A novel CACNA1A mutation associated with adult-onset, paroxysmal head tremor.

CACNA1A mutations cause a range of disorders with diverse, sometimes overlapping clinical features. Point mutations, including missense mutations, nonsense mutations, splicing mutations and small deletions/insertions, result in a variety of phenotypes including episodic ataxia type 2 (EA2) and familial hemiplegic migraine type 1 (FHM1). These 2 conditions show clinical overlap with spinocerebellar ataxia type 6 (SCA6), generally caused by CAG repeat expansions in the coding region of CACNA1A. We report a novel missense mutation in CACNA1A presenting with adult-onset, paroxysmal head tremor responsive to acetazolamide.