3-methylcrotonyl-CoA carboxylase 2 deficiency (MONDO_0008862) is any 3-methylcrotonyl-CoA carboxylase deficiency in which the cause of the disease is a mutation in the MCCC2 gene. Also known as: 3-Methylcrotonyl-CoA carboxylase 2 deficiency, 3-methylcrotonyl-CoA carboxylase deficiency caused by mutation in MCCC2, MCCC2 3-methylcrotonyl-CoA carboxylase deficiency.