This is difficult on clinical grounds alone. It may be suspected by examination of the urine for conjugates of methacrylic acid. The diagnosis is made by sequencing the mutated gene. Differential diagnosis * Leigh syndrome
3-Hydroxyisobutyryl-CoA deacylase deficiency
Malonyl-CoA decarboxylase deficiency
3-Methylcrotonyl-CoA carboxylase deficiency
2-Methylbutyryl-CoA dehydrogenase deficiency
Pyruvate kinase deficiency
3-Hydroxy-3-methylglutaryl-CoA lyase deficiency
2,4 Dienoyl-CoA reductase deficiency
Succinyl-CoA:3-oxoacid CoA transferase deficiency