gene Ontology (GO) Relation: this pathophysiological event involves this molecular function This pathophysiological event involves increased proton transmembrane transporter activity (GO:0015078). GO:0015078 is a molecular function from the Gene Ontology. ↑ INCREASED
Downstream
Abnormal lysosomal morphology
Lysosomal substrate accumulation
Impaired autophagic flux
ATP6V1B2-related altered ciliogenesis
Neurodevelopmental dysfunction
Distal digital and nail developmental abnormality
Show evidence (2 references)
PMID:39210597 SUPPORT In Vitro
"We investigated the functional consequences of the identified ATP6V1B2 and ATP6V1C1 variants, together with the p.Arg485Pro change in ATP6V1B2"
Establishes that p.Arg485Pro was included in the functional series.
PMID:39210597 SUPPORT In Vitro
"We observed a significant higher acidity of lysosomes in all patients’ cell lines compared with control cells, indicating a hyperactive behavior of the proton pumps assembling the mutant B2/C1 subunits."
The tested patient lines, including the p.Arg485Pro fibroblasts, showed hyperactive proton pumping and lysosomal hyperacidification.
Abnormal lysosomal morphology
Primary fibroblasts carrying ATP6V1B2 p.Arg485Pro showed increased numbers and size of lysosomes and aberrant vesicular ultrastructure.
dermal fibroblast CL:0002551 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves dermal fibroblast, annotated with fibroblast of dermis (CL:0002551). CL:0002551 is a cell type from the Cell Ontology.
lysosome GO:0005764 Gene Ontology (GO) Relation: this pathophysiological event involves this cellular component This pathophysiological event involves lysosome (GO:0005764). GO:0005764 is a cellular component from the Gene Ontology.
Show evidence (3 references)
PMID:39210597 SUPPORT In Vitro
"Consistently, similar levels of endogenous ATP6V1B2 were also found in primary fibroblasts obtained from affected (B2A332V, B2Q376K, and B2R485P) and control individuals (Figure S3)."
Establishes that the primary-fibroblast series included p.Arg485Pro.
PMID:39210597 SUPPORT In Vitro
"Notably, a marked increase in the size and number of lysosomes in cells endogenously expressing each of the tested B2 and C1 mutants was observed by immunofluorescence analysis and western blot analyses (Figures 2C and 2D), as observed in lysosomal storage disorders."
All tested lines, including p.Arg485Pro fibroblasts, showed increased lysosome size and number.
PMID:39210597 SUPPORT In Vitro
"In particular, in fibroblasts expressing B2A322V and B2R485P many of these vesicles seemed to be partially fused (Figures 5E and 5F) or in close proximity to each other (Figures 5I–5L)."
Directly identifies abnormal vesicular ultrastructure in p.Arg485Pro fibroblasts.
Lysosomal substrate accumulation
Patient-derived ATP6V1B2 p.Arg485Pro fibroblasts accumulated lysosomal substrates, consistent with a cellular storage phenotype despite increased acidification.
dermal fibroblast CL:0002551 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves dermal fibroblast, annotated with fibroblast of dermis (CL:0002551). CL:0002551 is a cell type from the Cell Ontology.
lysosome GO:0005764 Gene Ontology (GO) Relation: this pathophysiological event involves this cellular component This pathophysiological event involves lysosome (GO:0005764). GO:0005764 is a cellular component from the Gene Ontology.
Show evidence (2 references)
PMID:39210597 SUPPORT In Vitro
"Consistently, similar levels of endogenous ATP6V1B2 were also found in primary fibroblasts obtained from affected (B2A332V, B2Q376K, and B2R485P) and control individuals (Figure S3)."
Establishes that the tested primary-fibroblast series included p.Arg485Pro.
PMID:39210597 SUPPORT In Vitro
"Analyses performed using specific probes (i.e., BTR ceramide and Filipin) showed a significantly increased storage of both substrates in all tested patients’ cell lines compared with controls cells (Figures 3A-3D), suggesting a generalized defective hydrolytic activity of lysosomal enzymes..."
All tested patient lines, including the p.Arg485Pro fibroblasts, accumulated cholesterol and ceramide.
Impaired autophagic flux
ATP6V1B2 p.Arg485Pro patient fibroblasts showed autophagosome accumulation and defective autophagic flux.
dermal fibroblast CL:0002551 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves dermal fibroblast, annotated with fibroblast of dermis (CL:0002551). CL:0002551 is a cell type from the Cell Ontology.
autophagic process GO:0006914 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves decreased autophagic process, annotated with autophagy (GO:0006914). GO:0006914 is a biological process from the Gene Ontology. ↓ DECREASED
Show evidence (2 references)
PMID:39210597 SUPPORT In Vitro
"Consistently, similar levels of endogenous ATP6V1B2 were also found in primary fibroblasts obtained from affected (B2A332V, B2Q376K, and B2R485P) and control individuals (Figure S3)."
Establishes that the tested primary-fibroblast series included p.Arg485Pro.
PMID:39210597 SUPPORT In Vitro
"Immunofluorescence and western blot analysis using an anti LC3I/II antibody as probe showed a significant accumulation of autophagosomes at steady state condition as well as after autophagy flux induction with EBSS in all tested patients’ fibroblasts compared with control cells (Figures 6A-6C,..."
All tested patient fibroblasts, including the p.Arg485Pro line, accumulated autophagosomes during the impaired flux.
Neurodevelopmental dysfunction
Molecularly heterogeneous ZLS converges on developmental delay or intellectual disability and variable seizure susceptibility.
central nervous system UBERON:0001017 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in central nervous system (UBERON:0001017). UBERON:0001017 is an anatomical location from the Uberon multi-species anatomy ontology.
Downstream
Global developmental delay
Intellectual disability
Seizure
Show evidence (2 references)
PMID:33594261 SUPPORT Human Clinical
"There is notable overlap in the phenotypic findings of these syndromes associated with dominant KCNN3, KCNH1, and KCNK4 variants, sharing developmental delay and/or ID, coarse facial features, gingival enlargement, distal digital hypoplasia, and hypertrichosis."
Supports developmental delay/ID in the potassium-channel subtypes.
PMID:23994350 SUPPORT Human Clinical
"Tabulation of clinical features confirmed the core phenotype and identified developmental delay as the unique major clinical problem (occurring in 40% of the cases) with a moderately high risk of epilepsy (13%)."
Quantifies developmental delay and epilepsy across historical ZLS cases.
Gingival and dental developmental overgrowth
Gingival fibromatosis can cover tooth crowns and delay eruption, producing functional and aesthetic complications.
gingiva UBERON:0001828 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in gingiva (UBERON:0001828). UBERON:0001828 is an anatomical location from the Uberon multi-species anatomy ontology.
Downstream
Gingival fibromatosis
Delayed eruption of teeth
Show evidence (1 reference)
PMID:40604848 SUPPORT Human Clinical
"A common manifestation of these syndromes is gingival fibromatosis, which may partially or completely cover tooth crowns, leading in some cases to functional and aesthetic problems, as well as delayed tooth eruption."
Links gingival fibromatosis to tooth coverage and delayed eruption.
Distal digital and nail developmental abnormality
Hypoplasia or aplasia of nails and terminal phalanges is a core distal developmental feature of ZLS.
fingernail UBERON:0009565 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in fingernail, annotated with nail of manual digit (UBERON:0009565). UBERON:0009565 is an anatomical location from the Uberon multi-species anatomy ontology.
Downstream
Hypoplastic fingernail
Absent fingernail
Aplasia of distal finger phalanx
Short distal phalanx of finger
Show evidence (1 reference)
PMID:25915598 SUPPORT Human Clinical
"Zimmermann-Laband syndrome (ZLS) is a developmental disorder characterized by facial dysmorphism with gingival enlargement, intellectual disability, hypoplasia or aplasia of nails and terminal phalanges, and hypertrichosis."
Identifies nail and terminal-phalanx abnormalities as core features.
⬡

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Zimmermann-Laband 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.
●

Phenotypes

48
Cardiovascular 1
Splenomegaly OCCASIONAL HP:0001744 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is splenomegaly (HP:0001744). HP:0001744 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0001744 | Splenomegaly | Occasional (29-5%)"
Orphanet records splenomegaly as occasional.
Digestive 1
Hepatomegaly OCCASIONAL HP:0002240 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is hepatomegaly (HP:0002240). HP:0002240 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0002240 | Hepatomegaly | Occasional (29-5%)"
Orphanet records hepatomegaly as occasional.
Ear 1
Sensorineural hearing impairment VERY_RARE HP:0000407 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is sensorineural hearing impairment (HP:0000407). HP:0000407 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0000407 | Sensorineural hearing impairment | Very rare (<4-1%)"
Orphanet records sensorineural hearing impairment as very rare.
Eye 2
Hypertelorism OCCASIONAL HP:0000316 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is hypertelorism (HP:0000316). HP:0000316 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0000316 | Hypertelorism | Occasional (29-5%)"
Orphanet records hypertelorism as occasional.
Cataract OCCASIONAL HP:0000518 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is cataract (HP:0000518). HP:0000518 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0000518 | Cataract | Occasional (29-5%)"
Orphanet records cataract as occasional.
Head and Neck 13
Wide mouth FREQUENT HP:0000154 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is wide mouth (HP:0000154). HP:0000154 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0000154 | Wide mouth | Frequent (79-30%)"
Orphanet records wide mouth as frequent.
Bulbous nose FREQUENT 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)
ORPHA:3473 SUPPORT Other
"HP:0000414 | Bulbous nose | Frequent (79-30%)"
Orphanet records bulbous nose as frequent.
Coarse facial features HP:0000280 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is coarse facial features (HP:0000280). HP:0000280 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:33594261 SUPPORT Human Clinical
"There is notable overlap in the phenotypic findings of these syndromes associated with dominant KCNN3, KCNH1, and KCNK4 variants, sharing developmental delay and/or ID, coarse facial features, gingival enlargement, distal digital hypoplasia, and hypertrichosis."
Identifies coarse facial features as part of the overlapping syndromic potassium-channelopathy phenotype.
Macroglossia OCCASIONAL HP:0000158 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is macroglossia (HP:0000158). HP:0000158 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0000158 | Macroglossia | Occasional (29-5%)"
Orphanet records macroglossia as occasional.
Cleft palate OCCASIONAL HP:0000175 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is cleft palate (HP:0000175). HP:0000175 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0000175 | Cleft palate | Occasional (29-5%)"
Orphanet records cleft palate as occasional.
Bifid uvula OCCASIONAL HP:0000193 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is bifid uvula (HP:0000193). HP:0000193 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0000193 | Bifid uvula | Occasional (29-5%)"
Orphanet records bifid uvula as occasional.
High palate OCCASIONAL HP:0000218 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is high palate (HP:0000218). HP:0000218 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0000218 | High palate | Occasional (29-5%)"
Orphanet records high palate as occasional.
Micrognathia OCCASIONAL HP:0000347 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is micrognathia (HP:0000347). HP:0000347 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0000347 | Micrognathia | Occasional (29-5%)"
Orphanet records micrognathia as occasional.
Short neck OCCASIONAL HP:0000470 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is short neck (HP:0000470). HP:0000470 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0000470 | Short neck | Occasional (29-5%)"
Orphanet records short neck as occasional.
Downslanted palpebral fissures OCCASIONAL HP:0000494 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is downslanted palpebral fissures (HP:0000494). HP:0000494 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0000494 | Downslanted palpebral fissures | Occasional (29-5%)"
Orphanet records downslanted palpebral fissures as occasional.
Hypodontia OCCASIONAL HP:0000668 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is hypodontia (HP:0000668). HP:0000668 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0000668 | Hypodontia | Occasional (29-5%)"
Orphanet records hypodontia as occasional.
Supernumerary tooth OCCASIONAL HP:0011069 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is supernumerary tooth (HP:0011069). HP:0011069 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0011069 | Supernumerary tooth | Occasional (29-5%)"
Orphanet records supernumerary tooth as occasional.
Delayed eruption of teeth OCCASIONAL HP:0000684 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is delayed eruption of teeth (HP:0000684). HP:0000684 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:40604848 SUPPORT Human Clinical
"A common manifestation of these syndromes is gingival fibromatosis, which may partially or completely cover tooth crowns, leading in some cases to functional and aesthetic problems, as well as delayed tooth eruption."
The case report and protocol supports delayed tooth eruption as a complication of gingival fibromatosis.
Limbs 2
Pes cavus OCCASIONAL HP:0001761 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is pes cavus (HP:0001761). HP:0001761 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0001761 | Pes cavus | Occasional (29-5%)"
Orphanet records pes cavus as occasional.
Pes planus OCCASIONAL HP:0001763 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is pes planus (HP:0001763). HP:0001763 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0001763 | Pes planus | Occasional (29-5%)"
Orphanet records pes planus as occasional.
Musculoskeletal 2
Joint hypermobility FREQUENT HP:0001382 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is joint hypermobility (HP:0001382). HP:0001382 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0001382 | Joint hypermobility | Frequent (79-30%)"
Orphanet records joint hypermobility as frequent.
Floppy infant OCCASIONAL HP:0008947 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is floppy infant (HP:0008947). HP:0008947 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0008947 | Floppy infant | Occasional (29-5%)"
Orphanet records floppy infant as occasional.
Nervous System 3
Global developmental delay FREQUENT HP:0001263 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is global developmental delay (HP:0001263). HP:0001263 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:23994350 SUPPORT Human Clinical
"Tabulation of clinical features confirmed the core phenotype and identified developmental delay as the unique major clinical problem (occurring in 40% of the cases) with a moderately high risk of epilepsy (13%)."
Directly reports developmental delay in 40% of reviewed ZLS cases, supporting the FREQUENT band and the HPO term whose exact synonym includes developmental delay.
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 (2 references)
ORPHA:3473 SUPPORT Other
"HP:0001249 | Intellectual disability | Frequent (79-30%)"
Orphanet records intellectual disability as frequent.
PMID:33594261 SUPPORT Human Clinical
"There is notable overlap in the phenotypic findings of these syndromes associated with dominant KCNN3, KCNH1, and KCNK4 variants, sharing developmental delay and/or ID, coarse facial features, gingival enlargement, distal digital hypoplasia, and hypertrichosis."
Directly names intellectual disability in the overlapping potassium-channel subtype phenotype; the FREQUENT band is independently supported by Orphanet.
Seizure OCCASIONAL HP:0001250 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is seizure (HP:0001250). HP:0001250 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
ORPHA:3473 SUPPORT Other
"HP:0001250 | Seizure | Occasional (29-5%)"
Orphanet records seizure as occasional.
PMID:23994350 SUPPORT Human Clinical
"Tabulation of clinical features confirmed the core phenotype and identified developmental delay as the unique major clinical problem (occurring in 40% of the cases) with a moderately high risk of epilepsy (13%)."
Literature review reports epilepsy in 13% of reviewed cases, consistent with occasional frequency.
Growth 1
Growth delay OCCASIONAL HP:0001510 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is growth delay (HP:0001510). HP:0001510 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0001510 | Growth delay | Occasional (29-5%)"
Orphanet records growth delay as occasional.
Other 22
Gingival fibromatosis VERY_FREQUENT HP:0000169 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is gingival fibromatosis (HP:0000169). HP:0000169 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
ORPHA:3473 SUPPORT Other
"HP:0000169 | Gingival fibromatosis | Obligate (100%)"
Orphanet supports the historical hallmark association, but its obligate frequency is not retained because later molecular cases lack the feature.
PMID:34907639 SUPPORT Human Clinical
"Gingival overgrowth is absent in both individuals."
Demonstrates that gingival overgrowth is not obligate in KCNN3-related ZLS.
Wide nose FREQUENT HP:0000445 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is wide nose (HP:0000445). HP:0000445 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0000445 | Wide nose | Frequent (79-30%)"
Orphanet records wide nose as frequent.
Hypoplastic fingernail FREQUENT HP:0001804 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is hypoplastic fingernail (HP:0001804). HP:0001804 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0001804 | Hypoplastic fingernail | Frequent (79-30%)"
Orphanet records hypoplastic fingernail as frequent.
Absent fingernail FREQUENT HP:0001817 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is absent fingernail (HP:0001817). HP:0001817 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0001817 | Absent fingernail | Frequent (79-30%)"
Orphanet records absent fingernail as frequent.
Aplasia of distal finger phalanx HP:0009881 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is aplasia of distal finger phalanx (HP:0009881). HP:0009881 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:25915598 SUPPORT Human Clinical
"Zimmermann-Laband syndrome (ZLS) is a developmental disorder characterized by facial dysmorphism with gingival enlargement, intellectual disability, hypoplasia or aplasia of nails and terminal phalanges, and hypertrichosis."
Supports distal-phalanx aplasia as part of the core ZLS phenotype.
Short distal phalanx of finger HP:0009882 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is hypoplastic distal finger phalanx, annotated with Short distal phalanx of finger (HP:0009882). HP:0009882 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:25915598 SUPPORT Human Clinical
"Zimmermann-Laband syndrome (ZLS) is a developmental disorder characterized by facial dysmorphism with gingival enlargement, intellectual disability, hypoplasia or aplasia of nails and terminal phalanges, and hypertrichosis."
Supports terminal-phalanx hypoplasia as part of the core ZLS phenotype.
Large fleshy ears FREQUENT HP:0002265 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is large fleshy ears (HP:0002265). HP:0002265 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0002265 | Large fleshy ears | Frequent (79-30%)"
Orphanet records large fleshy ears as frequent.
Generalized hypertrichosis FREQUENT HP:0004554 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is generalized hypertrichosis (HP:0004554). HP:0004554 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0004554 | Generalized hypertrichosis | Frequent (79-30%)"
Orphanet records generalized hypertrichosis as frequent.
Anterior open-bite malocclusion FREQUENT HP:0009102 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is anterior open-bite malocclusion (HP:0009102). HP:0009102 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0009102 | Anterior open-bite malocclusion | Frequent (79-30%)"
Orphanet records anterior open-bite malocclusion as frequent.
Thickened ears FREQUENT HP:0009894 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is thickened ears (HP:0009894). HP:0009894 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0009894 | Thickened ears | Frequent (79-30%)"
Orphanet records thickened ears as frequent.
Telecanthus OCCASIONAL HP:0000506 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is telecanthus (HP:0000506). HP:0000506 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0000506 | Telecanthus | Occasional (29-5%)"
Orphanet records telecanthus as occasional.
Long eyelashes OCCASIONAL HP:0000527 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is long eyelashes (HP:0000527). HP:0000527 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0000527 | Long eyelashes | Occasional (29-5%)"
Orphanet records long eyelashes as occasional.
Thick eyebrow OCCASIONAL HP:0000574 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is thick eyebrow (HP:0000574). HP:0000574 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0000574 | Thick eyebrow | Occasional (29-5%)"
Orphanet records thick eyebrow as occasional.
Abnormal external genitalia OCCASIONAL Abnormal external genitalia morphology HP:0000811 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is abnormal external genitalia, annotated with Abnormal external genitalia morphology (HP:0000811). HP:0000811 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0000811 | Abnormal external genitalia | Occasional (29-5%)"
Orphanet records abnormal external genitalia as occasional.
Soft skin OCCASIONAL HP:0000977 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is soft skin (HP:0000977). HP:0000977 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0000977 | Soft skin | Occasional (29-5%)"
Orphanet records soft skin as occasional.
Hallux valgus OCCASIONAL HP:0001822 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is hallux valgus (HP:0001822). HP:0001822 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0001822 | Hallux valgus | Occasional (29-5%)"
Orphanet records hallux valgus as occasional.
Facial hypertrichosis OCCASIONAL HP:0002219 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is facial hypertrichosis (HP:0002219). HP:0002219 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0002219 | Facial hypertrichosis | Occasional (29-5%)"
Orphanet records facial hypertrichosis as occasional.
Abnormal cardiovascular system morphology OCCASIONAL HP:0030680 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is abnormal cardiovascular system morphology (HP:0030680). HP:0030680 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0030680 | Abnormal cardiovascular system morphology | Occasional (29-5%)"
Orphanet records abnormal cardiovascular system morphology as occasional.
Deep plantar creases VERY_RARE HP:0001869 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is deep plantar creases (HP:0001869). HP:0001869 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0001869 | Deep plantar creases | Very rare (<4-1%)"
Orphanet records deep plantar creases as very rare.
Deep palmar crease VERY_RARE HP:0006191 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is deep palmar crease (HP:0006191). HP:0006191 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0006191 | Deep palmar crease | Very rare (<4-1%)"
Orphanet records deep palmar crease as very rare.
Overtubulated long bones VERY_RARE HP:0006391 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is overtubulated long bones (HP:0006391). HP:0006391 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0006391 | Overtubulated long bones | Very rare (<4-1%)"
Orphanet records overtubulated long bones as very rare.
Generalized hyperpigmentation VERY_RARE HP:0007440 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is generalized hyperpigmentation (HP:0007440). HP:0007440 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"HP:0007440 | Generalized hyperpigmentation | Very rare (<4-1%)"
Orphanet records generalized hyperpigmentation as very rare.
🧬

