Mapping of a locus for a familial autosomal recessive idiopathic myoclonicepilepsy of infancy to chromosome 16p13

Myoclonic epilepsies with onset in infancy and childhood are clinically and etiologically heterogeneous. Although genetic factors are thought to play an important role, to date very little is known about the etiology of these disorders. We ascertained a large Italian pedigree segregating a recessive idiopathic myoclonic epilepsy that starts in early infancy as myoclonic se izures, febrile convulsions, and tonic-clonic seizures. We typed 304 micros atellite markers spanning the 22 autosomes and mapped the locus on chromoso me 16p13 by linkage analysis. A maximum LOD score of 4.48 was obtained for marker D16S3027 at recombination fraction 0. Haylotype analysis placed the critical region within a 3.4-cM interval between D16S3024 and D16S423. The present report constitutes the first example of an idiopathic epilepsy that is inherited as an autosomal recessive trait.