Basilar-type migraine: clinical, epidemiologic, and genetic features.

BACKGROUND

It remains uncertain whether basilar-type migraine (BM) is a subtype of migraine with typical aura (MTA) or a distinct phenotype or genotype.

OBJECTIVE

To analyze the symptomatology, familial distribution, and genotype of BM.

METHODS

The authors recruited 105 families comprising 362 patients with MTA or BM (International Classification of Headache Disorders-1 criteria). Among these patients, 38 patients from 29 families had BM. In 12 of the families with BM with an apparently dominant inheritance the authors sequenced all exons of the CACNA1A (chromosome 19) and ATP1A2 (chromosome 1) genes responsible for most cases of the autosomal dominantly inherited familial hemiplegic migraine and performed a linkage analysis of chromosome 1 and 19 with a nonparametric or autosomal dominant parametric model using an affected only analysis.

RESULTS

BM occurred in 10% (38/362) of patients with MTA. The basilar-type aura had a median duration of 60 minutes and comprised vertigo 61%, dysarthria 53%, tinnitus 45%, diplopia 45%, bilateral visual symptoms 40%, bilateral paresthesias 24%, decreased level of consciousness 21%, hypacusia 21%, and ataxia 5%. The relative frequency of the individual basilar-type symptoms was not different from patients with hemiplegic migraine from a previous study. The patients with BM were equally distributed among the 105 families with MTA (p = 0.37). The attacks of MTA were identical in families with or without BM. No causative mutations and no linkage was identified.

CONCLUSIONS

Basilar-type aura seemingly may occur at times in any patient with migraine with typical aura. There is no firm clinical, epidemiologic, or genetic evidence that BM is an independent disease entity different from MTA.