Genetic Associations

3
KCNH1 gain-of-function variants (Causative)
Gene: KCNH1 hgnc:6250 HUGO Gene Nomenclature Committee (hgnc) Relation: this disease-associated gene is this gene This disease-associated gene is KCNH1 (hgnc:6250). hgnc:6250 is a gene from the HUGO Gene Nomenclature Committee.
Show evidence (2 references)
PMID:25915598 SUPPORT Human Clinical
"We report that heterozygous missense mutations in KCNH1 account for a considerable proportion of ZLS."
The study identifies heterozygous KCNH1 missense variants as a common molecular cause.
ORPHA:3473 SUPPORT Other
"KCNH1 | potassium voltage-gated channel subfamily H member 1 | hgnc:6250 | Disease-causing germline mutation(s) in"
Orphanet lists KCNH1 as a disease-causing germline gene for ZLS.
KCNN3 gain-of-function variants (Causative)
Gene: KCNN3 hgnc:6292 HUGO Gene Nomenclature Committee (hgnc) Relation: this disease-associated gene is this gene This disease-associated gene is KCNN3 (hgnc:6292). hgnc:6292 is a gene from the HUGO Gene Nomenclature Committee.
Show evidence (2 references)
PMID:31155282 SUPPORT Human Clinical
"We report de novo missense variants in KCNN3 in three individuals with typical clinical features of ZLS."
The study directly identifies de novo KCNN3 variants in individuals with typical ZLS.
ORPHA:3473 SUPPORT Other
"KCNN3 | potassium calcium-activated channel subfamily N member 3 | hgnc:6292 | Disease-causing germline mutation(s) (gain of function) in"
Orphanet lists gain-of-function KCNN3 disease-causing germline variants for ZLS.
ATP6V1B2 missense variants (Causative)
Gene: ATP6V1B2 hgnc:854 HUGO Gene Nomenclature Committee (hgnc) Relation: this disease-associated gene is this gene This disease-associated gene is ATP6V1B2 (hgnc:854). hgnc:854 is a gene from the HUGO Gene Nomenclature Committee. variant_origin: DE_NOVO
Show evidence (3 references)
PMID:25915598 SUPPORT Human Clinical
"We also identified a recurrent de novo missense change in ATP6V1B2, encoding the B2 subunit of the multimeric vacuolar H(+) ATPase, in two individuals with ZLS."
The study identifies recurrent de novo ATP6V1B2 variants in two ZLS individuals.
ORPHA:3473 SUPPORT Other
"ATP6V1B2 | ATPase H+ transporting V1 subunit B2 | hgnc:854 | Disease-causing germline mutation(s) in"
Orphanet lists ATP6V1B2 as a disease-causing germline gene for ZLS.
PMID:39210597 SUPPORT In Vitro
"We observed a significant higher acidity of lysosomes in all patients’ cell lines compared with control cells, indicating a hyperactive behavior of the proton pumps assembling the mutant B2/C1 subunits."
The tested patient lines, including p.Arg485Pro fibroblasts, showed hyperactive proton pumping and lysosomal hyperacidification.
Variants (1)
ATP6V1B2 p.Arg485Pro Pathogenic
Gene: ATP6V1B2 hgnc:854 HUGO Gene Nomenclature Committee (hgnc) Relation: this variant is in this gene This variant is in ATP6V1B2 (hgnc:854). hgnc:854 is a gene from the HUGO Gene Nomenclature Committee. missense
Recurrent heterozygous de novo missense substitution associated with ZLS2 and directly characterized in primary patient fibroblasts.
Show evidence (2 references)
PMID:39210597 SUPPORT In Vitro
"We investigated the functional consequences of the identified ATP6V1B2 and ATP6V1C1 variants, together with the p.Arg485Pro change in ATP6V1B2"
Directly establishes inclusion of p.Arg485Pro in the functional series.
PMID:39210597 SUPPORT In Vitro
"Consistently, similar levels of endogenous ATP6V1B2 were also found in primary fibroblasts obtained from affected (B2A332V, B2Q376K, and B2R485P) and control individuals (Figure S3)."
Directly identifies the p.Arg485Pro primary patient-fibroblast line.
🗃️

External Assertions

1
Orphanet Zimmermann-Laband syndrome record
Orphanet structured disease record ORPHA:3473
Orphanet's ORPHA:3473 structured record provides the disease definition, neonatal onset, inheritance assertion, epidemiology, cross-references, gene-disease rows, and HPO phenotype rows used in this entry.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"A rare genetic multiple congenital anomalies syndrome characterized by gingival fibromatosis, coarse facial appearance, and absence or hypoplasia of nails or terminal phalanges of hands and feet."
Orphanet defines the core clinical concept curated here.
💊

Medical Actions

2
Gingivectomy and gingivoplasty for gingival fibromatosis
Action: gingivectomyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is gingivectomy (NCIT:C82090). NCIT:C82090 is a clinical intervention from the NCI Thesaurus. Ontology label: Gingivectomy NCIT:C82090
Platform: Surgery
Surgical removal and reshaping of hyperplastic gingiva can expose teeth, improve occlusion, restore dental function, and improve oral aesthetics.
Target Phenotypes: gingival fibromatosis HP:0000169 Human Phenotype Ontology (HP) Relation: this treatment targets this phenotype This treatment targets gingival fibromatosis (HP:0000169). HP:0000169 is a phenotype from the Human Phenotype Ontology. delayed eruption of teeth HP:0000684 Human Phenotype Ontology (HP) Relation: this treatment targets this phenotype This treatment targets delayed eruption of teeth (HP:0000684). HP:0000684 is a phenotype from the Human Phenotype Ontology.
Show evidence (3 references)
PMID:39087232 SUPPORT Human Clinical
"Gingivectomy and gingivoplasty were performed under general anesthesia. After surgery, the gingival appearance improved significantly, and the masticatory function of the teeth was restored."
A ZLS case report documents functional improvement after gingivectomy and gingivoplasty.
PMID:40604848 SUPPORT Human Clinical
"This case illustrates the need for appropriate and early gingivoplasty to prevent teeth impaction and restore dental function."
The proposed protocol supports early gingivoplasty for gingival fibromatosis-associated tooth impaction and dental dysfunction.
PMID:40425216 SUPPORT Human Clinical
"In this case report, the surgical management of HGF associated with the Zimmermann-Laband syndrome was successfully carried out using three different methods: conventional gingivectomy, electrocautery and diode laser gingivectomy."
Independently documents successful gingivectomy approaches in ZLS-associated gingival fibromatosis.
Myofunctional and speech-language oral therapy
Action: speech language therapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is speech language therapy (NCIT:C159273). NCIT:C159273 is a clinical intervention from the NCI Thesaurus. Ontology label: Speech Language Therapy NCIT:C159273
Platform: Behavioral / lifestyle
Myofunctional and speech-language therapy may support biting, chewing, and tongue-function rehabilitation before or alongside gingivoplasty.
Show evidence (1 reference)
PMID:40604848 SUPPORT Human Clinical
"The first step of oral treatment consisted of myofunctional and speech/language therapy to stimulate biting and chewing. It also helped with the rehabilitation of proper tongue function."
The case protocol supports supportive oral therapy to improve biting, chewing, and tongue function.
🔬

