Progressive myoclonic epilepsy.

Progressive myoclonic epilepsy (PME) is a disease complex and is characterized by the development of relentlessly progressive myoclonus, cognitive impairment, ataxia, and other neurologic deficits. It encompasses different diagnostic entities and the common causes include Lafora body disease, neuronal ceroid lipofuscinoses, Unverricht-Lundborg disease, myoclonic epilepsy with ragged-red fiber (MERRF) syndrome, sialidoses, dentato-rubro-pallidal atrophy, storage diseases, and some of the inborn errors of metabolism, among others. Recent advances in this area have clarified molecular genetic basis, biological basis, and natural history, and also provided a rational approach to the diagnosis. Most of the large studies related to PME are from south India from a single center, National Institute of Mental Health and Neurological Sciences (NIMHANS), Bangalore. However, there are a few case reports and small series about Lafora body disease, neuronal ceroid lipofuscinoses and MERRF from India. We review the clinical and research experience of a cohort of PME patients evaluated at NIMHANS over the last two decades, especially the phenotypic, electrophysiologic, pathologic, and genetic aspects.