Novel splice site CACNA1A mutation causing episodic ataxia type 2.

Episodic ataxia type 2 (EA-2) is an autosomal dominant neurological disorder, characterized by episodes of ataxia, vertigo, nausea, nystagmus, and fatigue, associated with acetazolamide responsiveness. The disease is caused by mutations in the P/Q-type calcium channel Ca(v)2.1 subunit gene, CACNA1A, located on chromosome 19p13.2. We analyzed a family with 13 affected individuals for linkage to this locus and reached a two-point maximum LOD score of 4.48. A novel CACNA1A mutation, IVS36-2A>G, at the 3' acceptor splice site of intron 36 was identified by sequencing. It is the first described CACNA1A acceptor splice site mutation and the most C-terminal EA-2-causing mutation reported to date.