3-methylcrotonylglycinuria (Q86116)

Isolated 3-methylcrotonyl-CoA carboxylase (MCC) deficiency is an organic aciduria due to a disorder of leucine catabolism. The phenotype is variable, ranging from neonatal onset with severe neurological involvement to asymptomatic adults. Most symptomatic patients have normal growth and development until presenting with an acute metabolic crisis between 2 and 33 months of age manifesting as vomiting, opisthotonus, involuntary movements, seizures, coma and apnoea, and that are often accompanied by severe hypoglycaemia, ketoacidosis and mild hyperammonemia.