GCDH and glutaryl-CoA dehydrogenase deficiency: For example a clinical picture of significant dystonia, macrocephaly and MRI revealing widened Sylvian fissures and basal ganglia abnormalities may be confirmed as glutaric aciduria type 1 with urine organic acid analysis and genetic study of the glutaryl CoA dehydrogenase (GCDH) gene (261, 262).