Genetic localization of the familial adult myoclonic epilepsy (FAME) gene to chromosome 8q24.

Objective: To identify the genetic locus for the familial adult myoclonic epilepsy (FAME) gene.

Background: Idiopathic generalized epilepsy (IGE) represents a collection of disorders in which affected individuals present with recurring seizures that have diffuse onset on EEG. These individuals have no known structural cerebral lesions or other identifiable etiology. IGE accounts for approximately 40% of all epilepsies. FAME is a type of IGE characterized by autosomal dominant inheritance, adult onset, varying degrees of myoclonus in the limbs, rare tonic-clonic seizures, and a benign course.

Methods: We investigated four previously reported Japanese kindreds and performed a genome-wide screen with genetic linkage analysis.

Results: Clinical characterization and sampling of 30 individuals in four families revealed that 21 had the FAME phenotype. We defined a 4.6-cM region on chromosome 8q24 (maximum lod score of 4.86 at theta = 0) that contains the FAME gene.

Conclusions: The identification and characterization of the FAME gene allows us to better understand the molecular basis of FAME. Such knowledge may provide clues to understanding the molecular basis of the clinically similar, and more common, juvenile myoclonic epilepsies, and other generalized seizure disorders that have thus far eluded genetic approaches.