BENIGN CHILDHOOD EPILEPSY WITH CENTROTEMPORAL SPIKES AND THE FOCAL SHARP WAVE TRAIT IS NOT LINKED TO THE FRAGILE-X REGION

Benign childhood epilepsy with centrotemporal spikes (BCECS, benign ro landic epilepsy) is a common form of genetically determined localisati on-related epilepsy of childhood. The characteristic age-dependent foc al sharp wave (fsw) found on the EEG in this disorder segregates as a dominant trait in families with probands with BCECS. Seizures occur in a significant proportion of individuals with the fragile X syndrome i n association with EEG abnormalities comparable to those found in BCEC S. The possibility of a common genetic basis for these disorders was i nvestigated by linkage analysis. Six pedigrees with probands with BCEC S were analysed using a marker locus DXS548, close to the fragile X si te, fra (X). Obligate recombinants between DXS548 and the fsw trait we re observed in all six families. Assuming X-linked dominant inheritanc e and penetrance values of 0.4 (male) and 0.1 (female) a negative lod score of -6,823 was obtained at zero recombination and lod scores of - 2.0 at 10 cM either side of the fra (X) locus. These results exclude a n important candidate gene for this common childhood disorder.