The response to corticosteroid therapy in a 3-year-old boy with ataxia-telangiectasia is reported from University of Siena, Italy. The diagnosis was confirmed by molecular testing. Improvements in neurologic signs were noted by the parents when betamethasone was used occasionally to treat asthmatic bronchitis. After 2 or 3 days continuous therapy with betamethasone, 0.1 mg/kg/24 hrs, divided every 12 hours, a beneficial effect was observed. The improvement in stance, gait, and skilled movements was dramatic after 2 weeks of treatment, but adverse effects including increased appetite and body weight and moon face occurred by 4 weeks. Methylprednisolone, 2 mg/kg/24 hrs, divided every 12 hrs, substituted at 4 weeks, was ineffective, and was discontinued. At 6 months follow-up, without therapy, the child showed severe signs of CNS impairment. 
COMMENT. Despite the potential adverse effects of corticosteroids in a patient already immunocompromised, a trial of betamethasone was considered appropriate in view of the poor neurologic prognosis in ataxia-telangiectasia. Limited trials of gabapentin, pregabalin and tiagabine were moderately effective in the control of ataxia in an adult with ataxia-telangiectasia.