This condition is inherited in an autosomal recessive manner
Spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME), sometimes called Jankovic–Rivera syndrome, is a very rare neurodegenerative disease whose symptoms include slowly progressive muscle wasting (atrophy), predominantly affecting distal muscles, combined with denervation and myoclonicseizures. Only 12 known families are described in scientific literature to have SMA-PME.
The ASAH1 Gene codes for acid ceramidase which is an enzyme found in lysosomes. The lysosome breaks down acid ceramidase and the fatty acid component is then used to produce myelin. Myelin is a coating around the nerves in the body which help transfer signals from nerve cell to nerve cell and increase transmission rate. In patients with SMA-PME, the cermidase function is reduced to only be 33.33% effective. The lack of myelin resulting from the lack of acid ceramidase break down leads to nerve cell damage.