GENE REFERENCE / HGNC:6936

MCCC1

methylcrotonyl-CoA carboxylase subunit 1

protein-coding gene3q27.1Gene information

What does this gene do?

The MCCC1 gene provides instructions for making one part (the alpha subunit) of an enzyme called 3-methylcrotonoyl-CoA carboxylase or MCC. These alpha subunits join with smaller beta subunits made from the MCCC2 gene; six of these pairings together form a functioning enzyme. The alpha subunit also includes a region for binding to the B vitamin biotin, which is required for the enzyme to function.

The MCC enzyme is found in mitochondria, which are the energy-producing centers inside cells. This enzyme plays a critical role in breaking down proteins obtained from food. Specifically, it is responsible for the fourth step in the breakdown of leucine, an amino acid that is a building block of many proteins. This step converts a molecule called 3-methylcrotonyl-CoA to a molecule called 3-methylglutaconyl-CoA. Additional chemical reactions convert 3-methylglutaconyl-CoA into molecules that are later used for energy.

Source: MedlinePlus, National Library of Medicine. Source publication: 2024-04-01. Source review: 2024-03.

ClinGen reviews

ClinGen reviews the evidence linking a particular gene to a condition. Each rating below describes the strength of that link. It does not classify a variant in your DNA file.

Condition	Inheritance	Evidence
3-methylcrotonyl-CoA carboxylase deficiencyMONDO:0018950 · Evaluated 2019-10-25	Autosomal recessive	DefinitiveAminoacidopathy Gene Curation Expert Panel

ClinVar records

These numbers show what has been submitted to ClinVar. They cannot tell you how likely you are to have a condition.

Submitted alleles: 1,061
Submissions for variants in or overlapping this gene: 1,743
Submissions explicitly reporting this gene: 1,696
Alleles reported pathogenic / likely pathogenic: 223
VariationIDs with uncertain significance: 322
VariationIDs with conflicting classifications: 43

The rows count different things: alleles, submissions or VariationIDs. Their categories can overlap, so do not add them together. Pathogenic/likely pathogenic counts exclude structural variants that merely overlap a gene. A dash in the source means “not reported,” not zero.

NCBI produces the gene-summary file each week using counts recorded at the start of the month. The numbers may differ from those on the live ClinVar website. Read the field definitions ↗

View this gene in ClinVar ↗

YOUR DNA FILE

Can your DNA file tell you about MCCC1?

From a DNA test kit (such as 23andMe, AncestryDNA or MyHeritage). These kits check a fixed list of about 600,000 to 700,000 positions across your whole genome. ClinVar lists 223 alleles in MCCC1 reported as pathogenic or likely pathogenic. A kit checks only some of these positions, and often none of them.

From whole genome sequencing (a VCF file). Sequencing reads most of your genome. Your file lists the places where your DNA differs from the reference genome. Some regions are hard to sequence, including parts of some genes that have near-identical copies elsewhere, and a VCF file does not record which positions were read well.

If a variant is not in your file, that does not mean you don’t have it.

What BioDecode checks

BioDecode compares every variant in your file with ClinVar, on your own computer. For each match, it shows the ClinVar classification, the review status and the condition it was reported for. Your file is not uploaded.

A ClinVar classification applies to one particular variant and the condition it was reported for. It does not tell you about other variants in MCCC1.

BioDecode cannot fill gaps in your test, diagnose a condition or replace clinical testing.

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