GCDH and glutaryl-CoA dehydrogenase deficiency: Glutaric aciduria type 1 (GA1; OMIM #231670) is a rare neurometabolic disorder of lysine, hydroxylysine, and tryptophan metabolism caused by biallelic pathogenic variants in the GCDH gene, encoding the mitochondrial matrix protein glutaryl‐CoA dehydrogenase (GCDH, EC 1.3.8.6) [1, 2].