A novel mutation in CACNA1A associated with hemiplegic migraine, cerebellar dysfunction and late-onset cognitive decline.

Hemiplegic migraine (HM) is a rare and severe subtype of migraine with aura, characterized by some degree of hemiparesis and other aura symptoms. Mutations in three genes (CACNA1A, ATP1A2 and SCN1A) have been detected in familial and, more rarely, in sporadic cases. The disease can be complicated by permanent neurological deficits, the most frequent one being a cerebellar syndrome; in addition, mental retardation has been recognized as part of the phenotypic spectrum. Here, we report a Caucasian male with a novel CACNA1A mutation and an unusual clinical phenotype: the patient, who had had a history of only two HM attacks, sought medical advice at age 49 primarily because of increasing cognitive decline accompanied by cerebellar dysfunction. While common neurodegenerative causes were excluded, neuropsychological evaluation revealed a distinct profile of deficits of a subcortico-prefrontal type as previously reported in patients with cerebellar dysfunction. This suggests a possible causal link between cerebellar and cognitive disturbances in this patient; in addition to these pathophysiological aspects, we review of the role of the cerebellum in cognition.