Diagnosis

2
Clinical syndrome recognition
Clinical recognition is based on the combination of gingival fibromatosis, coarse facial appearance, hypertrichosis, neurodevelopmental involvement, and distal nail or phalangeal abnormalities.
examination by clinical professional NCIT:C20989 NCI Thesaurus (NCIT)
Show evidence (1 reference)
PMID:25915598 SUPPORT Human Clinical
"Zimmermann-Laband syndrome (ZLS) is a developmental disorder characterized by facial dysmorphism with gingival enlargement, intellectual disability, hypoplasia or aplasia of nails and terminal phalanges, and hypertrichosis."
The molecular genetics paper summarizes the core clinical-recognition pattern.
Molecular genetic testing
Sequencing can identify pathogenic variants in KCNH1, KCNN3, or ATP6V1B2 and distinguish ZLS from overlapping potassium-channel dysmorphism syndromes.
genetic testing NCIT:C15709 NCI Thesaurus (NCIT)
Show evidence (3 references)
PMID:39087232 SUPPORT Human Clinical
"A novel pathogenic variant in the KCNH1 gene was identified using whole-exome sequencing to substantiate our preliminary diagnosis."
Whole-exome sequencing confirmed a KCNH1 pathogenic variant after clinical suspicion of ZLS.
PMID:25915598 SUPPORT Human Clinical
"We also identified a recurrent de novo missense change in ATP6V1B2, encoding the B2 subunit of the multimeric vacuolar H(+) ATPase, in two individuals with ZLS."
Supports ATP6V1B2 testing in molecular confirmation of ZLS2.
PMID:31155282 SUPPORT Human Clinical
"We report de novo missense variants in KCNN3 in three individuals with typical clinical features of ZLS."
Supports KCNN3 testing in molecular confirmation of ZLS3.
📊

Prevalence

1
Worldwide
Point Prevalence ≤0.1 per 100,000 <1 in 1,000,000
Orphanet reports a worldwide point prevalence below one per million.
Show evidence (1 reference)
ORPHA:3473 SUPPORT Other
"<1 / 1 000 000 | Worldwide | Point prevalence | PMID:23994350"
Orphanet supplies the point-prevalence class and geographic scope.
🔀

Differential Diagnoses

4

Conditions with similar clinical presentations that must be differentiated from Zimmermann-Laband Syndrome:

Temple-Baraitser syndrome MONDO:0012735
Overlapping Features Temple-Baraitser syndrome and ZLS1 share KCNH1 gain-of-function variants, intellectual disability, epilepsy, facial dysmorphism, and nail anomalies. Gingival enlargement and hypertrichosis favor the ZLS gestalt, whereas broad thumbs and great toes with absent or hypoplastic nails favor TBS; phenotype overlap can make molecular results more informative than labels.
Distinguishing Features
  • Gingival enlargement and hypertrichosis favor Zimmermann-Laband syndrome.
  • Broad thumbs and great toes with absent or hypoplastic nails favor Temple-Baraitser syndrome.
  • KCNH1-related phenotypes overlap and may not satisfy either classic gestalt.
Show evidence (1 reference)
PMID:26264464 SUPPORT Human Clinical
"TMBTS is characterized by intellectual disability (ID), epilepsy, dysmorphic facial features, broad thumbs and great toes with absent/hypoplastic nails. ZLS is characterized by facial dysmorphism including coarsening of the face and a large nose, gingival enlargement, ID, hypoplasia of terminal..."
States the overlapping and distinguishing clinical features of TBS and ZLS.
Dominant deafness-onychodystrophy syndrome MONDO:0007420
Overlapping Features ATP6V1B2-associated dominant deafness-onychodystrophy (DDOD) syndrome is an allelic differential within the same dominant V-ATPase clinical continuum. Sensorineural deafness and onychodystrophy with digital anomalies predominate in DDOD, whereas gingival hypertrophy and hypertrichosis are more characteristic of ZLS2.
Distinguishing Features
  • Predominant sensorineural deafness, onychodystrophy, and characteristic digital anomalies favor DDOD.
  • Gingival hypertrophy and hypertrichosis favor ZLS2 because they are not usually reported in DDOD or DOORS.
  • ATP6V1B2 genotype and the broader phenotype should be interpreted as a continuum rather than as an absolute boundary.
Show evidence (3 references)
PMID:39210597 SUPPORT Human Clinical
"Specifically, individuals with DDOD syndrome primarily share sensorineural deafness and onychodystrophy with digital anomalies characterized by bulbous fingertips of digits, and finger-like thumbs/triphalangeal thumb."
Directly states the predominant DDOD distinguishing features.
PMID:39210597 SUPPORT Human Clinical
"Facial features of DOORS syndrome have a significant overlap with ZLS, a condition also associated with organomegaly, gingival hypertrophy, and hypertrichosis, which are not usually reported in DDOD and DOORS syndromes."
Supports gingival hypertrophy and hypertrichosis, but not coarse facies, as ZLS-favoring distinctions.
PMID:39210597 SUPPORT Human Clinical
"The present findings further support these observations, documenting the presence of a phenotypic continuum among these disorders."
Supports interpreting DDOD and ZLS2 as a clinical continuum rather than an absolute boundary.
DOORS syndrome MONDO:0009079
Overlapping Features DOORS syndrome overlaps ATP6V1B2-related ZLS2 through deafness, nail and distal-phalangeal abnormalities, neurodevelopmental impairment, and seizures. Osteodystrophy and the deafness-onychodystrophy-neurologic constellation favor DOORS, while gingival hypertrophy and hypertrichosis favor ZLS2. The cited ATP6V1B2 study places these presentations on a clinically variable continuum.
Distinguishing Features
  • Sensorineural hearing loss, onychodystrophy, distal digital abnormalities, osteodystrophy, and seizures favor DOORS syndrome.
  • Gingival hypertrophy and hypertrichosis favor ZLS2 because they are not usually reported in DDOD or DOORS.
  • The broader phenotype should be interpreted as a continuum rather than as an absolute boundary.
Show evidence (4 references)
PMID:39210597 SUPPORT Human Clinical
"DOORS syndrome shares sensorineural hearing loss, onychodystrophy, and digital abnormalities (i.e., triphalangeal thumb and hypoplastic/absent distal phalanges) with DDOD syndrome."
Directly states the shared DOORS distinguishing features.
PMID:39210597 SUPPORT Human Clinical
"Osteodystrophy is reported in most cases as well as a neurodevelopmental/neurological involvement, which includes seizures."
Directly supports osteodystrophy and seizures as DOORS-favoring features.
PMID:39210597 SUPPORT Human Clinical
"Facial features of DOORS syndrome have a significant overlap with ZLS, a condition also associated with organomegaly, gingival hypertrophy, and hypertrichosis, which are not usually reported in DDOD and DOORS syndromes."
Supports gingival hypertrophy and hypertrichosis, but not coarse facies, as ZLS-favoring distinctions.
+ 1 more reference
{ }

Source YAML

click to show 
name: Zimmermann-Laband Syndrome
category: Mendelian
creation_date: "2026-05-09T21:19:51Z"
synonyms:
- Laband syndrome
- Gingival fibromatosis-hepatosplenomegaly-other anomalies syndrome
- ZLS
description: >
  Zimmermann-Laband syndrome is a rare multiple congenital anomalies and
  neurodevelopmental disorder characterized by gingival fibromatosis, coarse
  facial appearance, hypertrichosis, intellectual disability, and hypoplastic or
  absent nails or terminal phalanges. It is genetically heterogeneous, with
  pathogenic variants in KCNH1, KCNN3, and ATP6V1B2 reported in affected
  individuals.
disease_term:
  preferred_term: Zimmermann-Laband syndrome
  term:
    id: MONDO:0000200
    label: Zimmermann-Laband syndrome
has_subtypes:
- name: ZLS1
  display_name: Zimmermann-Laband syndrome type 1 (KCNH1-related)
  description: >
    KCNH1-related ZLS is caused by heterozygous gain-of-function missense
    variants in the Kv10.1 voltage-gated potassium channel.
  subtype_term:
    preferred_term: Zimmermann-Laband syndrome 1
    term:
      id: MONDO:0024526
      label: Zimmermann-Laband syndrome 1
  genes:
  - preferred_term: KCNH1
    term:
      id: hgnc:6250
      label: KCNH1
  evidence:
  - reference: PMID:25915598
    reference_title: Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We report that heterozygous missense mutations in KCNH1 account for a considerable proportion of ZLS."
    explanation: Establishes the KCNH1-related molecular subtype.
  - reference: PMID:25915598
    reference_title: Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "These data support a gain-of-function effect for all ZLS-associated KCNH1 mutants."
    explanation: Functional studies support the gain-of-function wording for the KCNH1-related subtype.
- name: ZLS2
  display_name: Zimmermann-Laband syndrome type 2 (ATP6V1B2-related)
  description: >
    ATP6V1B2-related ZLS is caused by de novo monoallelic variants affecting the
    B2 subunit of the vacuolar proton ATPase. Functional studies of p.Arg485Pro
    and other tested dominant ATP6V1B2 substitutions support increased V-ATPase
    activity, while clinical expression spans a ZLS-DDOD-DOORS continuum.
  subtype_term:
    preferred_term: Zimmermann-Laband syndrome 2
    term:
      id: MONDO:0014646
      label: Zimmermann-Laband syndrome 2
  genes:
  - preferred_term: ATP6V1B2
    term:
      id: hgnc:854
      label: ATP6V1B2
  evidence:
  - reference: PMID:25915598
    reference_title: Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We also identified a recurrent de novo missense change in ATP6V1B2, encoding the B2 subunit of the multimeric vacuolar H(+) ATPase, in two individuals with ZLS."
    explanation: Establishes the ATP6V1B2-related molecular subtype.
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "We investigated the functional consequences of the identified ATP6V1B2 and ATP6V1C1 variants, together with the p.Arg485Pro change in ATP6V1B2"
    explanation: Establishes that p.Arg485Pro was included in the functional series.
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "We observed a significant higher acidity of lysosomes in all patients’ cell lines compared with control cells, indicating a hyperactive behavior of the proton pumps assembling the mutant B2/C1 subunits."
    explanation: The p.Arg485Pro line was among the tested patient lines showing hyperactive proton pumping and lysosomal hyperacidification.
- name: ZLS3
  display_name: Zimmermann-Laband syndrome type 3 (KCNN3-related)
  description: >
    KCNN3-related ZLS is caused by de novo gain-of-function missense variants
    in the SK3 calcium-activated potassium channel.
  subtype_term:
    preferred_term: Zimmermann-Laband syndrome 3
    term:
      id: MONDO:0032854
      label: Zimmermann-Laband syndrome 3
  genes:
  - preferred_term: KCNN3
    term:
      id: hgnc:6292
      label: KCNN3
  evidence:
  - reference: PMID:31155282
    reference_title: Gain-of-Function Mutations in KCNN3 Encoding the Small-Conductance Ca(2+)-Activated K(+) Channel SK3 Cause Zimmermann-Laband Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We report de novo missense variants in KCNN3 in three individuals with typical clinical features of ZLS."
    explanation: Establishes the KCNN3-related molecular subtype.
  - reference: PMID:31155282
    reference_title: Gain-of-Function Mutations in KCNN3 Encoding the Small-Conductance Ca(2+)-Activated K(+) Channel SK3 Cause Zimmermann-Laband Syndrome.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Patch-clamp whole-cell recordings of KCNN3 channel-expressing CHO cells demonstrated that disease-associated mutations result in gain of function of the mutant channels, characterized by increased Ca2+ sensitivity leading to faster and more complete activation of KCNN3 mutant channels."
    explanation: Functional studies support the gain-of-function wording for the KCNN3-related subtype.
mappings:
  mondo_mappings:
  - term:
      id: MONDO:0000200
      label: Zimmermann-Laband syndrome
    mapping_predicate: skos:exactMatch
    mapping_source: MONDO
  - term:
      id: MONDO:0024526
      label: Zimmermann-Laband syndrome 1
    mapping_predicate: skos:narrowMatch
    mapping_source: MONDO
    mapping_justification: >
      MONDO:0024526 (OMIM:135500) is_a the MONDO:0000200 anchor of this entry and
      is defined as its KCNH1 subtype (intersection_of RO:0004003 HGNC:6250; also
      is_a MONDO:0100485 KCNH1 associated disorder). This entry curates KCNH1
      gain-of-function variants alongside the KCNN3 and ATP6V1B2 aetiologies, so
      the KCNH1 child term is covered here. narrowMatch rather than exactMatch
      because the anchor also subsumes the non-KCNH1 forms.
  - term:
      id: MONDO:0014646
      label: Zimmermann-Laband syndrome 2
    mapping_predicate: skos:narrowMatch
    mapping_source: MONDO
    mapping_justification: ATP6V1B2-related molecular subtype of this umbrella entry.
  - term:
      id: MONDO:0032854
      label: Zimmermann-Laband syndrome 3
    mapping_predicate: skos:narrowMatch
    mapping_source: MONDO
    mapping_justification: KCNN3-related molecular subtype of this umbrella entry.
parents:
- hereditary disease
- multiple congenital anomalies syndrome
- syndromic neurodevelopmental disorder
- potassium channelopathy
external_assertions:
- name: Orphanet Zimmermann-Laband syndrome record
  source: Orphanet
  assertion_type: structured_disease_record
  external_id: ORPHA:3473
  url: http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=3473
  description: >
    Orphanet's ORPHA:3473 structured record provides the disease definition,
    neonatal onset, inheritance assertion, epidemiology, cross-references,
    gene-disease rows, and HPO phenotype rows used in this entry.
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "A rare genetic multiple congenital anomalies syndrome characterized by gingival fibromatosis, coarse facial appearance, and absence or hypoplasia of nails or terminal phalanges of hands and feet."
    explanation: Orphanet defines the core clinical concept curated here.
prevalence:
- population: Worldwide
  measure_type: POINT_PREVALENCE
  prevalence_class: BELOW_1_IN_1000000
  rate_high: 0.1
  notes: Orphanet reports a worldwide point prevalence below one per million.
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "<1 / 1 000 000 | Worldwide | Point prevalence | PMID:23994350"
    explanation: Orphanet supplies the point-prevalence class and geographic scope.
inheritance:
- name: Autosomal dominant inheritance
  description: >
    Most molecularly solved cases are sporadic or de novo dominant potassium
    channelopathy cases, although older literature and Orphanet note familial
    aggregation and autosomal-recessive hypotheses.
  inheritance_term:
    preferred_term: Autosomal dominant inheritance
    term:
      id: HP:0000006
      label: Autosomal dominant inheritance
  evidence:
  - reference: PMID:23994350
    reference_title: Clinical and genetic study of two patients with Zimmermann-Laband syndrome and literature review.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "An autosomal dominant mutation with high mutation rate and rare instances of germinal mosaicism seems the most likely inheritance pattern."
    explanation: Literature review of sporadic and familial cases supports autosomal dominant inheritance with possible germline mosaicism.
  - reference: PMID:31155282
    reference_title: Gain-of-Function Mutations in KCNN3 Encoding the Small-Conductance Ca(2+)-Activated K(+) Channel SK3 Cause Zimmermann-Laband Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We report de novo missense variants in KCNN3 in three individuals with typical clinical features of ZLS."
    explanation: De novo KCNN3 variants in typical ZLS cases support dominant inheritance for a molecular subtype.
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: REFUTE
    evidence_source: OTHER
    snippet: |-
      ## Inheritance

