Mendelian forms of benign
myoclonic epilepsies where a chromosomal locus has been defined include (1) the autosomal dominant (AD)
juvenile myoclonic epilepsy (JME) in chr. 6p11, (2) the autosomal dominant
childhood absence epilepsy which evolves to JME in chr. 1p, (
3) familial adult myoclonic epilepsy of Yasuda and Inazuki, and (4) possibly JME within the
idiopathic generalized epilepsy susceptibility gene in chr. 8 reported by Zara et al (1995). Other
myoclonic epilepsy syndromes with onset in the first year of life (Aicardi's Neonatal (
Early) Myoclonic Encephalopathy, West's Syndrome, Dravet's Severe
Myoclonic Epilepsy, and Dravet's Benign
Myoclonic Epilepsy of Infancy), in early childhood (Lennox-Gastaut-
Dravet Syndrome, Myoclonic Variant of Lennox Gastaut
Dravet Syndrome,
Myoclonic-Astatic Epilepsy of Doose, Benign
Myoclonic Epilepsies (BME), or even in late childhood (
Childhood Absence Epilepsy with myoclonias, vs.
Myoclonic Absence Epilepsy) are probably genetically complex diseases. Amongst the
progressive myoclonus epilepsy syndromes, specific mutations have already been defined in
Unverricht Lundborg disease,
ceroid lipofuscinoses 3 or Spielmayer Voight syndrome within Battens disease,
sialidosis, dentadorubropallidoluysian
atrophy and the mitochondrial
syndrome MERRF. Most recently our laboratories established the locus for Lafora's disease in chr. 6q and results are speedily moving towards the definition of its mutation.