MOCS3
Chr 20ARmolybdenum cofactor synthesis 3
Also known as: MOCODB2, UBA4
The protein encoded by MOCS3 performs two essential cellular functions: it thiocarboxylates sulfur carrier proteins required for molybdenum cofactor biosynthesis and modifies specific tRNAs involved in protein synthesis. Mutations cause molybdenum cofactor deficiency type B2, an autosomal recessive disorder that typically presents in the neonatal period with severe neurological manifestations including seizures and developmental delays due to impaired function of molybdoenzymes. The gene is highly constrained against loss-of-function variants (pLI approaching 1), reflecting its essential cellular role.
Primary Disease Associations & Inheritance
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Highly tolerant — LoF variants common in population
Mild missense constraint
The highest-scoring mechanism for this gene is dominant-negative.
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
MOCS3 · 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