      - Autosomal recessive

      ## Natural history
    explanation: >
      Orphanet retains an autosomal-recessive assertion from the pre-molecular
      literature; this conflicts with the de novo dominant molecular evidence
      and is retained to make the disagreement explicit.
pathophysiology:
- name: Increased potassium-channel conductance
  biological_scale: MOLECULAR
  mechanism_confidence: ESTABLISHED
  description: >
    ZLS-associated KCNH1 and KCNN3 missense variants increase potassium-channel
    activity or conductance, defining a syndromic neurodevelopmental
    potassium-channelopathy mechanism for ZLS1 and ZLS3.
  role: trigger
  subtypes: [ZLS1, ZLS3]
  genes:
  - preferred_term: KCNH1
    term: {id: hgnc:6250, label: KCNH1}
  - preferred_term: KCNN3
    term: {id: hgnc:6292, label: KCNN3}
  biological_processes:
  - preferred_term: potassium ion transmembrane transport
    term: {id: GO:0071805, label: potassium ion transmembrane transport}
    modifier: INCREASED
  molecular_functions:
  - preferred_term: voltage-gated potassium channel activity
    term: {id: GO:0005249, label: voltage-gated potassium channel activity}
    modifier: INCREASED
  - preferred_term: calcium-activated potassium channel activity
    term: {id: GO:0015269, label: calcium-activated potassium channel activity}
    modifier: INCREASED
  evidence:
  - reference: PMID:25915598
    reference_title: Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "These data support a gain-of-function effect for all ZLS-associated KCNH1 mutants."
    explanation: Patch-clamp data support increased KCNH1 function.
  - reference: PMID:31155282
    reference_title: Gain-of-Function Mutations in KCNN3 Encoding the Small-Conductance Ca(2+)-Activated K(+) Channel SK3 Cause Zimmermann-Laband Syndrome.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Patch-clamp whole-cell recordings of KCNN3 channel-expressing CHO cells demonstrated that disease-associated mutations result in gain of function of the mutant channels, characterized by increased Ca2+ sensitivity leading to faster and more complete activation of KCNN3 mutant channels."
    explanation: CHO-cell patch-clamp data support increased KCNN3 function.
  - reference: PMID:33594261
    reference_title: "Syndromic disorders caused by gain-of-function variants in KCNH1, KCNK4, and KCNN3-a subgroup of K(+) channelopathies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We suggest to combine the phenotypes and define a new subgroup of potassium channelopathies caused by increased K+ conductance, referred to as syndromic neurodevelopmental K+ channelopathies due to dominant variants in KCNH1, KCNK4, or KCNN3."
    explanation: Places KCNH1- and KCNN3-related ZLS in a gain-of-conductance group.
  downstream:
  - target: KCNH1-related ciliary signaling disruption
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    hypothesis_groups: [ciliary_hedgehog_extraneurological]
    evidence:
    - reference: PMID:35639255
      reference_title: Potassium Channel KCNH1 Activating Variants Cause Altered Functional and Morphological Ciliogenesis.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "KCNH1 variants would confer a gain of function effect with increased channel activity that, in turn, would induce primary cilia disassembly and cause altered cilia structure"
      explanation: The authors propose increased KCNH1 activity as the route to ciliary disassembly; the indirect edge does not claim direct intervention proof.
  - target: Neurodevelopmental dysfunction
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:33594261
      reference_title: "Syndromic disorders caused by gain-of-function variants in KCNH1, KCNK4, and KCNN3-a subgroup of K(+) channelopathies."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "There is notable overlap in the phenotypic findings of these syndromes associated with dominant KCNN3, KCNH1, and KCNK4 variants, sharing developmental delay and/or ID, coarse facial features, gingival enlargement, distal digital hypoplasia, and hypertrichosis."
      explanation: Links the gain-of-conductance group to developmental delay/ID, but not the intervening causal steps.
  - target: Gingival and dental developmental overgrowth
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:33594261
      reference_title: "Syndromic disorders caused by gain-of-function variants in KCNH1, KCNK4, and KCNN3-a subgroup of K(+) channelopathies."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "There is notable overlap in the phenotypic findings of these syndromes associated with dominant KCNN3, KCNH1, and KCNK4 variants, sharing developmental delay and/or ID, coarse facial features, gingival enlargement, distal digital hypoplasia, and hypertrichosis."
      explanation: Links the channelopathy group to gingival enlargement, while intermediates remain unknown.
  - target: Distal digital and nail developmental abnormality
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:33594261
      reference_title: "Syndromic disorders caused by gain-of-function variants in KCNH1, KCNK4, and KCNN3-a subgroup of K(+) channelopathies."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "There is notable overlap in the phenotypic findings of these syndromes associated with dominant KCNN3, KCNH1, and KCNK4 variants, sharing developmental delay and/or ID, coarse facial features, gingival enlargement, distal digital hypoplasia, and hypertrichosis."
      explanation: Links the channelopathy group to distal digital hypoplasia, while intermediates remain unknown.
  - target: Coarse facial features
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:33594261
      reference_title: "Syndromic disorders caused by gain-of-function variants in KCNH1, KCNK4, and KCNN3-a subgroup of K(+) channelopathies."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "There is notable overlap in the phenotypic findings of these syndromes associated with dominant KCNN3, KCNH1, and KCNK4 variants, sharing developmental delay and/or ID, coarse facial features, gingival enlargement, distal digital hypoplasia, and hypertrichosis."
      explanation: Links the gain-of-conductance group to coarse facial features, while intermediates remain unknown.
  - target: Generalized hypertrichosis
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:33594261
      reference_title: "Syndromic disorders caused by gain-of-function variants in KCNH1, KCNK4, and KCNN3-a subgroup of K(+) channelopathies."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "There is notable overlap in the phenotypic findings of these syndromes associated with dominant KCNN3, KCNH1, and KCNK4 variants, sharing developmental delay and/or ID, coarse facial features, gingival enlargement, distal digital hypoplasia, and hypertrichosis."
      explanation: Links the gain-of-conductance group to hypertrichosis, while intermediates remain unknown.
- name: ATP6V1B2 p.Arg485Pro hyperactive V-ATPase
  biological_scale: MOLECULAR
  mechanism_confidence: ESTABLISHED
  description: >
    The recurrent de novo ATP6V1B2 p.Arg485Pro ZLS2 substitution produces a
    hyperactive vacuolar H+ ATPase state in patient-derived fibroblasts, with
    increased proton-pumping activity and lysosomal acidification. This
    experimentally demonstrated gain of function supersedes the earlier
    computational complex-assembly prediction as the proximal mechanism.
  role: trigger
  subtypes: [ZLS2]
  genes:
  - preferred_term: ATP6V1B2
    term: {id: hgnc:854, label: ATP6V1B2}
  cell_types:
  - preferred_term: dermal fibroblast
    term: {id: CL:0002551, label: fibroblast of dermis}
  genetic_context:
    gene:
      preferred_term: ATP6V1B2
      term: {id: hgnc:854, label: ATP6V1B2}
    allele_type: missense
    variant_origin: DE_NOVO
    zygosity: HETEROZYGOUS
    functional_impact_category: GAIN_OF_FUNCTION
    description: >
      The recurrent ZLS2 allele p.Arg485Pro was tested in primary patient
      fibroblasts and is included among the dominant ATP6V1B2 substitutions
      that increased V-ATPase proton-pump activity.
  biological_processes:
  - preferred_term: vacuolar acidification
    term: {id: GO:0007035, label: vacuolar acidification}
    modifier: INCREASED
  molecular_functions:
  - preferred_term: proton transmembrane transporter activity
    term: {id: GO:0015078, label: proton transmembrane transporter activity}
    modifier: INCREASED
  evidence:
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "We investigated the functional consequences of the identified ATP6V1B2 and ATP6V1C1 variants, together with the p.Arg485Pro change in ATP6V1B2"
    explanation: Establishes that p.Arg485Pro was included in the functional series.
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "We observed a significant higher acidity of lysosomes in all patients’ cell lines compared with control cells, indicating a hyperactive behavior of the proton pumps assembling the mutant B2/C1 subunits."
    explanation: The tested patient lines, including the p.Arg485Pro fibroblasts, showed hyperactive proton pumping and lysosomal hyperacidification.
  downstream:
  - target: Abnormal lysosomal morphology
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:39210597
      reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "Consistently, similar levels of endogenous ATP6V1B2 were also found in primary fibroblasts obtained from affected (B2A332V, B2Q376K, and B2R485P) and control individuals (Figure S3)."
      explanation: Establishes that the primary patient-fibroblast series included p.Arg485Pro.
    - reference: PMID:39210597
      reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "Notably, a marked increase in the size and number of lysosomes in cells endogenously expressing each of the tested B2 and C1 mutants was observed by immunofluorescence analysis and western blot analyses (Figures 2C and 2D), as observed in lysosomal storage disorders."
      explanation: The tested series included p.Arg485Pro patient fibroblasts and showed increased lysosome size and number; intermediates from hyperacidification remain unresolved.
  - target: Lysosomal substrate accumulation
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:39210597
      reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "Consistently, similar levels of endogenous ATP6V1B2 were also found in primary fibroblasts obtained from affected (B2A332V, B2Q376K, and B2R485P) and control individuals (Figure S3)."
      explanation: Establishes that the primary patient-fibroblast series included p.Arg485Pro.
    - reference: PMID:39210597
      reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "Analyses performed using specific probes (i.e., BTR ceramide and Filipin) showed a significantly increased storage of both substrates in all tested patients’ cell lines compared with controls cells (Figures 3A-3D), suggesting a generalized defective hydrolytic activity of lysosomal enzymes possibly as a result of an altered vacuolar ATPase proton function."
      explanation: All tested patient lines, including p.Arg485Pro fibroblasts, showed cholesterol and ceramide storage; causal intermediates remain unresolved.
  - target: Impaired autophagic flux
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:39210597
      reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "Consistently, similar levels of endogenous ATP6V1B2 were also found in primary fibroblasts obtained from affected (B2A332V, B2Q376K, and B2R485P) and control individuals (Figure S3)."
      explanation: Establishes that the primary patient-fibroblast series included p.Arg485Pro.
    - reference: PMID:39210597
      reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "Immunofluorescence and western blot analysis using an anti LC3I/II antibody as probe showed a significant accumulation of autophagosomes at steady state condition as well as after autophagy flux induction with EBSS in all tested patients’ fibroblasts compared with control cells (Figures 6A-6C, S5, and S6)."
      explanation: All tested patient fibroblasts, including the p.Arg485Pro line, accumulated autophagosomes; the bridge from hyperacidification remains unresolved.
  - target: ATP6V1B2-related altered ciliogenesis
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:39210597
      reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "Consistently, similar levels of endogenous ATP6V1B2 were also found in primary fibroblasts obtained from affected (B2A332V, B2Q376K, and B2R485P) and control individuals (Figure S3)."
      explanation: Establishes that the primary patient-fibroblast series included p.Arg485Pro.
    - reference: PMID:39210597
      reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "The analysis performed in starved fibroblasts revealed the presence of aberrant primary cilium formation in all cell lines (Figure 7)."
      explanation: All tested patient fibroblast lines, including p.Arg485Pro, showed aberrant cilium formation; the intervening route from pump hyperactivity remains unresolved.
  - target: Neurodevelopmental dysfunction
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:39210597
      reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "This work identifies ATP6V1C1 as a new gene associated with a neurodevelopmental phenotype resembling DOORS syndrome, documents the occurrence of a phenotypic continuum between ZLS, and DDOD and DOORS syndromes, and classify these conditions as lysosomal disorders."
      explanation: Supports the ATP6V1B2-associated clinical continuum, while the route from fibroblast lysosomal dysfunction to neurodevelopment remains unresolved.
  - target: Distal digital and nail developmental abnormality
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:25915598
      reference_title: Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "We also identified a recurrent de novo missense change in ATP6V1B2, encoding the B2 subunit of the multimeric vacuolar H(+) ATPase, in two individuals with ZLS."
      explanation: Identifies p.Arg485Pro in people with ZLS, while the route to distal developmental anomalies remains unresolved.
    - reference: PMID:25915598
      reference_title: Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Zimmermann-Laband syndrome (ZLS) is a developmental disorder characterized by facial dysmorphism with gingival enlargement, intellectual disability, hypoplasia or aplasia of nails and terminal phalanges, and hypertrichosis."
      explanation: Establishes the distal nail and phalanx phenotype at the syndrome level without asserting a direct lysosome-to-tissue mechanism.
- name: Abnormal lysosomal morphology
  biological_scale: CELLULAR
  mechanism_confidence: ESTABLISHED
  description: >
    Primary fibroblasts carrying ATP6V1B2 p.Arg485Pro showed increased numbers
    and size of lysosomes and aberrant vesicular ultrastructure.
  role: effector
  subtypes: [ZLS2]
  cell_types:
  - preferred_term: dermal fibroblast
    term: {id: CL:0002551, label: fibroblast of dermis}
  cellular_components:
  - preferred_term: lysosome
    term: {id: GO:0005764, label: lysosome}
  evidence:
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Consistently, similar levels of endogenous ATP6V1B2 were also found in primary fibroblasts obtained from affected (B2A332V, B2Q376K, and B2R485P) and control individuals (Figure S3)."
    explanation: Establishes that the primary-fibroblast series included p.Arg485Pro.
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Notably, a marked increase in the size and number of lysosomes in cells endogenously expressing each of the tested B2 and C1 mutants was observed by immunofluorescence analysis and western blot analyses (Figures 2C and 2D), as observed in lysosomal storage disorders."
    explanation: All tested lines, including p.Arg485Pro fibroblasts, showed increased lysosome size and number.
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "In particular, in fibroblasts expressing B2A322V and B2R485P many of these vesicles seemed to be partially fused (Figures 5E and 5F) or in close proximity to each other (Figures 5I–5L)."
    explanation: Directly identifies abnormal vesicular ultrastructure in p.Arg485Pro fibroblasts.
- name: Lysosomal substrate accumulation
  biological_scale: CELLULAR
  mechanism_confidence: ESTABLISHED
  description: >
    Patient-derived ATP6V1B2 p.Arg485Pro fibroblasts accumulated lysosomal
    substrates, consistent with a cellular storage phenotype despite increased
    acidification.
  role: effector
  subtypes: [ZLS2]
  cell_types:
  - preferred_term: dermal fibroblast
    term: {id: CL:0002551, label: fibroblast of dermis}
  cellular_components:
  - preferred_term: lysosome
    term: {id: GO:0005764, label: lysosome}
  evidence:
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Consistently, similar levels of endogenous ATP6V1B2 were also found in primary fibroblasts obtained from affected (B2A332V, B2Q376K, and B2R485P) and control individuals (Figure S3)."
    explanation: Establishes that the tested primary-fibroblast series included p.Arg485Pro.
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Analyses performed using specific probes (i.e., BTR ceramide and Filipin) showed a significantly increased storage of both substrates in all tested patients’ cell lines compared with controls cells (Figures 3A-3D), suggesting a generalized defective hydrolytic activity of lysosomal enzymes possibly as a result of an altered vacuolar ATPase proton function."
    explanation: All tested patient lines, including the p.Arg485Pro fibroblasts, accumulated cholesterol and ceramide.
- name: Impaired autophagic flux
  biological_scale: CELLULAR
  mechanism_confidence: ESTABLISHED
  description: >
    ATP6V1B2 p.Arg485Pro patient fibroblasts showed autophagosome accumulation
    and defective autophagic flux.
  role: effector
  subtypes: [ZLS2]
  cell_types:
  - preferred_term: dermal fibroblast
    term: {id: CL:0002551, label: fibroblast of dermis}
  biological_processes:
  - preferred_term: autophagic process
    term: {id: GO:0006914, label: autophagy}
    modifier: DECREASED
  evidence:
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Consistently, similar levels of endogenous ATP6V1B2 were also found in primary fibroblasts obtained from affected (B2A332V, B2Q376K, and B2R485P) and control individuals (Figure S3)."
    explanation: Establishes that the tested primary-fibroblast series included p.Arg485Pro.
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Immunofluorescence and western blot analysis using an anti LC3I/II antibody as probe showed a significant accumulation of autophagosomes at steady state condition as well as after autophagy flux induction with EBSS in all tested patients’ fibroblasts compared with control cells (Figures 6A-6C, S5, and S6)."
    explanation: All tested patient fibroblasts, including the p.Arg485Pro line, accumulated autophagosomes during the impaired flux.
- name: ATP6V1B2-related altered ciliogenesis
  biological_scale: CELLULAR
  mechanism_confidence: ESTABLISHED
  description: >
    Primary fibroblasts carrying ATP6V1B2 p.Arg485Pro formed abnormally short
    or absent primary cilia after starvation.
  role: effector
  subtypes: [ZLS2]
  cell_types:
  - preferred_term: dermal fibroblast
    term: {id: CL:0002551, label: fibroblast of dermis}
  biological_processes:
  - preferred_term: cilium assembly
