[Acute intermittent familial ataxia: report of a new family]

INTRODUCTION. Acute intermittent familial ataxia is a rare disorder with autosomal dominant inheritance and unknown etiology which usually in childhood or adolescence. CASE 1. A 33-years-old woman who suffered from giddiness, gait ataxia, dysarthria and somnolence episodes. These episodes lasted between 4 and 72 hours. They generally occurred within a framework of emotional or physical stress. The following tests were performed: hemogram and biochemistry, blood and urine toxicology, immunological tests, cerebrospinal-fluid study, electrocardiogram, electroencephalogram, trunk and visual evocated potentials, cerebral computed tomography and cerebral magnetic resonance imaging. None of them gave significative results. CASE 2. A 12-years-old boy, son of the previous woman, who suffered from somnolence, gait ataxia and dysarthria with acute beginning. The same tests than in the above case were performed together with metabolic studies. There were no pathological findings in this case, either. The symptoms disappeared gradually in 6 days. His familial history led to a diagnosis of acute intermittent familial ataxia. A year later he suffered from a similar disorder and he was immediately treated with acetazolamide. The symptoms disappeared in 2 hours. CONCLUSIONS. Acute intermittent familial ataxia is a disorder of difficult identification. It can be easily confused with other periodical ones, because its diagnosis has to be based on the clinical findings and on the familial history. For this purpose, a therapeutic test with acetazolamide can be useful, since in most cases a spectacular clinical improvement has been observed.