Phenotypic variability of episodic ataxia type 2 mutations: a family study.

Background: Episodic ataxia type 2 (EA2) is characterized by paroxysmal bouts of ataxia and progressive cerebellar dysfunction. Other manifestations may also be associated, such as migraine attacks with or without aura, absence epilepsy and mental retardation.

Methods: To describe the intrafamilial variability of clinical manifestations of 3 patients harboring a novel CACNA1A point mutation in exon 7 (nucleotide insertion c.1063dupG) typical of EA2 mutation.

Results: All 3 patients presented paroxysmal bouts of ataxia, but age of onset, associated symptoms and symptoms at clinical onset were clearly distinct with hemiplegic migraine attacks in the father, absence epilepsy in one child and mental retardation in the other child.

Conclusion: Typical manifestations of EA2 may be associated and temporally preceded by rare manifestations such as hemiplegic migraine attacks, epilepsy and mental retardation. Moreover, patients sharing a given CACNA1A mutation may present very different phenotypes even within the same family.