MMAB

Chr 12q24.11

metabolism of cobalamin associated B

Aliases:: cblB, CFAP23
MANE:: ENST00000545712.7

OMIM: 607568 ↗NCBI: 326625 ↗Ensembl ↗

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Predicted protein structure

AlphaFold predicted structure

MMAB · Q96EY8

v62025-08-01

Predicted Aligned Error matrix for MMAB — diagonal shows residue index, colour shows pairwise prediction confidence (lower is better) — Predicted Aligned Error

Mean pLDDT

81.8/ 100

Confident

250 residues

Confidence breakdown

Very high(≥ 90)66%
Confident(70–90)9%
Low(50–70)5%
Very low(< 50)19%

Open interactive 3D viewer

AlphaFold (Jumper et al., 2021) · CC BY 4.0

Clinical relevance (Genomics England PanelApp)

Diagnostic Grade (Green)

DDG2P
BIALLELIC, autosomal or pseudoautosomal
Hyperammonaemia
BIALLELIC, autosomal or pseudoautosomal
Intellectual disability
BIALLELIC, autosomal or pseudoautosomal
Likely inborn error of metabolism
BIALLELIC, autosomal or pseudoautosomal
Undiagnosed metabolic disorders
BIALLELIC, autosomal or pseudoautosomal
Childhood onset dystonia, chorea or related movement disorder
Fetal anomalies
BIALLELIC, autosomal or pseudoautosomal

Disease associations (Open Targets)

methylmalonic aciduria, cblB type
0.82
Vitamin B12-responsive methylmalonic acidemia type cblB
0.82
methylmalonic aciduria cblb type
0.56
vitamin B12-responsive methylmalonic acidemia
0.56
methylmalonic acidemia
0.54
hereditary disease
0.49
neurodegenerative disease
0.48
Methylmalonic aciduria
0.46
hearing loss disorder
0.40
gout
0.39

Score is the Open Targets composite evidence score (0-1). Higher = stronger gene-disease association.

Protein function (UniProt)

Corrinoid adenosyltransferase MMAB

Converts cob(I)alamin to adenosylcobalamin (adenosylcob(III)alamin), a coenzyme for methylmalonyl-CoA mutase, therefore participates in the final step of the vitamin B12 conversion (PubMed:12514191). Generates adenosylcobalamin (AdoCbl) and directly delivers the cofactor to MUT in a transfer that is stimulated by ATP-binding to MMAB and gated by MMAA (Probable)