PROGRESSIVE MYOCLONUS EPILEPSIES (PME)

GENETICS

PATTERN OF INHERITANCE

This syndrome composes many possible underlying etiologies, the pattern of inheritance therefore varies and may be autosomal recessive, maternally inherited (mitochondrial disorders) another form of inheritance or the pathogenic variant may have arisen de novo.

KNOWN GENES

The gene implicated depends on the underlying etiology. A repeat expansion in EPM1 is implicated in ~90% of cases of Unverricht-Lundborg disease, most cases of Lafora disease are accounted for by pathogenic variants in EPM2A and EPM2B and there are more than a dozen genes implicated in the neuronal ceroid lipofuscinoses, the most prevalent of which is CLN2.

FAMILY HISTORY OF SEIZURES/EPILEPSY

Depending on the underlying cause, a family history of seizures/epilepsy may be present.