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Título

SPINOCEREBELLAR ATAXIA TYPE 42 WITH VARIANT OF UNCERTAIN SIGNIFICANCE IN CACNA1G GENE - CASE REPORT

Apresentação do caso

RFR, 11 years old, presented with global retardation in neuropsychomotor developmental milestones and a previous diagnosis of Autistic Spectrum Disorder. At 6 years of age, he started having episodes of bilateral tonic-clonic and focal dysperceptive seizures. He took carbamazepine, without response, with partial control with valproic acid. One year later, he began to present dysmetria, chorea of the upper limbs and trunk ataxia, besides findings such as ocular and retroauricular telangiectasias. Metabolic screening and alpha-fetoprotein dosage were performed, without alterations. Magnetic resonance imaging of the brain demonstrated hyperintensity on T2 and Flair images involving periventricular white matter, especially near the atria of the lateral ventricles, besides slight ectasia of the posterior horns of the lateral ventricles. Electroencephalogram with an encephalopathy pattern and no discharges. A genetic panel was performed and identified a variant of uncertain significance, described as NM_018896.5, in the CACNA1G gene, associated with spinocerebellar ataxia type 42. The patient presents with a slowly progressive evolution of cerebellar symptoms since its onset.

Discussão

Spinocerebellar ataxias (SCAs) constitute a heterogeneous group of neurodegenerative disorders. SCA 42 is a rare subtype, with an estimated prevalence of less than 1 per 1 000 000 individuals. It has autosomal dominant inheritance and is a mutation caused by pathogenic variant in the calcium channel 1G (CACNA1G) gene that encodes T-type voltage-dependent calcium channels, widely expressed in the central nervous system, playing an important role in the regulation of membrane potential and calcium-mediated signaling pathway. Thus, mutations can impair cell behavior and cause neurodegenerative disorders. It has great clinical and genetic variability, a slowly progressive course, and variable age of onset and severity. It presents clinical signs such as ataxia, dysarthria, and alterations in neuropsychomotor development, as observed in the case described. Treatment has no proven efficacy. Early multidisciplinary therapies help to improve quality of life.

Comentários finais

Spinocerebellar ataxia type 42 is a rare subgroup of a heterogeneous group of neurodegenerative diseases. It shows great clinical variability, and its follow-up is important. Early diagnosis helps in genetic counseling and patient support.

Palavras Chave

Spinocerebellar ataxia; neurodegenerative diseases; genetic.

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Não há conflito de interesse.