MCCC1

Chr 3

methylcrotonyl-CoA carboxylase subunit 1

Also known as: MCC-B, MCCA, MCCCalpha

NCBI Gene: 56922 ENSG00000078070 UniProt: Q96RQ3

This gene encodes the large subunit of 3-methylcrotonyl-CoA carboxylase, which catalyzes the carboxylation of 3-methylcrotonyl-CoA to form 3-methylglutaconyl-CoA as part of leucine catabolism. Biallelic mutations cause 3-methylcrotonyl-CoA carboxylase 1 deficiency, an autosomal recessive disorder of leucine metabolism. The pathogenic mechanism involves loss of enzyme function leading to impaired leucine breakdown.

GeneReviews ResearchSummary from RefSeq, OMIM, UniProt, Mechanism

This gene encodes the large subunit of 3-methylcrotonyl-CoA carboxylase. This enzyme functions as a heterodimer and catalyzes the carboxylation of 3-methylcrotonyl-CoA to form 3-methylglutaconyl-CoA. Mutations in this gene are associated with 3-Methylcrotonylglycinuria, an autosomal recessive disorder of leucine catabolism. [provided by RefSeq, Jul 2008]

GeneReviews ResearchGenerating clinical summary…

Primary Disease Associations & Inheritance

UniProt3-methylcrotonoyl-CoA carboxylase 1 deficiency

Clinical highlights

Gene-disease validity (ClinGen)

3-methylcrotonyl-CoA carboxylase deficiency · ARDefinitivesufficient evidence for diagnostic panels

Interpreting a novel variant

Loss of function is the curated mechanism (Gene2Phenotype), though the gene is not strongly LoF-constrained in the population — weigh truncating variants against that tolerance.Curated gene-level mechanism — a prior for triage, not a per-variant call.

Active trials

Pubs (1 yr)

—

P/LP submissions

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P/LP missense

0.90

LOEUF

LOF

Mechanism· G2P

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GeneReview available — MCCC1