Methylmalonic aciduria and homocystinuria type cblD: genes and variants
Methylmalonic aciduria and homocystinuria type cblD is linked to 1 analyzed protein (MMADHC). 2 DNA variants are known to cause it; 50 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 Methylmalonic aciduria and homocystinuria type cblD
MMADHC: Cobalamin trafficking protein CblD
It directs intracellular cobalamin toward the methylcobalamin and adenosylcobalamin pathways needed for methionine and methylmalonyl-CoA metabolism. Biallelic pathogenic variants cause cblD disease, producing isolated or combined methylmalonic acidemia and homocystinuria.
2 disease-causing and 50 uncertain variants in MMADHC are linked to Methylmalonic aciduria and homocystinuria type cblD.
Known disease-causing variants in Methylmalonic aciduria and homocystinuria type cblD
| Variant | Position | Protein part | Clinical label |
|---|---|---|---|
| MMADHC L259P | 259 | Disease-causing (★★) | |
| MMADHC Y249C | 249 | Disease-causing |
Diseases related to Methylmalonic aciduria and homocystinuria type cblD
- Cobalamin C disease, also linked to MMADHC
- Disorders of Intracellular Cobalamin Metabolism, also linked to MMADHC
Frequently asked questions
Which genes are linked to Methylmalonic aciduria and homocystinuria type cblD?
In CATVariant, Methylmalonic aciduria and homocystinuria type cblD is linked to 1 analyzed protein: MMADHC (Cobalamin trafficking protein CblD).
How many genetic variants are linked to Methylmalonic aciduria and homocystinuria type cblD?
95 variants: 2 are classified as disease-causing (pathogenic or likely pathogenic) in ClinVar and 50 are of uncertain significance or have conflicting reports.
Which uncertain variants in Methylmalonic aciduria and homocystinuria type cblD 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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