Familial adult myoclonic epilepsy (FAME): clinical features, molecular characteristics, pathophysiological aspects and diagnostic work-up.

Abstract

Familial adult myoclonic epilepsy (FAME) is a rare autosomal dominant disorder characterized by myoclonus and seizures. The genetic variant underlying FAME is an intronic repeat expansion composed of two different pentamers: an expanded TTTTA, which is the motif originally present at the locus, and an insertion of TTTCA repeats, which is usually located at the 3' end and likely corresponds to the pathogenic part of the expansion. This repeat expansion has been identified so far in six genes located on different chromosomes, which remarkably encode proteins with distinct cellular localizations and functions. Although the exact pathophysiological mechanisms remain to be clarified, it is likely that FAME repeat expansions lead to disease independently of the gene where they occur. We herein review the clinical and molecular characteristics of this singular genetic disorder, which interestingly shares clinical features with other more common neurological disorders whose etiology remains mainly unsolved.