Genetics of inherited human epilepsies

Review of the use of topiramate for treatment of bipolar disorders

Lithium alone or in combination with other psychotherapeutic drugs has long been the gold standard of management for bipolar disorder (BD). Recognition of its limitations in the acute and chronic management of BD has led to the development of alternative therapies. One such approach involves the use of antiepileptic drugs (AEDs). The AED topiramate is currently being studied in the efficacy and management of BD. Topiramate has mechanisms in common with other AEDs, including sodium channel-blocking activity and enhancement of cerebral GABA concentrations. Open-label trials have evaluated topiramate at mean daily doses of 100 to 300 mg in various BD subtypes, including acute mania, depression, rapid-cycling, mixed states, and BD refractory to other medications. Results from these trials suggest topiramate may be efficacious in BD subtypes, particularly in rapid-cycling patients and those refractory to conventional treatment. Its side effect profile appears benign when used as monotherapy or in combination with other mood stabilizers. Placebo-controlled, double-blind studies are warranted to evaluate topiramate further in BD.

Genetics of epilepsy: current status and perspectives

Epilepsy affects more than 0.5% of the world's population and has a large genetic component. The most common human genetic epilepsies display a complex pattern of inheritance and the susceptibility genes are largely unknown. However, major advances have recently been made in our understanding of the genetic basis of monogenic inherited epilepsies. Progress has been particularly evident in familial idiopathic epilepsies and in many inherited symptomatic epilepsies, with the discovery that mutations in ion channel subunits are implicated, and direct molecular diagnosis of some phenotypes of epilepsy is now possible. This article reviews recent progress made in molecular genetics of epilepsy, focusing mostly on idiopathic epilepsy, and some types of myoclonus epilepsies. Mutations in the neuronal nicotinic acetylcholine receptor alpha4 and beta2 subunit genes have been detected in families with autosomal dominant nocturnal frontal lobe epilepsy, and those of two K(+) channel genes were identified to be responsible for underlying genetic abnormalities of benign familial neonatal convulsions. The voltage-gated Na(+) -channel (alpha1,2 and beta1 subunit), and GABA receptor (gamma2 subunit) may be involved in the pathogenesis of generalized epilepsy with febrile seizure plus and severe myoclonic epilepsy in infancy. Mutations of Ca(2+)-channel can cause some forms of juvenile myoclonic epilepsy and idiopathic generalized epilepsy. Based upon these findings, pathogenesis of epilepsy as a channelopathy and perspectives of molecular study of epilepsy are discussed.