No evidence for association between the KCNQ3 gene and susceptibility to idiopathic generalized epilepsy

Idiopathic generalized epilepsy (IGE) comprises a heterogeneous group of di sorders, in which a high genetic predisposition and a complex mode of inher itance have been suggested. Recent identification of ion channel gene mutat ions in Mendelian epileptic disorders suggests genetically driven neuronal hyperexcitability as one important factor in epileptogenesis. Mutations in two neuronal voltage-gated potassium channel genes (KCNQ2 and KCNQ3) have a lready been shown to cause epilepsy (BFNC), and we now tested the hypothesi s that genetic variation in the KCNQ3 gene confers liability to common IGE subtypes. Length variation of two intragenic polymorphic markers (D8S558 an d D8S1835) were therefore assessed in 71 nuclear families ascertained for a n affected child. However, the transmission-disequilibrium-test did not sho w significant differences between the transmitted and non-transmitted paren tal alleles. Thus, our findings do not provide evidence that genetic variat ion in the KCNQ3 gene exerts a relevant effect in the etiology of common IG E subtypes. (C) 2000 Elsevier Science B.V. All rights reserved.