Introduction: Spinocerebellar ataxia type 13 is a rare autosomal dominant disease caused by point mutations in the KCNC3 gene coding for the Kv3.3 voltage-gated potassium channel. This disease can present different neurodevelopmental and neurodegenerative forms.
Case report: We present a case of a child who had trunk and appendicular ataxia, exuberant gait ataxia, tremor, dysarthria, and dysrhythmic and scanning speech. She presented a delay and difficulty in acquiring fine motor skills. Cerebral magnetic resonance imaging showed moderate hypoplasia of the cerebellum. A pathogenic variant c1268 G>A p.(Arg423His) in heterozygosity in the KCNC3 gene was detected, allowing the diagnosis of Spinocerebellar Ataxia type 13. Later, the same diagnosis was established in the patient's father. However, he gradually improved his ataxia and motor function throughout his life.
Discussion: Unlike most spinocerebellar ataxias, including the other spinocerebellar ataxia type 13 phenotypes, this one does not lead to progressive ataxia. Children with this disease should be follow-up by a multidisciplinary team and referred to an early intervention program. A regular neurologic examination is recommended to evaluate disease progression.
Key words: Cerebellar Ataxia, Cerebellum Hypoplasia, Genetic Disease, Hereditary Ataxia, Spinocerebellar Ataxia type 13