    term: {id: GO:0060271, label: cilium assembly}
    modifier: DYSREGULATED
  cellular_components:
  - preferred_term: cilium
    term: {id: GO:0005929, label: cilium}
  evidence:
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Consistently, similar levels of endogenous ATP6V1B2 were also found in primary fibroblasts obtained from affected (B2A332V, B2Q376K, and B2R485P) and control individuals (Figure S3)."
    explanation: Establishes that the tested primary-fibroblast series included p.Arg485Pro.
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Specifically, the cilium was either shorter compared with control cells or absent (dot cilium), documenting a pleiotropic effect of each of the tested variants also involving cilium biogenesis."
    explanation: Each tested variant, including p.Arg485Pro, produced short or absent cilia in primary fibroblasts.
- name: KCNH1-related ciliary signaling disruption
  biological_scale: CELLULAR
  mechanism_confidence: HYPOTHETICAL
  description: >
    KCNH1 localizes to the base of primary cilia in cultured human cells, and
    pathogenic missense variants perturb cilium morphology, assembly and
    disassembly, and Sonic Hedgehog signaling. Its proposed link to the
    extraneurological ZLS1 phenotype remains an emerging hypothesis.
  role: effector
  subtypes: [ZLS1]
  genes:
  - preferred_term: KCNH1
    term: {id: hgnc:6250, label: KCNH1}
  cell_types:
  - preferred_term: dermal fibroblast
    term: {id: CL:0002551, label: fibroblast of dermis}
  - preferred_term: retinal pigment epithelial cell
    term: {id: CL:0002586, label: retinal pigment epithelial cell}
  biological_processes:
  - preferred_term: cilium assembly
    term: {id: GO:0060271, label: cilium assembly}
    modifier: DYSREGULATED
  - preferred_term: smoothened signaling pathway
    term: {id: GO:0007224, label: smoothened signaling pathway}
    modifier: DYSREGULATED
  cellular_components:
  - preferred_term: cilium
    term: {id: GO:0005929, label: cilium}
  evidence:
  - reference: PMID:35639255
    reference_title: Potassium Channel KCNH1 Activating Variants Cause Altered Functional and Morphological Ciliogenesis.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "In this work, we provide evidence that KCNH1 localizes at the base of the cilium in pre-ciliary vesicles and ciliary pocket of human dermal fibroblasts and retinal pigment epithelial (hTERT RPE1) cells and that the pathogenic missense variants (L352V and R330Q; NP_002229.1) perturb cilia morphology, assembly/disassembly, and Sonic Hedgehog signaling, disclosing a multifaceted role of the protein."
    explanation: Demonstrates altered ciliogenesis/signaling in cultured human cells.
  downstream:
  - target: Gingival and dental developmental overgrowth
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    hypothesis_groups: [ciliary_hedgehog_extraneurological]
    evidence:
    - reference: PMID:35639255
      reference_title: Potassium Channel KCNH1 Activating Variants Cause Altered Functional and Morphological Ciliogenesis.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "The study of KCNH1 localization, its functions related to primary cilia, and the alterations introduced by mutations in ciliogenesis, cell cycle coordination, cilium morphology, and cilia signaling pathways could help elucidate the molecular mechanisms underlying neurological phenotypes and neurodevelopmental disorders not considered as classical ciliopathies but for which a significant role of primary cilia is emerging."
      explanation: Supports an emerging ciliary mechanism but does not demonstrate gingival causation.
  - target: Distal digital and nail developmental abnormality
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    hypothesis_groups: [ciliary_hedgehog_extraneurological]
    evidence:
    - reference: PMID:35639255
      reference_title: Potassium Channel KCNH1 Activating Variants Cause Altered Functional and Morphological Ciliogenesis.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "The study of KCNH1 localization, its functions related to primary cilia, and the alterations introduced by mutations in ciliogenesis, cell cycle coordination, cilium morphology, and cilia signaling pathways could help elucidate the molecular mechanisms underlying neurological phenotypes and neurodevelopmental disorders not considered as classical ciliopathies but for which a significant role of primary cilia is emerging."
      explanation: Supports an emerging ciliary mechanism but does not demonstrate distal-anomaly causation.
- name: Neurodevelopmental dysfunction
  biological_scale: ORGANISM
  description: >
    Molecularly heterogeneous ZLS converges on developmental delay or
    intellectual disability and variable seizure susceptibility.
  role: downstream_pathology
  locations:
  - preferred_term: central nervous system
    term: {id: UBERON:0001017, label: central nervous system}
  evidence:
  - reference: PMID:33594261
    reference_title: "Syndromic disorders caused by gain-of-function variants in KCNH1, KCNK4, and KCNN3-a subgroup of K(+) channelopathies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "There is notable overlap in the phenotypic findings of these syndromes associated with dominant KCNN3, KCNH1, and KCNK4 variants, sharing developmental delay and/or ID, coarse facial features, gingival enlargement, distal digital hypoplasia, and hypertrichosis."
    explanation: Supports developmental delay/ID in the potassium-channel subtypes.
  - reference: PMID:23994350
    reference_title: Clinical and genetic study of two patients with Zimmermann-Laband syndrome and literature review.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Tabulation of clinical features confirmed the core phenotype and identified developmental delay as the unique major clinical problem (occurring in 40% of the cases) with a moderately high risk of epilepsy (13%)."
    explanation: Quantifies developmental delay and epilepsy across historical ZLS cases.
  downstream:
  - target: Global developmental delay
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:23994350
      reference_title: Clinical and genetic study of two patients with Zimmermann-Laband syndrome and literature review.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Tabulation of clinical features confirmed the core phenotype and identified developmental delay as the unique major clinical problem (occurring in 40% of the cases) with a moderately high risk of epilepsy (13%)."
      explanation: Directly supports developmental delay as a clinical output, but does not establish the intervening neurodevelopmental mechanism.
  - target: Intellectual disability
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:33594261
      reference_title: "Syndromic disorders caused by gain-of-function variants in KCNH1, KCNK4, and KCNN3-a subgroup of K(+) channelopathies."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "There is notable overlap in the phenotypic findings of these syndromes associated with dominant KCNN3, KCNH1, and KCNK4 variants, sharing developmental delay and/or ID, coarse facial features, gingival enlargement, distal digital hypoplasia, and hypertrichosis."
      explanation: Directly names intellectual disability among the shared clinical outputs of the potassium-channel subtypes.
  - target: Seizure
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:23994350
      reference_title: Clinical and genetic study of two patients with Zimmermann-Laband syndrome and literature review.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Tabulation of clinical features confirmed the core phenotype and identified developmental delay as the unique major clinical problem (occurring in 40% of the cases) with a moderately high risk of epilepsy (13%)."
      explanation: Supports epilepsy as a clinical output in a minority of cases.
- name: Gingival and dental developmental overgrowth
  biological_scale: TISSUE
  description: >
    Gingival fibromatosis can cover tooth crowns and delay eruption, producing
    functional and aesthetic complications.
  role: downstream_pathology
  locations:
  - preferred_term: gingiva
    term: {id: UBERON:0001828, label: gingiva}
  evidence:
  - reference: PMID:40604848
    reference_title: "Syndromic gingival fibromatosis associated with pathogenic variation in the voltage-gated potassium channel gene KCNH1: a case report and proposed treatment protocol."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A common manifestation of these syndromes is gingival fibromatosis, which may partially or completely cover tooth crowns, leading in some cases to functional and aesthetic problems, as well as delayed tooth eruption."
    explanation: Links gingival fibromatosis to tooth coverage and delayed eruption.
  downstream:
  - target: Gingival fibromatosis
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:40604848
      reference_title: "Syndromic gingival fibromatosis associated with pathogenic variation in the voltage-gated potassium channel gene KCNH1: a case report and proposed treatment protocol."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "A common manifestation of these syndromes is gingival fibromatosis, which may partially or completely cover tooth crowns, leading in some cases to functional and aesthetic problems, as well as delayed tooth eruption."
      explanation: Directly supports the gingival-overgrowth phenotype.
  - target: Delayed eruption of teeth
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:40604848
      reference_title: "Syndromic gingival fibromatosis associated with pathogenic variation in the voltage-gated potassium channel gene KCNH1: a case report and proposed treatment protocol."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "A common manifestation of these syndromes is gingival fibromatosis, which may partially or completely cover tooth crowns, leading in some cases to functional and aesthetic problems, as well as delayed tooth eruption."
      explanation: Directly supports delayed eruption downstream of gingival coverage.
- name: Distal digital and nail developmental abnormality
  biological_scale: TISSUE
  description: >
    Hypoplasia or aplasia of nails and terminal phalanges is a core distal
    developmental feature of ZLS.
  role: downstream_pathology
  locations:
  - preferred_term: fingernail
    term: {id: UBERON:0009565, label: nail of manual digit}
  evidence:
  - reference: PMID:25915598
    reference_title: Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Zimmermann-Laband syndrome (ZLS) is a developmental disorder characterized by facial dysmorphism with gingival enlargement, intellectual disability, hypoplasia or aplasia of nails and terminal phalanges, and hypertrichosis."
    explanation: Identifies nail and terminal-phalanx abnormalities as core features.
  downstream:
  - target: Hypoplastic fingernail
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:25915598
      reference_title: Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Zimmermann-Laband syndrome (ZLS) is a developmental disorder characterized by facial dysmorphism with gingival enlargement, intellectual disability, hypoplasia or aplasia of nails and terminal phalanges, and hypertrichosis."
      explanation: Directly supports nail hypoplasia as a core manifestation.
  - target: Absent fingernail
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:25915598
      reference_title: Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Zimmermann-Laband syndrome (ZLS) is a developmental disorder characterized by facial dysmorphism with gingival enlargement, intellectual disability, hypoplasia or aplasia of nails and terminal phalanges, and hypertrichosis."
      explanation: Directly supports nail aplasia as a core manifestation.
  - target: Aplasia of distal finger phalanx
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:25915598
      reference_title: Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Zimmermann-Laband syndrome (ZLS) is a developmental disorder characterized by facial dysmorphism with gingival enlargement, intellectual disability, hypoplasia or aplasia of nails and terminal phalanges, and hypertrichosis."
      explanation: Directly supports terminal-phalanx aplasia as a core manifestation.
  - target: Short distal phalanx of finger
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:25915598
      reference_title: Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Zimmermann-Laband syndrome (ZLS) is a developmental disorder characterized by facial dysmorphism with gingival enlargement, intellectual disability, hypoplasia or aplasia of nails and terminal phalanges, and hypertrichosis."
      explanation: Supports hypoplastic or short terminal phalanges as a core manifestation.
mechanistic_hypotheses:
- hypothesis_group_id: ciliary_hedgehog_extraneurological
  hypothesis_label: Ciliary Kv10.1 and Hedgehog signaling explain extraneurological ZLS1 features
  status: EMERGING
  description: >
    Proposes that KCNH1-related gingival, nail, and distal digital anomalies
    arise from a non-excitable-cell role of Kv10.1 at the primary cilium. The
    cellular phenotype is demonstrated in fibroblast and RPE cultures, but the
    link to specific developing human tissues has not been shown.
  evidence:
  - reference: PMID:35639255
    reference_title: Potassium Channel KCNH1 Activating Variants Cause Altered Functional and Morphological Ciliogenesis.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "the pathogenic missense variants (L352V and R330Q; NP_002229.1) perturb cilia morphology, assembly/disassembly, and Sonic Hedgehog signaling, disclosing a multifaceted role of the protein"
    explanation: Provides the in-vitro basis for the emerging ciliary/Hedgehog model.
genetic:
- name: KCNH1 gain-of-function variants
  gene_term:
    preferred_term: KCNH1
    term:
      id: hgnc:6250
      label: KCNH1
  association: Causative
  subtype: ZLS1
  features: >
    Heterozygous KCNH1 missense variants account for a substantial proportion of
    molecularly solved ZLS and act through gain-of-function effects on the Eag1
    voltage-gated potassium channel.
  evidence:
  - reference: PMID:25915598
    reference_title: Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We report that heterozygous missense mutations in KCNH1 account for a considerable proportion of ZLS."
    explanation: The study identifies heterozygous KCNH1 missense variants as a common molecular cause.
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "KCNH1 | potassium voltage-gated channel subfamily H member 1 | hgnc:6250 | Disease-causing germline mutation(s) in"
    explanation: Orphanet lists KCNH1 as a disease-causing germline gene for ZLS.
- name: KCNN3 gain-of-function variants
  gene_term:
    preferred_term: KCNN3
    term:
      id: hgnc:6292
      label: KCNN3
  association: Causative
  subtype: ZLS3
  features: >
    De novo KCNN3 missense variants cause a typical ZLS phenotype through gain
    of function of the SK3 calcium-activated potassium channel.
  evidence:
  - reference: PMID:31155282
    reference_title: Gain-of-Function Mutations in KCNN3 Encoding the Small-Conductance Ca(2+)-Activated K(+) Channel SK3 Cause Zimmermann-Laband Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We report de novo missense variants in KCNN3 in three individuals with typical clinical features of ZLS."
    explanation: The study directly identifies de novo KCNN3 variants in individuals with typical ZLS.
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "KCNN3 | potassium calcium-activated channel subfamily N member 3 | hgnc:6292 | Disease-causing germline mutation(s) (gain of function) in"
    explanation: Orphanet lists gain-of-function KCNN3 disease-causing germline variants for ZLS.
- name: ATP6V1B2 missense variants
  gene_term:
    preferred_term: ATP6V1B2
    term:
      id: hgnc:854
      label: ATP6V1B2
  association: Causative
  subtype: ZLS2
  variant_origin: DE_NOVO
  features: >
    Recurrent de novo ATP6V1B2 missense variation contributes to ZLS2. The
    p.Arg485Pro substitution is among the tested dominant variants that produce
    gain of V-ATPase function and increased lysosomal acidification in
    patient-derived fibroblasts; its downstream cellular consequences are
    represented as separately evidenced pathophysiology nodes.
  variants:
  - name: ATP6V1B2 p.Arg485Pro
    description: >
      Recurrent heterozygous de novo missense substitution associated with ZLS2
      and directly characterized in primary patient fibroblasts.
    gene:
      preferred_term: ATP6V1B2
      term:
        id: hgnc:854
        label: ATP6V1B2
    type: missense
    clinical_significance: PATHOGENIC
    evidence:
    - reference: PMID:39210597
      reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "We investigated the functional consequences of the identified ATP6V1B2 and ATP6V1C1 variants, together with the p.Arg485Pro change in ATP6V1B2"
      explanation: Directly establishes inclusion of p.Arg485Pro in the functional series.
    - reference: PMID:39210597
      reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "Consistently, similar levels of endogenous ATP6V1B2 were also found in primary fibroblasts obtained from affected (B2A332V, B2Q376K, and B2R485P) and control individuals (Figure S3)."
      explanation: Directly identifies the p.Arg485Pro primary patient-fibroblast line.
  evidence:
  - reference: PMID:25915598
    reference_title: Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We also identified a recurrent de novo missense change in ATP6V1B2, encoding the B2 subunit of the multimeric vacuolar H(+) ATPase, in two individuals with ZLS."
    explanation: The study identifies recurrent de novo ATP6V1B2 variants in two ZLS individuals.
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "ATP6V1B2 | ATPase H+ transporting V1 subunit B2 | hgnc:854 | Disease-causing germline mutation(s) in"
    explanation: Orphanet lists ATP6V1B2 as a disease-causing germline gene for ZLS.
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "We observed a significant higher acidity of lysosomes in all patients’ cell lines compared with control cells, indicating a hyperactive behavior of the proton pumps assembling the mutant B2/C1 subunits."
    explanation: The tested patient lines, including p.Arg485Pro fibroblasts, showed hyperactive proton pumping and lysosomal hyperacidification.
phenotypes:
- category: Oral
  name: Gingival fibromatosis
  frequency: VERY_FREQUENT
  description: >
    Gingival fibromatosis is a hallmark oral feature but is not invariant across
    the molecular spectrum; it was absent in two KCNN3-related ZLS twins.
  phenotype_term:
    preferred_term: gingival fibromatosis
    term:
      id: HP:0000169
      label: Gingival fibromatosis
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000169 | Gingival fibromatosis | Obligate (100%)"
    explanation: >
      Orphanet supports the historical hallmark association, but its obligate
      frequency is not retained because later molecular cases lack the feature.
  - reference: PMID:34907639
    reference_title: Zimmermann-Laband syndrome in monozygotic twins with a mild neurobehavioral phenotype lacking gingival overgrowth-A case report of a novel KCNN3 gene variant.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Gingival overgrowth is absent in both individuals."
