A specific diagnosis for some of these diseases has been possible for a long time, on the basis of characteristic stigmata detected by pathological investigation. Numerous advances in genetics now permit #LY2603618 purchase randurls[1|1|,|CHEM1|]# direct molecular diagnosis in most cases. We

will focus here on the genetic bases of Unverricht-Lundborg disease and Lafora’s disease. Other PMEs with their corresponding loci and genes are listed in Table II. 81-120 Unverricht-Lundborg disease Unverricht-Lundborg Inhibitors,research,lifescience,medical disease is an autosomal recessive PME classically with onset between 6 and 15 years of age, a slow progression, rare, late, and mild mental deterioration, and cerebellar ataxia.121,122 However, more dramatic outcomes have been described, often precipitated by phenytoin

prescription.123 More recently, late-onset forms of the disease have been reported.124 Both the Baltic and Mediterranean forms of the disease are caused by mutations in the cystatin B gene located in the region 21q22.3.125,126 Inhibitors,research,lifescience,medical Rare point mutations and deletions in the coding region of the gene81-84 lead to a loss of function of cystatin B. More frequently, expansion of a dodecamer (CGC CGC CCC GCG)n repeat in the 5′ untranslated region of the gene85-88 Inhibitors,research,lifescience,medical decreases transcription. Normal alleles contain two to three copies of the dodecamer, whereas mutant alleles contain more than 30 repeats of the dodecamer. Preliminary studies have not provided evidence of a correlation between the size of the dodecamer expansion and age at onset of the disease.88 There Inhibitors,research,lifescience,medical are probably premutation states, since intermediate size alleles with 12 to 17 dodecamer repeats have been detected in individuals with normal phenotype who were able to transmit pathologic alleles to their offspring.86 Table II Inherited progressive myoclonus epilepsies. AD, autosomal dominant; AR, autosomal recessive, aProgressive myoclonic epilepsy may be a clinical form of the disease. The presence of these two types of mutations varies according

Inhibitors,research,lifescience,medical to the geographic origin of affected families. of The Baltic form of the disease is generally caused by a point mutation in one copy of the cystatin B gene and expansion of the dodecamer in the other copy or, more rarely, by point mutations in both copies of the gene. The Mediterranean form of the disease, characterized by frequent consanguinity, results from expansion of the dodecamer on both copies of the cystatin B gene. Table III Principal inherited disorders with epilepsy as a part of phenotype. AD, autosomal dominant; AR, autosomal recessive. *With unusual characteristics: the mutation can be passed through phenotypically normal males (norma! male carriers) and their daughters … Cystatin B is a cystein-protease inhibitor that is thought to protect against apoptosis, but the mechanism leading to Unverricht-Lundborg disease remains to be elucidated.