Abstracts

Familial partial epilepsy with variable foci (FPEVF) is a recently described familial partial epilepsy syndrome. Linkage has been reported for FPEVF to chromosome 22q11-12 in two French-Canadian and one Dutch family. We have identified an extended Australian family with multiple members showing clinical characteristics of FPEVF. The familial inheritance of the epilepsy seen within this family is indicative of a strong underlying genetic component, with autosomal dominant inheritance. Here we report the results of genetic linkage analysis studies in this family. We conducted a genome-wide scan using 400 microsatellite markers, followed by linkage analysis to identify regions of the genome likely to contain the causative gene. Two potential candidate regions on chromosomes 22 and 19 were identified. A significant lod score of 3.45 was obtained on chromosome 22q and a multipoint lod score of 2.63 was obtained on chromosome 19, both occurring at [sim]30 cM from the proximal end of the chromosome. The peaks span [sim]8 and [sim] 9 cM on chromosomes 19 and 22, respectively. Fine mapping confirmed the region of linkage on chromosome 22 as falling within the candidate regions previously identified in two French-Canadian and Dutch FPEVF families (22q11-12). We have identified linkage in an Australian family with the clinical phenotype of FPEVF to a region within that reported in three previous families on chromosome 22q. This result strongly supports the causative gene for this syndrome lying within this region. Additionally we have identified a second region of linkage on chromosome 19q that may represent the site of a modifier gene.