    explanation: Demonstrates that gingival overgrowth is not obligate in KCNN3-related ZLS.
- category: Craniofacial
  name: Wide mouth
  frequency: FREQUENT
  description: Wide mouth is a frequent craniofacial feature.
  phenotype_term:
    preferred_term: wide mouth
    term:
      id: HP:0000154
      label: Wide mouth
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000154 | Wide mouth | Frequent (79-30%)"
    explanation: Orphanet records wide mouth as frequent.
- category: Craniofacial
  name: Bulbous nose
  frequency: FREQUENT
  description: Bulbous nose is a frequent craniofacial feature.
  phenotype_term:
    preferred_term: bulbous nose
    term:
      id: HP:0000414
      label: Bulbous nose
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000414 | Bulbous nose | Frequent (79-30%)"
    explanation: Orphanet records bulbous nose as frequent.
- category: Craniofacial
  name: Wide nose
  frequency: FREQUENT
  description: Wide nose is a frequent craniofacial feature.
  phenotype_term:
    preferred_term: wide nose
    term:
      id: HP:0000445
      label: Wide nose
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000445 | Wide nose | Frequent (79-30%)"
    explanation: Orphanet records wide nose as frequent.
- category: Neurologic
  name: Global developmental delay
  frequency: FREQUENT
  description: >
    Developmental delay is a directly reported major clinical problem across
    the umbrella ZLS cohort; this umbrella claim is not restricted to one
    molecular subtype.
  phenotype_term:
    preferred_term: global developmental delay
    term:
      id: HP:0001263
      label: Global developmental delay
  evidence:
  - reference: PMID:23994350
    reference_title: Clinical and genetic study of two patients with Zimmermann-Laband syndrome and literature review.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Tabulation of clinical features confirmed the core phenotype and identified developmental delay as the unique major clinical problem (occurring in 40% of the cases) with a moderately high risk of epilepsy (13%)."
    explanation: Directly reports developmental delay in 40% of reviewed ZLS cases, supporting the FREQUENT band and the HPO term whose exact synonym includes developmental delay.
- category: Neurologic
  name: Intellectual disability
  frequency: FREQUENT
  description: Intellectual disability is a frequent neurodevelopmental feature.
  phenotype_term:
    preferred_term: intellectual disability
    term:
      id: HP:0001249
      label: Intellectual disability
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001249 | Intellectual disability | Frequent (79-30%)"
    explanation: Orphanet records intellectual disability as frequent.
  - reference: PMID:33594261
    reference_title: "Syndromic disorders caused by gain-of-function variants in KCNH1, KCNK4, and KCNN3-a subgroup of K(+) channelopathies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "There is notable overlap in the phenotypic findings of these syndromes associated with dominant KCNN3, KCNH1, and KCNK4 variants, sharing developmental delay and/or ID, coarse facial features, gingival enlargement, distal digital hypoplasia, and hypertrichosis."
    explanation: Directly names intellectual disability in the overlapping potassium-channel subtype phenotype; the FREQUENT band is independently supported by Orphanet.
- category: Musculoskeletal
  name: Joint hypermobility
  frequency: FREQUENT
  description: Joint hypermobility is a frequent musculoskeletal feature.
  phenotype_term:
    preferred_term: joint hypermobility
    term:
      id: HP:0001382
      label: Joint hypermobility
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001382 | Joint hypermobility | Frequent (79-30%)"
    explanation: Orphanet records joint hypermobility as frequent.
- category: Nail
  name: Hypoplastic fingernail
  frequency: FREQUENT
  description: Hypoplastic fingernails are a frequent distal digital feature.
  phenotype_term:
    preferred_term: hypoplastic fingernail
    term:
      id: HP:0001804
      label: Hypoplastic fingernail
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001804 | Hypoplastic fingernail | Frequent (79-30%)"
    explanation: Orphanet records hypoplastic fingernail as frequent.
- category: Nail
  name: Absent fingernail
  frequency: FREQUENT
  description: Absent fingernails are a frequent distal digital feature.
  phenotype_term:
    preferred_term: absent fingernail
    term:
      id: HP:0001817
      label: Absent fingernail
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001817 | Absent fingernail | Frequent (79-30%)"
    explanation: Orphanet records absent fingernail as frequent.
- category: Musculoskeletal
  name: Aplasia of distal finger phalanx
  description: Aplasia of terminal phalanges is a core distal digital feature.
  phenotype_term:
    preferred_term: aplasia of distal finger phalanx
    term:
      id: HP:0009881
      label: Aplasia of distal finger phalanx
  evidence:
  - reference: PMID:25915598
    reference_title: Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Zimmermann-Laband syndrome (ZLS) is a developmental disorder characterized by facial dysmorphism with gingival enlargement, intellectual disability, hypoplasia or aplasia of nails and terminal phalanges, and hypertrichosis."
    explanation: Supports distal-phalanx aplasia as part of the core ZLS phenotype.
- category: Musculoskeletal
  name: Short distal phalanx of finger
  description: Hypoplasia of terminal phalanges is a core distal digital feature.
  phenotype_term:
    preferred_term: hypoplastic distal finger phalanx
    term:
      id: HP:0009882
      label: Short distal phalanx of finger
  evidence:
  - reference: PMID:25915598
    reference_title: Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Zimmermann-Laband syndrome (ZLS) is a developmental disorder characterized by facial dysmorphism with gingival enlargement, intellectual disability, hypoplasia or aplasia of nails and terminal phalanges, and hypertrichosis."
    explanation: Supports terminal-phalanx hypoplasia as part of the core ZLS phenotype.
- category: Ear
  name: Large fleshy ears
  frequency: FREQUENT
  description: Large fleshy ears are a frequent craniofacial feature.
  phenotype_term:
    preferred_term: large fleshy ears
    term:
      id: HP:0002265
      label: Large fleshy ears
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002265 | Large fleshy ears | Frequent (79-30%)"
    explanation: Orphanet records large fleshy ears as frequent.
- category: Craniofacial
  name: Coarse facial features
  description: Coarse facial features are part of the characteristic ZLS gestalt.
  phenotype_term:
    preferred_term: coarse facial features
    term:
      id: HP:0000280
      label: Coarse facial features
  evidence:
  - reference: PMID:33594261
    reference_title: "Syndromic disorders caused by gain-of-function variants in KCNH1, KCNK4, and KCNN3-a subgroup of K(+) channelopathies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "There is notable overlap in the phenotypic findings of these syndromes associated with dominant KCNN3, KCNH1, and KCNK4 variants, sharing developmental delay and/or ID, coarse facial features, gingival enlargement, distal digital hypoplasia, and hypertrichosis."
    explanation: Identifies coarse facial features as part of the overlapping syndromic potassium-channelopathy phenotype.
- category: Hair
  name: Generalized hypertrichosis
  frequency: FREQUENT
  description: Generalized hypertrichosis is a frequent hair phenotype.
  phenotype_term:
    preferred_term: generalized hypertrichosis
    term:
      id: HP:0004554
      label: Generalized hypertrichosis
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0004554 | Generalized hypertrichosis | Frequent (79-30%)"
    explanation: Orphanet records generalized hypertrichosis as frequent.
- category: Oral
  name: Anterior open-bite malocclusion
  frequency: FREQUENT
  description: Anterior open-bite malocclusion is a frequent oral/dental feature.
  phenotype_term:
    preferred_term: anterior open-bite malocclusion
    term:
      id: HP:0009102
      label: Anterior open-bite malocclusion
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0009102 | Anterior open-bite malocclusion | Frequent (79-30%)"
    explanation: Orphanet records anterior open-bite malocclusion as frequent.
- category: Ear
  name: Thickened ears
  frequency: FREQUENT
  description: Thickened ears are a frequent craniofacial feature.
  phenotype_term:
    preferred_term: thickened ears
    term:
      id: HP:0009894
      label: Thickened ears
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0009894 | Thickened ears | Frequent (79-30%)"
    explanation: Orphanet records thickened ears as frequent.
- category: Oral
  name: Macroglossia
  frequency: OCCASIONAL
  description: Macroglossia is an occasional oral feature.
  phenotype_term:
    preferred_term: macroglossia
    term:
      id: HP:0000158
      label: Macroglossia
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000158 | Macroglossia | Occasional (29-5%)"
    explanation: Orphanet records macroglossia as occasional.
- category: Oral
  name: Cleft palate
  frequency: OCCASIONAL
  description: Cleft palate is an occasional palatal feature.
  phenotype_term:
    preferred_term: cleft palate
    term:
      id: HP:0000175
      label: Cleft palate
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000175 | Cleft palate | Occasional (29-5%)"
    explanation: Orphanet records cleft palate as occasional.
- category: Oral
  name: Bifid uvula
  frequency: OCCASIONAL
  description: Bifid uvula is an occasional palatal feature.
  phenotype_term:
    preferred_term: bifid uvula
    term:
      id: HP:0000193
      label: Bifid uvula
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000193 | Bifid uvula | Occasional (29-5%)"
    explanation: Orphanet records bifid uvula as occasional.
- category: Oral
  name: High palate
  frequency: OCCASIONAL
  description: High palate is an occasional palatal feature.
  phenotype_term:
    preferred_term: high palate
    term:
      id: HP:0000218
      label: High palate
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000218 | High palate | Occasional (29-5%)"
    explanation: Orphanet records high palate as occasional.
- category: Craniofacial
  name: Hypertelorism
  frequency: OCCASIONAL
  description: Hypertelorism is an occasional craniofacial feature.
  phenotype_term:
    preferred_term: hypertelorism
    term:
      id: HP:0000316
      label: Hypertelorism
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000316 | Hypertelorism | Occasional (29-5%)"
    explanation: Orphanet records hypertelorism as occasional.
- category: Craniofacial
  name: Micrognathia
  frequency: OCCASIONAL
  description: Micrognathia is an occasional jaw feature.
  phenotype_term:
    preferred_term: micrognathia
    term:
      id: HP:0000347
      label: Micrognathia
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000347 | Micrognathia | Occasional (29-5%)"
    explanation: Orphanet records micrognathia as occasional.
- category: Craniofacial
  name: Short neck
  frequency: OCCASIONAL
  description: Short neck is an occasional craniofacial feature.
  phenotype_term:
    preferred_term: short neck
    term:
      id: HP:0000470
      label: Short neck
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000470 | Short neck | Occasional (29-5%)"
    explanation: Orphanet records short neck as occasional.
- category: Ocular
  name: Downslanted palpebral fissures
  frequency: OCCASIONAL
  description: Downslanted palpebral fissures are occasional ocular-adnexal features.
  phenotype_term:
    preferred_term: downslanted palpebral fissures
    term:
      id: HP:0000494
      label: Downslanted palpebral fissures
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000494 | Downslanted palpebral fissures | Occasional (29-5%)"
    explanation: Orphanet records downslanted palpebral fissures as occasional.
- category: Ocular
  name: Telecanthus
  frequency: OCCASIONAL
  description: Telecanthus is an occasional ocular-adnexal feature.
  phenotype_term:
    preferred_term: telecanthus
    term:
      id: HP:0000506
      label: Telecanthus
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000506 | Telecanthus | Occasional (29-5%)"
    explanation: Orphanet records telecanthus as occasional.
- category: Ocular
  name: Cataract
  frequency: OCCASIONAL
  description: Cataract is an occasional ocular feature.
  phenotype_term:
    preferred_term: cataract
    term:
      id: HP:0000518
      label: Cataract
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000518 | Cataract | Occasional (29-5%)"
    explanation: Orphanet records cataract as occasional.
- category: Craniofacial
  name: Long eyelashes
  frequency: OCCASIONAL
  description: Long eyelashes are an occasional craniofacial hair feature.
  phenotype_term:
    preferred_term: long eyelashes
    term:
      id: HP:0000527
      label: Long eyelashes
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000527 | Long eyelashes | Occasional (29-5%)"
    explanation: Orphanet records long eyelashes as occasional.
- category: Craniofacial
  name: Thick eyebrow
  frequency: OCCASIONAL
  description: Thick eyebrow is an occasional craniofacial hair feature.
  phenotype_term:
    preferred_term: thick eyebrow
    term:
      id: HP:0000574
      label: Thick eyebrow
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000574 | Thick eyebrow | Occasional (29-5%)"
    explanation: Orphanet records thick eyebrow as occasional.
- category: Oral
  name: Hypodontia
  frequency: OCCASIONAL
  description: Hypodontia is an occasional dental feature.
  phenotype_term:
    preferred_term: hypodontia
    term:
      id: HP:0000668
      label: Hypodontia
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000668 | Hypodontia | Occasional (29-5%)"
    explanation: Orphanet records hypodontia as occasional.
- category: Genitourinary
  name: Abnormal external genitalia
  frequency: OCCASIONAL
  description: Abnormal external genitalia are reported occasionally.
  phenotype_term:
    preferred_term: abnormal external genitalia
    term:
      id: HP:0000811
      label: Abnormal external genitalia morphology
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000811 | Abnormal external genitalia | Occasional (29-5%)"
    explanation: Orphanet records abnormal external genitalia as occasional.
- category: Dermatologic
  name: Soft skin
  frequency: OCCASIONAL
  description: Soft skin is reported occasionally.
  phenotype_term:
    preferred_term: soft skin
    term:
      id: HP:0000977
      label: Soft skin
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000977 | Soft skin | Occasional (29-5%)"
    explanation: Orphanet records soft skin as occasional.
- category: Neurologic
  name: Seizure
  frequency: OCCASIONAL
  description: Seizures are an occasional neurologic feature.
  phenotype_term:
    preferred_term: seizure
    term:
      id: HP:0001250
      label: Seizure
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001250 | Seizure | Occasional (29-5%)"
    explanation: Orphanet records seizure as occasional.
  - reference: PMID:23994350
    reference_title: Clinical and genetic study of two patients with Zimmermann-Laband syndrome and literature review.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Tabulation of clinical features confirmed the core phenotype and identified developmental delay as the unique major clinical problem (occurring in 40% of the cases) with a moderately high risk of epilepsy (13%)."
    explanation: Literature review reports epilepsy in 13% of reviewed cases, consistent with occasional frequency.
- category: Growth
  name: Growth delay
  frequency: OCCASIONAL
  description: Growth delay is reported occasionally.
  phenotype_term:
    preferred_term: growth delay
    term:
      id: HP:0001510
      label: Growth delay
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001510 | Growth delay | Occasional (29-5%)"
    explanation: Orphanet records growth delay as occasional.
- category: Abdominal
  name: Splenomegaly
  frequency: OCCASIONAL
  description: Splenomegaly is reported occasionally.
  phenotype_term:
    preferred_term: splenomegaly
    term:
      id: HP:0001744
      label: Splenomegaly
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001744 | Splenomegaly | Occasional (29-5%)"
    explanation: Orphanet records splenomegaly as occasional.
- category: Musculoskeletal
  name: Pes cavus
  frequency: OCCASIONAL
  description: Pes cavus is reported occasionally.
  phenotype_term:
    preferred_term: pes cavus
    term:
      id: HP:0001761
      label: Pes cavus
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001761 | Pes cavus | Occasional (29-5%)"
    explanation: Orphanet records pes cavus as occasional.
- category: Musculoskeletal
  name: Pes planus
  frequency: OCCASIONAL
  description: Pes planus is reported occasionally.
  phenotype_term:
    preferred_term: pes planus
    term:
      id: HP:0001763
      label: Pes planus
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001763 | Pes planus | Occasional (29-5%)"
    explanation: Orphanet records pes planus as occasional.
- category: Musculoskeletal
  name: Hallux valgus
  frequency: OCCASIONAL
  description: Hallux valgus is reported occasionally.
  phenotype_term:
    preferred_term: hallux valgus
    term:
      id: HP:0001822
      label: Hallux valgus
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001822 | Hallux valgus | Occasional (29-5%)"
    explanation: Orphanet records hallux valgus as occasional.
- category: Hair
  name: Facial hypertrichosis
  frequency: OCCASIONAL
  description: Facial hypertrichosis is reported occasionally.
  phenotype_term:
    preferred_term: facial hypertrichosis
    term:
      id: HP:0002219
      label: Facial hypertrichosis
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002219 | Facial hypertrichosis | Occasional (29-5%)"
    explanation: Orphanet records facial hypertrichosis as occasional.
- category: Abdominal
  name: Hepatomegaly
  frequency: OCCASIONAL
  description: Hepatomegaly is reported occasionally.
  phenotype_term:
    preferred_term: hepatomegaly
    term:
      id: HP:0002240
      label: Hepatomegaly
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002240 | Hepatomegaly | Occasional (29-5%)"
    explanation: Orphanet records hepatomegaly as occasional.
- category: Neurologic
  name: Floppy infant
  frequency: OCCASIONAL
  description: Floppy infant is reported occasionally.
  phenotype_term:
    preferred_term: floppy infant
    term:
      id: HP:0008947
      label: Floppy infant
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0008947 | Floppy infant | Occasional (29-5%)"
    explanation: Orphanet records floppy infant as occasional.
- category: Oral
  name: Supernumerary tooth
  frequency: OCCASIONAL
  description: Supernumerary teeth are reported occasionally.
  phenotype_term:
    preferred_term: supernumerary tooth
    term:
      id: HP:0011069
      label: Supernumerary tooth
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0011069 | Supernumerary tooth | Occasional (29-5%)"
    explanation: Orphanet records supernumerary tooth as occasional.
- category: Cardiovascular
  name: Abnormal cardiovascular system morphology
