The ASAH1 gene encodes in humans the acid ceramidase enzyme. It is mapped to 8p22. This gene encodes a member of the acid ceramidase family of proteins. Alternative splicing results in multiple transcript variants,at least one of which encodes a preproprotein that is proteolytically processed. Processing of this preproprotein generates alpha and beta subunits that heterodimerize to form the mature lysosomal enzyme,which catalyzes the degradation of ceramide into sphingosine and free fatty acid. This enzyme is overexpressed in multiple human cancers and may play a role in cancer progression. Mutations in this gene are associated with the lysosomal storage disorder,Farber lipogranulomatosis,and a neuromuscular disorder,spinal muscular atrophy with progressive myoclonic epilepsy.