GCDH and glutaryl-CoA dehydrogenase deficiency: Glutaric aciduria type I (GA-I) is caused by autosomal recessive mutations in the GCDH gene (cytogenetic location: 19p13.2) resulting in glutaryl-CoA dehydrogenase (GCDH; EC 1.3.99.7) deficiency) [1] and elevated concentrations of glutaryl-CoA, glutaric acid (GA), 3-hydroxyglutaric acid (3-OH-GA) and glutarylcarnitine (C5DC) in body tissues.