Familial hemiplegic migraine in the west of Scotland: a clinical and genetic study of seven families.

OBJECTIVES: Clinical and genetic characterisation of families in the west of Scotland with familial hemiplegic migraine. METHODS: Families with familial hemiplegic migraine were identified via probands attending the regional paediatric neurology and child development centre. All available family members were assessed clinically and genetic linkage studies for the known familial hemiplegic migraine gene locus on chromosome 19 were carried out on three families. RESULTS: Seven unrelated kindreds with familial hemiplegic migraine were identified. Clinical information was obtained on 138 family members, 27 of whom fulfilled the International Headache Society criteria for familial hemiplegic migraine. Whereas the severity, duration, frequency, and temporal progression of acute hemiplegic migrainous attacks showed pronounced variability within and between families, and even in the same individual over time, no true clinical heterogeneity of the condition was apparent. Genetic linkage analysis gave results consistent with linkage to the familial hemiplegic migraine gene locus on chromosome 19p in one family. In the other two families, evidence against linkage was obtained. There was no significant clinical difference between these three families. CONCLUSIONS: This study provides characterisation of the clinical features of familial hemiplegic migraine in a British population. Significant variability was found in the frequency and character of migraine attacks within and between families, and no true clinical heterogeneity was identified. On the other hand, further evidence for genetic heterogeneity of the condition was found.