GCDH and glutaryl-CoA dehydrogenase deficiency: Glutaric acidemia type I (GA I, McKusick 23167; OMIM # 231670) is an autosomal recessive inherited neurometabolic disease caused by deficiency of glutaryl-CoA dehydrogenase activity (GCDH, EC 1.3.99.7), with an estimated incidence of 1∶30,000-1∶100,000 live-births, reaching a much higher prevalence in some communities (1∶300) [1]–[5].