ASAH1 and proximal spinal muscular atrophy: A complete knockout of AC activity has not been found in man, likely due to embryonic lethality, but partial loss-of-function mutations in the gene encoding AC (ASAH1) results in two severe but clinically distinct inherited disorders, Farber’s lipogranulomatosis and spinal muscular atrophy with myoclonic epilepsy [11,12,13].