More recently, AC deficiency has been shown to cause a form of spinal muscular atrophy (SMA) associated with progressive myoclonic epilepsy (SMA-PME) [3] or SMA without PME [4], which are characterized by proximal muscle weakness and generalized atrophy of muscles due to degeneration of spinal motor neurons [4]. This evidence concerns the gene ASAH1 and proximal spinal muscular atrophy.