Focal occipital seizures

are frequent.127 Until recently, diagnosis was established by observation of intracellular polyglucosan inclusions (Lafora bodies) on skin biopsies.128 Direct molecular diagnosis is now possible. Linkage analysis and homozygosity mapping localized the gene in the region 6q23-25.129,130 The gene, identified by positional cloning,89,90 encodes a protein tyrosine phosphatase, laforin, which is a tyrosine kinase inhibitor. Laforin is thought to be involved in glycogen metabolism. Homozygous deletions and several homozygous point mutations in the coding part of the gene have been found in affected families.89,90 At least one other locus Inhibitors,research,lifescience,medical is probably also responsible for Lafora disease.131,132 Inherited neurologic disorders and chromosomal disorders with epilepsy as a part of the phenotype Epilepsy is observed among complex neurological or

extraneurological symptoms in numerous chromosomal disorders and inherited disorders affecting Inhibitors,research,lifescience,medical the central nervous system. They cannot be described in detail in this review and most are listed in Tables III and IV. 106,133-147 The frequency of epilepsy in these complex syndromes is variable. Table IV Principal chromosomal disorders associated with epilepsy. Conclusion Genetic Inhibitors,research,lifescience,medical studies of previously well-defined epileptic syndromes have led to the identification of causative genes in some cases, but also to the identification of new familial epileptic syndromes that are not yet included in the international classification of epilepsies and epileptic syndromes.59 Inhibitors,research,lifescience,medical In the future, this classification will probably take into account these new familial epileptic disorders with their particular electroclinical Inhibitors,research,lifescience,medical features and SRT1720 nmr prognoses. The genetic

heterogeneity of epilepsies is becoming more and more apparent. Different genes, which may or not be functionally linked, and different mutations may cause the same familial epileptic syndrome. At the same time, significant intrafamilial phenotypic heterogeneity can often be observed. This is particularly clear in the GEFS+ syndrome. One hypothesis is that the expression of the mutated genes differs among family members, causing Phosphatidylinositol diacylglycerol-lyase clinical heterogeneity. Alternatively, the gene may intervene in epileptogenesis at a very general level, affecting epileptic susceptibility or modulating the epileptogenic threshold, and other genetic or environmental factors may influence the electroclinical profile of the disease in each affected subject. There are many pathophysiological mechanisms underlying inherited epilepsies. The functional or morphological consequences of the mutations that give rise to an epileptic process are extremely variable.