Background. Dystonia is a common hyperkinetic movement disorder in children; however, making an early and definitive diagnosis of dystonia can sometimes be challenging for clinicians.

Case. Herein, we report a case of a 16 years-old girl presenting with laryngeal dystonia due to compound heterozygosity of a known pathogenic and a novel variant in the ATM gene. Serum alpha-fetoprotein level was elevated. Serum IgG, IgA, IgM and IgE levels were within normal range. Treatment with L-DOPA had no benefit. Her symptoms were dramatically improved by localized botulinum toxin injections.

Conclusion. Mutations in the ATM gene show a wide phenotypic spectrum from severe classical early-onset ataxia-telangiectasia (A-T) to late-onset milder variant A-T. Our findings highlight the importance of recognizing laryngeal dystonia as one of the clinical signs of A-T.

Keywords: ATM gene, ataxia–telangiectasia, dysarthria, dystonia