Defects in GCDH are reponsible for glutaric acidemia type 1 (GA1), an inherited metabolic disorder which prevents the complete breakdown of lysine and tryptophan (Strauss et al., 2003 ▶; Strauss & Morton, 2003 ▶; Goodman et al., 1998 ▶). The gene discussed is GCDH; the disease is glutaryl-CoA dehydrogenase deficiency.