MMADHC
Chr 2ARmetabolism of cobalamin associated D
Also known as: C2orf25, CL25022, HMAD, MACD, MAHCD, cblD
This gene encodes a mitochondrial protein that regulates cobalamin (vitamin B12) metabolism and trafficking, specifically controlling the biosynthesis and proportion of two essential coenzymes, methylcobalamin and adenosylcobalamin. Mutations cause methylmalonic aciduria and homocystinuria cblD type, an autosomal recessive disorder of cobalamin metabolism that can present with megaloblastic anemia and affects both amino acid and organic acid metabolism. The gene shows low constraint against loss-of-function variants (pLI 0.00002, LOEUF 0.994), which is consistent with its autosomal recessive inheritance pattern.
Definitive — sufficient evidence for diagnostic panels
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Typical tolerance to LoF variation
Tolerant to missense variation
ClinVar Variant Classifications
0 submitted variants in ClinVar
Protein Context — Lollipop Plot
MMADHC · 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