The MCCC1 and MCCC2 genes make protein subunits that come together to form an enzyme called 3-methylcrotonyl-CoA carboxylase. This enzyme plays an essential role in breaking down proteins from the diet. Specifically, the enzyme is responsible for the fourth step in processing leucine. If a mutation in the MCCC1 or MCCC2 gene reduces or eliminates the activity of 3-methylcrotonyl-CoA carboxylase, the body is unable to process leucine properly. As a result, toxic byproducts of leucine processing build up to harmful levels, damaging the brain and nervous system. This condition is inherited in an autosomal recessive pattern.
3-Methylcrotonyl-CoA carboxylase deficiency
2-Methylbutyryl-CoA dehydrogenase deficiency
Glutaminase deficiency
Pyruvate kinase deficiency
Malonyl-CoA decarboxylase deficiency
2,4 Dienoyl-CoA reductase deficiency
3-Hydroxy-3-methylglutaryl-CoA lyase deficiency
Multiple carboxylase deficiency