Quantitative Genetic Study of Seizures

本申请要求4年的资金，以继续在癫痫发作的遗传易感性研究的综合方案。这项工作的长期目标是确定近亲繁殖小鼠的癫痫易感性基因，并将其作为对患有常见癫痫的人类进行重点研究的基础。在本项目前期，我们利用QTL定位方法研究了2个自交系小鼠的癫痫易感性，分别是抗实验性癫痫发作的B6和易感性小鼠D2。本工作的结果确定了一个主要影响位点Szs1 （chr）。1)，以及其他几个作用中等的基因座，包括Szs11 (chr。5)和Szs13 (chr。15)。我们假设这些基因座背后的基因基本上是

This application requesting 4 years of funding to continue a comprehensive program in the study of genetic susceptibility to seizures. The long term goal of this work is to identify seizure susceptibility genes in inbred mice and use them as the basis for focused studies in humans with common forms of epilepsy. In the initial stages of this project, we used quantitative trait locus (QTL) mapping to study seizure susceptibility in 2 inbred mouse strains: B6, which is resistant to experimental seizures, and D2, which is susceptible. Results of this work identified a locus of major effect, Szs1 (chr.1), and several other loci of moderate effect including Szs11 (chr. 5) and Szs13 (chr. 15). We hypothesize that the genes underlying these loci are fundamentally important in the regulation of neuronal excitability since they were detected consistently in diverse screening paradigms using kainic acid, pentylenetetrazol and electroshock. Thus, over the past funding period, we have focused on characterizing each of these loci further, primarily through a congenic strain-candidate gene strategy. Results have led to nomination of a gene for Szs1 and confirmation of Szs11 and Szs13 in congenic strains. The putative Szs1 gene is Kcnj10 which encodes an inward-rectifying potassium channel and plans to generate formal proof that it is Szs1 comprise the first aim of this proposal. Studies will involve creation of transgenic and knock-in mice and will utilize in vivo and in vitro electrophysiology as well as behavioral tests of seizure susceptibility. Aim 2 involves continued refinement of Szs11 and Szs13 using the prototype strategy we developed for Szs1. Thus, based on completion of congenic strains begun during the last funding period and systematic creation of interval specific congenic strains, we plan to reduce the critical intervals to 3 cM and then begin candidate gene analysis. The third aim involves initiation of new QTL studies designed to exploit the phenotypic diversity exhibited by other inbred mouse strains for identifying seizure susceptibility loci. Overall, we hypothesize that genetic variation associated with seizure susceptibility in mice is related to that which underlies common human epilepsies; and further, that by identifying key loci in mice greater insight will be afforded into mechanisms of seizures and their abolition in humans. Recent data from our lab documenting a significant association between variants of KCNJ10 and idiopathic generalized epilepsy support this concept and justify the continued use of QTL mapping for identifying seizure susceptibility loci in mice.