  frequency: OCCASIONAL
  description: Cardiovascular structural abnormalities are reported occasionally.
  phenotype_term:
    preferred_term: abnormal cardiovascular system morphology
    term:
      id: HP:0030680
      label: Abnormal cardiovascular system morphology
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0030680 | Abnormal cardiovascular system morphology | Occasional (29-5%)"
    explanation: Orphanet records abnormal cardiovascular system morphology as occasional.
- category: Oral
  name: Delayed eruption of teeth
  frequency: OCCASIONAL
  description: Gingival fibromatosis may cover crowns and delay tooth eruption.
  phenotype_term:
    preferred_term: delayed eruption of teeth
    term:
      id: HP:0000684
      label: Delayed eruption of teeth
  evidence:
  - reference: PMID:40604848
    reference_title: "Syndromic gingival fibromatosis associated with pathogenic variation in the voltage-gated potassium channel gene KCNH1: a case report and proposed treatment protocol."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A common manifestation of these syndromes is gingival fibromatosis, which may partially or completely cover tooth crowns, leading in some cases to functional and aesthetic problems, as well as delayed tooth eruption."
    explanation: The case report and protocol supports delayed tooth eruption as a complication of gingival fibromatosis.
- category: Auditory
  name: Sensorineural hearing impairment
  frequency: VERY_RARE
  description: Sensorineural hearing impairment is reported very rarely.
  phenotype_term:
    preferred_term: sensorineural hearing impairment
    term:
      id: HP:0000407
      label: Sensorineural hearing impairment
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000407 | Sensorineural hearing impairment | Very rare (<4-1%)"
    explanation: Orphanet records sensorineural hearing impairment as very rare.
- category: Musculoskeletal
  name: Deep plantar creases
  frequency: VERY_RARE
  description: Deep plantar creases are reported very rarely.
  phenotype_term:
    preferred_term: deep plantar creases
    term:
      id: HP:0001869
      label: Deep plantar creases
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001869 | Deep plantar creases | Very rare (<4-1%)"
    explanation: Orphanet records deep plantar creases as very rare.
- category: Musculoskeletal
  name: Deep palmar crease
  frequency: VERY_RARE
  description: Deep palmar crease is reported very rarely.
  phenotype_term:
    preferred_term: deep palmar crease
    term:
      id: HP:0006191
      label: Deep palmar crease
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0006191 | Deep palmar crease | Very rare (<4-1%)"
    explanation: Orphanet records deep palmar crease as very rare.
- category: Skeletal
  name: Overtubulated long bones
  frequency: VERY_RARE
  description: Overtubulated long bones are reported very rarely.
  phenotype_term:
    preferred_term: overtubulated long bones
    term:
      id: HP:0006391
      label: Overtubulated long bones
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0006391 | Overtubulated long bones | Very rare (<4-1%)"
    explanation: Orphanet records overtubulated long bones as very rare.
- category: Dermatologic
  name: Generalized hyperpigmentation
  frequency: VERY_RARE
  description: Generalized hyperpigmentation is reported very rarely.
  phenotype_term:
    preferred_term: generalized hyperpigmentation
    term:
      id: HP:0007440
      label: Generalized hyperpigmentation
  evidence:
  - reference: ORPHA:3473
    reference_title: "Zimmermann-Laband syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0007440 | Generalized hyperpigmentation | Very rare (<4-1%)"
    explanation: Orphanet records generalized hyperpigmentation as very rare.
diagnosis:
- name: Clinical syndrome recognition
  description: >
    Clinical recognition is based on the combination of gingival fibromatosis,
    coarse facial appearance, hypertrichosis, neurodevelopmental involvement,
    and distal nail or phalangeal abnormalities.
  diagnosis_term:
    preferred_term: examination by clinical professional
    term:
      id: NCIT:C20989
      label: Physical Examination
  evidence:
  - reference: PMID:25915598
    reference_title: Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Zimmermann-Laband syndrome (ZLS) is a developmental disorder characterized by facial dysmorphism with gingival enlargement, intellectual disability, hypoplasia or aplasia of nails and terminal phalanges, and hypertrichosis."
    explanation: The molecular genetics paper summarizes the core clinical-recognition pattern.
- name: Molecular genetic testing
  description: >
    Sequencing can identify pathogenic variants in KCNH1, KCNN3, or ATP6V1B2
    and distinguish ZLS from overlapping potassium-channel dysmorphism syndromes.
  diagnosis_term:
    preferred_term: genetic testing
    term:
      id: NCIT:C15709
      label: Genetic Testing
  evidence:
  - reference: PMID:39087232
    reference_title: "Clinical and genetic evaluations of Zimmermann-Laband syndrome with gingival fibromatosis: a rare case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A novel pathogenic variant in the KCNH1 gene was identified using whole-exome sequencing to substantiate our preliminary diagnosis."
    explanation: Whole-exome sequencing confirmed a KCNH1 pathogenic variant after clinical suspicion of ZLS.
  - reference: PMID:25915598
    reference_title: Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We also identified a recurrent de novo missense change in ATP6V1B2, encoding the B2 subunit of the multimeric vacuolar H(+) ATPase, in two individuals with ZLS."
    explanation: Supports ATP6V1B2 testing in molecular confirmation of ZLS2.
  - reference: PMID:31155282
    reference_title: Gain-of-Function Mutations in KCNN3 Encoding the Small-Conductance Ca(2+)-Activated K(+) Channel SK3 Cause Zimmermann-Laband Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We report de novo missense variants in KCNN3 in three individuals with typical clinical features of ZLS."
    explanation: Supports KCNN3 testing in molecular confirmation of ZLS3.
differential_diagnoses:
- name: Temple-Baraitser syndrome
  description: >
    Temple-Baraitser syndrome and ZLS1 share KCNH1 gain-of-function variants,
    intellectual disability, epilepsy, facial dysmorphism, and nail anomalies.
    Gingival enlargement and hypertrichosis favor the ZLS gestalt, whereas
    broad thumbs and great toes with absent or hypoplastic nails favor TBS;
    phenotype overlap can make molecular results more informative than labels.
  disease_term:
    preferred_term: Temple-Baraitser syndrome
    term:
      id: MONDO:0012735
      label: Temple-Baraitser syndrome
  distinguishing_features:
  - Gingival enlargement and hypertrichosis favor Zimmermann-Laband syndrome.
  - Broad thumbs and great toes with absent or hypoplastic nails favor Temple-Baraitser syndrome.
  - KCNH1-related phenotypes overlap and may not satisfy either classic gestalt.
  evidence:
  - reference: PMID:26264464
    reference_title: "'Splitting versus lumping': Temple-Baraitser and Zimmermann-Laband Syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "TMBTS is characterized by intellectual disability (ID), epilepsy, dysmorphic facial features, broad thumbs and great toes with absent/hypoplastic nails. ZLS is characterized by facial dysmorphism including coarsening of the face and a large nose, gingival enlargement, ID, hypoplasia of terminal phalanges and nails and hypertrichosis."
    explanation: States the overlapping and distinguishing clinical features of TBS and ZLS.
- name: KCNK4-related FHEIG syndrome
  description: >
    KCNK4 gain-of-function disease overlaps ZLS through facial dysmorphism,
    hypertrichosis, epilepsy, intellectual disability, and gingival overgrowth.
    Molecular testing distinguishes KCNK4-related FHEIG from the three ZLS
    molecular subtypes.
  disease_term:
    preferred_term: facial dysmorphism, hypertrichosis, epilepsy, intellectual/developmental delay, and gingival overgrowth syndrome
    term:
      id: MONDO:0032714
      label: facial dysmorphism, hypertrichosis, epilepsy, intellectual/developmental delay, and gingival overgrowth syndrome
  distinguishing_features:
  - A pathogenic KCNK4 variant supports FHEIG rather than ZLS1, ZLS2, or ZLS3.
  evidence:
  - reference: PMID:33594261
    reference_title: "Syndromic disorders caused by gain-of-function variants in KCNH1, KCNK4, and KCNN3-a subgroup of K(+) channelopathies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We suggest to combine the phenotypes and define a new subgroup of potassium channelopathies caused by increased K+ conductance, referred to as syndromic neurodevelopmental K+ channelopathies due to dominant variants in KCNH1, KCNK4, or KCNN3."
    explanation: Establishes KCNK4 disease as a close syndromic potassium-channelopathy mimic.
- name: Dominant deafness-onychodystrophy syndrome
  description: >
    ATP6V1B2-associated dominant deafness-onychodystrophy (DDOD) syndrome is an
    allelic differential within the same dominant V-ATPase clinical continuum.
    Sensorineural deafness and onychodystrophy with digital anomalies
    predominate in DDOD, whereas gingival hypertrophy and hypertrichosis are
    more characteristic of ZLS2.
  disease_term:
    preferred_term: autosomal dominant deafness - onychodystrophy syndrome
    term:
      id: MONDO:0007420
      label: autosomal dominant deafness - onychodystrophy syndrome
  distinguishing_features:
  - Predominant sensorineural deafness, onychodystrophy, and characteristic digital anomalies favor DDOD.
  - Gingival hypertrophy and hypertrichosis favor ZLS2 because they are not usually reported in DDOD or DOORS.
  - ATP6V1B2 genotype and the broader phenotype should be interpreted as a continuum rather than as an absolute boundary.
  evidence:
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Specifically, individuals with DDOD syndrome primarily share sensorineural deafness and onychodystrophy with digital anomalies characterized by bulbous fingertips of digits, and finger-like thumbs/triphalangeal thumb."
    explanation: Directly states the predominant DDOD distinguishing features.
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Facial features of DOORS syndrome have a significant overlap with ZLS, a condition also associated with organomegaly, gingival hypertrophy, and hypertrichosis, which are not usually reported in DDOD and DOORS syndromes."
    explanation: Supports gingival hypertrophy and hypertrichosis, but not coarse facies, as ZLS-favoring distinctions.
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The present findings further support these observations, documenting the presence of a phenotypic continuum among these disorders."
    explanation: Supports interpreting DDOD and ZLS2 as a clinical continuum rather than an absolute boundary.
- name: DOORS syndrome
  description: >
    DOORS syndrome overlaps ATP6V1B2-related ZLS2 through deafness, nail and
    distal-phalangeal abnormalities, neurodevelopmental impairment, and
    seizures. Osteodystrophy and the deafness-onychodystrophy-neurologic
    constellation favor DOORS, while gingival hypertrophy and hypertrichosis
    favor ZLS2. The cited ATP6V1B2 study places these presentations on a
    clinically variable continuum.
  disease_term:
    preferred_term: DOORS syndrome
    term:
      id: MONDO:0009079
      label: DOORS syndrome
  distinguishing_features:
  - Sensorineural hearing loss, onychodystrophy, distal digital abnormalities, osteodystrophy, and seizures favor DOORS syndrome.
  - Gingival hypertrophy and hypertrichosis favor ZLS2 because they are not usually reported in DDOD or DOORS.
  - The broader phenotype should be interpreted as a continuum rather than as an absolute boundary.
  evidence:
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "DOORS syndrome shares sensorineural hearing loss, onychodystrophy, and digital abnormalities (i.e., triphalangeal thumb and hypoplastic/absent distal phalanges) with DDOD syndrome."
    explanation: Directly states the shared DOORS distinguishing features.
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Osteodystrophy is reported in most cases as well as a neurodevelopmental/neurological involvement, which includes seizures."
    explanation: Directly supports osteodystrophy and seizures as DOORS-favoring features.
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Facial features of DOORS syndrome have a significant overlap with ZLS, a condition also associated with organomegaly, gingival hypertrophy, and hypertrichosis, which are not usually reported in DDOD and DOORS syndromes."
    explanation: Supports gingival hypertrophy and hypertrichosis, but not coarse facies, as ZLS-favoring distinctions.
  - reference: PMID:39210597
    reference_title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The present findings further support these observations, documenting the presence of a phenotypic continuum among these disorders."
    explanation: Supports treating DOORS-like and ZLS2 presentations as a variable continuum.
treatments:
- name: Gingivectomy and gingivoplasty for gingival fibromatosis
  description: >
    Surgical removal and reshaping of hyperplastic gingiva can expose teeth,
    improve occlusion, restore dental function, and improve oral aesthetics.
  therapeutic_modality: SURGERY
  treatment_term:
    preferred_term: gingivectomy
    term:
      id: NCIT:C82090
      label: Gingivectomy
  target_phenotypes:
  - preferred_term: gingival fibromatosis
    term:
      id: HP:0000169
      label: Gingival fibromatosis
  - preferred_term: delayed eruption of teeth
    term:
      id: HP:0000684
      label: Delayed eruption of teeth
  evidence:
  - reference: PMID:39087232
    reference_title: "Clinical and genetic evaluations of Zimmermann-Laband syndrome with gingival fibromatosis: a rare case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Gingivectomy and gingivoplasty were performed under general anesthesia. After surgery, the gingival appearance improved significantly, and the masticatory function of the teeth was restored."
    explanation: A ZLS case report documents functional improvement after gingivectomy and gingivoplasty.
  - reference: PMID:40604848
    reference_title: "Syndromic gingival fibromatosis associated with pathogenic variation in the voltage-gated potassium channel gene KCNH1: a case report and proposed treatment protocol."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "This case illustrates the need for appropriate and early gingivoplasty to prevent teeth impaction and restore dental function."
    explanation: The proposed protocol supports early gingivoplasty for gingival fibromatosis-associated tooth impaction and dental dysfunction.
  - reference: PMID:40425216
    reference_title: Surgical management of hereditary gingival fibromatosis associated with Zimmermann-Laband syndrome using conventional, electrocautery and diode laser gingivectomy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In this case report, the surgical management of HGF associated with the Zimmermann-Laband syndrome was successfully carried out using three different methods: conventional gingivectomy, electrocautery and diode laser gingivectomy."
    explanation: Independently documents successful gingivectomy approaches in ZLS-associated gingival fibromatosis.
- name: Myofunctional and speech-language oral therapy
  description: >
    Myofunctional and speech-language therapy may support biting, chewing, and
    tongue-function rehabilitation before or alongside gingivoplasty.
  therapeutic_modality: BEHAVIORAL
  treatment_term:
    preferred_term: speech language therapy
    term:
      id: NCIT:C159273
      label: Speech Language Therapy
  evidence:
  - reference: PMID:40604848
    reference_title: "Syndromic gingival fibromatosis associated with pathogenic variation in the voltage-gated potassium channel gene KCNH1: a case report and proposed treatment protocol."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The first step of oral treatment consisted of myofunctional and speech/language therapy to stimulate biting and chewing. It also helped with the rehabilitation of proper tongue function."
    explanation: The case protocol supports supportive oral therapy to improve biting, chewing, and tongue function.
notes: >
  Orphanet records autosomal recessive inheritance, but molecular literature
  supports de novo or autosomal-dominant inheritance for KCNH1 and KCNN3-related
  disease. This entry follows the molecularly solved, dominant potassium-channel
  and ATP6V1B2 genetic heterogeneity while retaining the ORPHA structured record
  for phenotype coverage. Temple-Baraitser syndrome and KCNK4-related FHEIG
  syndrome overlap clinically with ZLS and may be considered in differential
  diagnosis.
references:
- reference: ORPHA:3473
  title: Zimmermann-Laband syndrome
  found_in:
  - Zimmermann_Laband_Syndrome-deep-research-fallback.md
  findings: []
- reference: PMID:23994350
  title: Clinical and genetic study of two patients with Zimmermann-Laband syndrome and literature review.
  found_in:
  - Zimmermann_Laband_Syndrome-deep-research-fallback.md
  findings: []
- reference: PMID:26264464
  title: "'Splitting versus lumping': Temple-Baraitser and Zimmermann-Laband Syndromes."
  findings: []
- reference: PMID:25915598
  title: Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome.
  found_in:
  - Zimmermann_Laband_Syndrome-deep-research-fallback.md
  findings: []
- reference: PMID:31155282
  title: Gain-of-Function Mutations in KCNN3 Encoding the Small-Conductance Ca(2+)-Activated K(+) Channel SK3 Cause Zimmermann-Laband Syndrome.
  found_in:
  - Zimmermann_Laband_Syndrome-deep-research-fallback.md
  findings: []
- reference: PMID:33594261
  title: "Syndromic disorders caused by gain-of-function variants in KCNH1, KCNK4, and KCNN3-a subgroup of K(+) channelopathies."
  found_in:
  - Zimmermann_Laband_Syndrome-deep-research-fallback.md
  findings: []
- reference: PMID:34907639
  title: Zimmermann-Laband syndrome in monozygotic twins with a mild neurobehavioral phenotype lacking gingival overgrowth-A case report of a novel KCNN3 gene variant.
  findings: []
- reference: PMID:35639255
  title: Potassium Channel KCNH1 Activating Variants Cause Altered Functional and Morphological Ciliogenesis.
  found_in:
  - Zimmermann_Laband_Syndrome-deep-research-fallback.md
  findings: []
- reference: PMID:39087232
  title: "Clinical and genetic evaluations of Zimmermann-Laband syndrome with gingival fibromatosis: a rare case report."
  found_in:
  - Zimmermann_Laband_Syndrome-deep-research-fallback.md
  findings: []
- reference: PMID:39210597
  title: Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
  findings: []
- reference: PMID:40425216
  title: Surgical management of hereditary gingival fibromatosis associated with Zimmermann-Laband syndrome using conventional, electrocautery and diode laser gingivectomy.
  findings: []
- reference: PMID:40604848
  title: "Syndromic gingival fibromatosis associated with pathogenic variation in the voltage-gated potassium channel gene KCNH1: a case report and proposed treatment protocol."
  found_in:
  - Zimmermann_Laband_Syndrome-deep-research-fallback.md
  findings: []
📚

