Trihexyphenidyl for treatment of dystonia in ataxia telangiectasia: a case report

Ataxia telangiectasia (AT) is an autosomal recessive multisystem disorder caused by mutations of ATM gene. And dystonia may develop as a late manifestation in typical AT. Here we report a novel homozygous frameshift ATM mutation (c.1402_1403delAA; p. K468Efs*18) in a 10-year-old male. The patient was diagnosed as typical AT according to clinical presentations which included progressive cerebellar ataxia, oculocutaneous telangiectasia, immune deficiency, and cerebellar atrophy. The genetic finding confirmed the diagnosis. Severe dystonia was presented in late stage of this disease. After 3 months of trihexyphenidyl treatment, the frequency of dystonia was reduced significantly. Although dystonia is not uncommon in phenotype spectrum of AT, compared with other symptoms of this syndrome, such as cerebellar ataxia and dysarthria, dystonia can be treated.