FAMILIAL HEMIPLEGIC MIGRAINE - LOCALIZATI ON OF A RESPONSIBLE GENE ONCHROMOSOME-19

Familial hemiplegic migraine is an autosomal dominant disorder of unkn own pathogenesis in which the migrainous attacks are marked by the occ urrence of a transient hemiplegia during the aura. The aim of our stud y was the identification of the affected gene. The first step was the chromosomal mapping of the affected gene, for which we used a << candi date gene >> strategy. The first candidate gene was the gene responsib le for CADASIL. While investigating CADASIL, mapped previously to chro mosome 19, we observed that some patients had recurrent attacks of mig raine with aura. Although the clinical and neuroimaging features of fa milial hemiplegic migraine differ markedly from CADASIL, we hypothesiz ed that the same gene could be involved in the pathogenesis of both co nditions. We chose two large pedigrees for linkage analysis of familia l hemiplegic migraine. A maximum lodsore > 8 was found with two marker s that are strongly linked to CADASIL. Multilocus linkage analysis loc ated the affected gene within an interval of about 30 cM on chromosome 19, containing the gene responsible for CADASIL. At this step it's no t possible to conclude that CADASIL and familial hemiplegic migraine a re due to the same mutated gene. It will be necessary to analyse other familial hemiplegic migraine and CADASIL families in order to reduce the size of their respective interval and ultimately identify the muta ted gene(s).