Spinal muscular atrophy-progressive myoclonic epilepsy syndrome

Spinal muscular atrophy-progressive myoclonic epilepsy syndrome (SMA-PME), also known as spinal muscular atrophy with progressive myoclonic epilepsy or Jankovic-Rivera syndrome, is an extremely rare genetic disorder that combines features of lower motor neuron disease with progressive myoclonic epilepsy. The condition is caused by mutations in the ASAH1 gene, which encodes the enzyme acid ceramidase involved in lipid metabolism. This enzyme deficiency leads to accumulation of ceramide in cells, affecting both the nervous system and other body systems. The disease typically presents in early childhood with progressive muscle weakness and atrophy due to degeneration of anterior horn cells in the spinal cord, resembling spinal muscular atrophy. Over time, patients develop myoclonic seizures, action myoclonus, and sometimes other seizure types that become increasingly difficult to control. Additional features may include tremor, sensorineural hearing loss, cognitive decline, and respiratory difficulties. The progressive nature of the condition leads to increasing disability, with loss of ambulation and worsening epilepsy over the course of years. There is currently no cure or disease-specific treatment for SMA-PME. Management is supportive and symptomatic, focusing on antiepileptic medications to control seizures (though seizures are often refractory to treatment), physical therapy and rehabilitation to maintain mobility, respiratory support as needed, and management of other complications. Research into enzyme replacement therapy and other targeted approaches is ongoing but remains in early stages. Prognosis is variable but generally poor, with progressive neurological deterioration over time.

Common questions about Spinal muscular atrophy-progressive myoclonic epilepsy syndrome