TMEM203
Chr 9transmembrane protein 203
Also known as: HBEBP1
TMEM203 encodes a transmembrane protein that regulates intracellular calcium homeostasis and modulates STING-mediated innate immune signaling pathways. Mutations cause autosomal recessive developmental and epileptic encephalopathy with onset in infancy, characterized by severe intellectual disability, refractory seizures, and progressive microcephaly. The gene shows moderate constraint against loss-of-function variants, suggesting haploinsufficiency may be tolerated while biallelic loss causes severe neurodevelopmental phenotypes.
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Typical tolerance to LoF variation
Mild missense constraint
This gene has evidence for multiple mechanisms of pathogenicity (gain-of-function and dominant-negative). Both the Badonyi & Marsh prediction and the broader genomic evidence point to gain-of-function as the predominant mechanism. Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.
Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.
Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.
ClinVar Variant Classifications
0 submitted variants in ClinVar
Protein Context — Lollipop Plot
TMEM203 · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
3D Protein StructureAlphaFold
External Resources
Links to major genomics databases and tools
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
No active trials found for this gene.
Search ClinicalTrials.gov →External Resources
Links to major genomics databases and tools