ALDH7A1 and glutaryl-CoA dehydrogenase deficiency: Another limitation is the reliance on biochemical parameters alone to determine efficacy of AASS inhibition for PDE-ALDH7A1 and other disorders of lysine metabolism such as glutaric aciduria type I.15 This is a limitation of the Aldh7a1 mouse model, which does not have a naive neurologic phenotype.25 Of note, current standard of care recommendations for patients with PDE-ALDH7A1 are also based, in large part, on improvement of the same metabolites.2,18,19,26 Another limitation is the use of germline KO to model the impact of AASS inhibition.