X-linked hydrocephalus syndrome: genes and variants
X-linked hydrocephalus syndrome is linked to 1 analyzed protein (L1CAM). 8 DNA variants are known to cause it; 16 more are uncertain, and 0 of those already look disease-causing on computable evidence.
Last updated 2026-09-30. Research information, not medical advice.
Genes linked to X-linked hydrocephalus syndrome
L1CAM: Neural cell adhesion molecule L1
It promotes neuronal adhesion, axon guidance, neurite growth, and fasciculation during nervous-system development. Loss-of-function variants cause L1 syndrome, encompassing X-linked hydrocephalus, MASA syndrome, spastic paraplegia, and variable intellectual disability.
8 disease-causing and 15 uncertain variants in L1CAM are linked to X-linked hydrocephalus syndrome.
Weakly linked (only a few uncertain records): TUBB3.
Where X-linked hydrocephalus syndrome variants cluster
- L1CAM Fibronectin type-III 2 (positions 717–810): 3 of 8 disease-causing changes, 5.0× more than its size predicts.
Known disease-causing variants in X-linked hydrocephalus syndrome
| Variant | Position | Protein part | Clinical label |
|---|---|---|---|
| L1CAM G411W | 411 | Ig-like C2-type 4 | Disease-causing (★) |
| L1CAM Y784C | 784 | Fibronectin type-III 2 | Disease-causing (★) |
| L1CAM P800H | 800 | Fibronectin type-III 2 | Disease-causing (★) |
| L1CAM M1I | 1 | Disease-causing (★) | |
| L1CAM D202G | 202 | Ig-like C2-type 2 | Disease-causing (★) |
| L1CAM C264Y | 264 | Ig-like C2-type 3 | Disease-causing |
| L1CAM C539G | 539 | Ig-like C2-type 6 | Disease-causing |
| L1CAM N792K | 792 | Fibronectin type-III 2 | Disease-causing |
Same protein, different disease
- L1 syndrome is also caused by L1CAM variants; they fall mostly in different places as the X-linked hydrocephalus syndrome variants (7 disease-causing).
- MASA syndrome is also caused by L1CAM variants; they fall mostly in different places as the X-linked hydrocephalus syndrome variants (6 disease-causing).
Diseases related to X-linked hydrocephalus syndrome
- L1 syndrome, also linked to L1CAM
- Muscular dystrophy, limb-girdle, autosomal recessive 23, also linked to L1CAM
- MASA syndrome, also linked to L1CAM
- Hydrops fetalis, also linked to L1CAM
- X-linked complicated corpus callosum dysgenesis, also linked to L1CAM
Frequently asked questions
Which genes are linked to X-linked hydrocephalus syndrome?
In CATVariant, X-linked hydrocephalus syndrome is linked to 1 analyzed protein: L1CAM (Neural cell adhesion molecule L1).
How many genetic variants are linked to X-linked hydrocephalus syndrome?
26 variants: 8 are classified as disease-causing (pathogenic or likely pathogenic) in ClinVar and 16 are of uncertain significance or have conflicting reports.
Which uncertain variants in X-linked hydrocephalus syndrome look disease-causing?
None of the uncertain variants currently reaches the likely-pathogenic range on computable evidence alone.
About this data
Variant–disease links come from ClinVar, Open Targets and UniProt, pooled from the latest public CATVariant analysis of each human protein. Evidence scores use the ACMG/AMP Bayesian points scale with computable criteria only (position among known disease variants, rarity in gnomAD, calibrated predictors, deep mutational scanning); there is no family or patient data, so they prioritise variants for expert review and never classify them.
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