RESUMO
OBJECTIVE: To analyze clinical and genetic characteristics of patients with the verified rare forms of autosomal recessive spinocerebellar ataxias, ATX-ANO10 and ATX-SYNE1. MATERIAL AND METHODS: Six unrelated patients with established diagnoses were examined: 4 patients with ATX-ANO10 and 2 patients with ATX-SYNE1. Brain MRI and nerve conduction study were performed. To screen for cognitive impairment, the scale for the Assessment and Rating of Ataxia (SARA), and the Montreal Cognitive Assessment Scale (MoCA) were used. Mutation screening included panel sequencing on the Illumina MiSeq platform. RESULTS: Six variants were found in the ANO10 gene: the previously described pathogenic nonsense mutations c.G1025A (p.W342X) and c.C1244G (p.S415X), as well as novel probably pathogenic variants c.1477-2A>G and c.G101T (p.W34L) and missense mutations c.A110C (p.N37T) and c.T104C (p.L35P) of undetermined significance. A novel nonsense mutation c.C8911T (p.Q2971X) and a previously described pathogenic variant c.C4939T (p.Q1647X) were found in the SYNE1 gene. The clinical presentation of the ATX-ANO10 and ATX-SYNE1 was typical presenting with slowly progressive cerebellar ataxia with pyramidal signs, with young onset and cerebellar atrophy according to brain MRI study. CONCLUSION: We provided first-ever data on clinical features and mutation spectrum In Russian patients with ATX-ANO10 and ATX-SYNE1. The phenotype of these ataxias is nonspecific, so the method of choice for molecular diagnostics is massive parallel sequencing.
Assuntos
Anoctaminas , Proteínas do Citoesqueleto , Proteínas do Tecido Nervoso , Ataxias Espinocerebelares , Humanos , Ataxias Espinocerebelares/genética , Ataxias Espinocerebelares/diagnóstico por imagem , Masculino , Feminino , Proteínas do Tecido Nervoso/genética , Adulto , Proteínas do Citoesqueleto/genética , Anoctaminas/genética , Mutação , Proteínas Nucleares/genética , Pessoa de Meia-Idade , Imageamento por Ressonância Magnética , Códon sem Sentido , Mutação de Sentido Incorreto , Adolescente , Adulto JovemRESUMO
OBJECTIVE: To assess the incidence of spinocerebellar ataxia type 8 (SCA8) in patients with progressive cerebellar ataxia and describe the clinical features of the SCA8 phenotype in Russian patients. MATERIAL AND METHODS: Genotyping of CTA/CTG repeats in ATXN8OS gene was carried out in 411 patients with degenerative ataxias using fragment analysis. SCA types 1, 2, 3 and 6 as well as Friedreich's ataxia were preliminarily excluded. All patients underwent brain MRI study. Scale for the Assessment and Rating of Ataxia (SARA), and the Montreal Cognitive Assessment Scale (MoCA) to screen for cognitive impairment were used. RESULTS: Six patients with SCA8 (1.5%) were identified as carriers of the expansion in the ATXN8OS gene (91-152 CTA/CTG repeats). All cases were sporadic. Age of onset ranged from 14 to 42 years. All patients had slowly progressive cerebellar ataxia, oculomotor disturbances, dysarthria, pyramidal signs, and two patients had cognitive impairment. In one patient the clinical presentation corresponded to multiple system atrophy cerebellar type (ataxia, orthostatic hypotension, cerebellum and brainstem atrophy). Brain MRI study in all patients revealed cerebellar atrophy. CONCLUSION: SCA8 is a rare form of autosomal dominant ataxia with a predominance of the classical phenotype. All identified cases of SCA8 were sporadic, which should be taken into account when planning genetic testing in patients with spinocerebellar ataxia.