RESUMEN
Spinocerebellar ataxias are a high clinically and genetically heterogeneous group of neurodegenerative disorders, usually belongs to autosomal dominant hereditary cerebellar ataxia. Spinocerebellar ataxia type 5 (SCA5) is one of the extremely rare subtypes and caused by heterozygous mutation of SPTBN2 gene. A case of infant-onset SCA5 patient is reported, mainly manifested as global developmental delay, ataxia and dysarthria, carrying the heterozygous missense variant c.1438C>T (p. Arg480Trp) in the SPTBN2 gene. This mutation may have an important impact on functional regions of the β-Ⅲ spectrin, leading to the occurrence of disease.
RESUMEN
Spinocerebellar ataxias (SCAs) are autosomal dominant neurodegenerative disorders which disrupt the afferent and efferent pathways of the cerebellum that cause cerebellar ataxia. Spectrin beta non-erythrocytic 2 (SPTBN2) gene encodes the β-III spectrin protein with high expression in Purkinje cells that is involved in excitatory glutamate signaling through stabilization of the glutamate transporter, and its mutation is known to cause spinocerebellar ataxia type 5. Three years and 5 months old boy with delayed development showed leukodystrophy and cerebellar atrophy in brain magnetic resonance imaging (MRI). Diagnostic exome sequencing revealed that the patient has heterozygous mutation in SPTBN2 (p.Glu1251Gln) which is a causative genetic mutation for spinocerebellar ataxia type 5. With the patient's clinical findings, it seems reasonable to conclude that p.Glu1251Gln mutation of SPTBN2 gene caused spinocerebellar ataxia type 5 in this patient.