By contrast, two other inborn errors of lysine degradation, glutaric aciduria type 1 (GA1) caused by mutations in GCDH (MIM 231 670) and pyridoxine-dependent epilepsy caused by mutations in ALDH7A1 (PDE-ALDH7A1; MIM 266 100), are serious diseases. Here, ALDH7A1 is linked to pyridoxine-dependent epilepsy.