References & Deep Research

References

12
ORPHA:3473
Zimmermann-Laband syndrome
No top-level findings curated for this source.
PMID:23994350
Clinical and genetic study of two patients with Zimmermann-Laband syndrome and literature review.
No top-level findings curated for this source.
PMID:26264464
'Splitting versus lumping': Temple-Baraitser and Zimmermann-Laband Syndromes.
No top-level findings curated for this source.
PMID:25915598
Mutations in KCNH1 and ATP6V1B2 cause Zimmermann-Laband syndrome.
No top-level findings curated for this source.
PMID:31155282
Gain-of-Function Mutations in KCNN3 Encoding the Small-Conductance Ca(2+)-Activated K(+) Channel SK3 Cause Zimmermann-Laband Syndrome.
No top-level findings curated for this source.
PMID:33594261
Syndromic disorders caused by gain-of-function variants in KCNH1, KCNK4, and KCNN3-a subgroup of K(+) channelopathies.
No top-level findings curated for this source.
PMID:34907639
Zimmermann-Laband syndrome in monozygotic twins with a mild neurobehavioral phenotype lacking gingival overgrowth-A case report of a novel KCNN3 gene variant.
No top-level findings curated for this source.
PMID:35639255
Potassium Channel KCNH1 Activating Variants Cause Altered Functional and Morphological Ciliogenesis.
No top-level findings curated for this source.
PMID:39087232
Clinical and genetic evaluations of Zimmermann-Laband syndrome with gingival fibromatosis: a rare case report.
No top-level findings curated for this source.
PMID:39210597
Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.
No top-level findings curated for this source.
PMID:40425216
Surgical management of hereditary gingival fibromatosis associated with Zimmermann-Laband syndrome using conventional, electrocautery and diode laser gingivectomy.
No top-level findings curated for this source.
PMID:40604848
Syndromic gingival fibromatosis associated with pathogenic variation in the voltage-gated potassium channel gene KCNH1: a case report and proposed treatment protocol.
No top-level findings curated for this source.

Deep Research

1
Zimmermann-Laband Syndrome Deep-Research Fallback ▸

Zimmermann-Laband Syndrome Deep-Research Fallback

An automated deep-research provider was attempted after the initial cache-backed YAML existed, but it stayed silent and was stopped by the bounded timeout:

  • timeout 120s just research-disorder openai Zimmermann_Laband_Syndrome returned 124.

The curation therefore used generated local caches plus direct PubMed searches and fetched PubMed/Orphanet records. The reviewed disease scope is Zimmermann-Laband syndrome as represented by ORPHA:3473 and MONDO:0000200, including the molecularly solved KCNH1, KCNN3, and ATP6V1B2 genetic heterogeneity.

Scope Confirmation

  • ORPHA:3473 supplied the definition, neonatal onset, cross-references, gene-disease rows, epidemiology, and all HPO phenotype rows.
  • PMID:23994350 supplied the clinical literature review, developmental-delay and epilepsy frequencies, and inheritance interpretation.
  • PMID:25915598 supplied the KCNH1 gain-of-function mechanism, ATP6V1B2 recurrent de novo variation, and the core clinical feature summary.
  • PMID:31155282 supplied KCNN3 de novo variants and patch-clamp gain-of-function evidence.
  • PMID:33594261 supplied the broader syndromic neurodevelopmental potassium channelopathy framing for KCNH1/KCNN3-related disease.
  • PMID:35639255 supplied KCNH1 ciliary localization and ciliogenesis/Sonic Hedgehog signaling perturbation evidence.
  • PMID:39087232 and PMID:40604848 supplied oral-management evidence for gingival fibromatosis, delayed tooth eruption, gingivectomy, gingivoplasty, and supportive myofunctional/speech-language oral therapy.

Coverage Notes

The YAML intentionally models the most evidence-backed mechanisms as a compact pathograph: increased K+ conductance, ATP6V1B2 V-ATPase complex perturbation, KCNH1-related ciliary signaling disruption, neurodevelopmental dysfunction, gingival/dental overgrowth, and distal digital/nail developmental abnormality. Temple-Baraitser syndrome and KCNK4-related FHEIG overlap clinically, but they are kept as differential/overlap notes rather than merged into the ZLS disease entry.