Frequency of the different mutations causing spinocerebellar ataxia (SCA1, SCA2, MJD/SCA3 and DRPLA) in a large group of Brazilian patients

Arquivos de Neuro-Psiquiatria

Iscia Lopes-cendesi²  Hélio G.a. Teive¹  Maria E Calcagnotto¹  Jaderson C. Da Costa¹  Francisco Cardoso¹  Erika Viana¹  Jaime A. Maciel¹  João Radvany¹  Walter O. Arruda²  Paulo C. Trevisol-bittencourt¹  Pedro Rosa Neto¹  Isabel Silveira²  Carlos E. Steiner¹  Walter Pinto-júnior¹  André S. Santos¹  Ylmar Correa Neto¹  Lineu C. Werneck¹  Abelardo Q.c. Araújo¹  Gerson Carakushansky¹  Luiz R. Mello¹  Laura B. Jardim¹  Guy A. Rouleau² 

[1] ,McGill University Montreal General Hospital Centre for Research in NeuroscienceMontreal QC ,Canada

关键词: neurodegenerative disease;    spinocerebellar ataxia type 1;    spinocerebellar ataxia type 2;    spinocerebellar ataxia type 3;    Machado-Joseph disease;    dentatorubropallidoluysian atrophy;    trinucleotide repeat expansion;    doença neurodegenerativa;    ataxia espinocerebelar tipo 1;    ataxia espinocerebelar tipo 2;    ataxia espinocerebelar tipo 3;    doença de Machado-Joseph;    atrofia dentatorubropalidoluisiana;    expansão de trinucleotídeo CAG;   

DOI  :  10.1590/S0004-282X1997000400001

来源: SciELO

【 摘 要 】

Spinocerebellar ataxia type 1 (SCA1), spinocerebellar ataxia type 2 (SCA2) and Machado-Joseph disease or spinocerebellar ataxia type 3 (MJD/SCA3) are three distinctive forms of autosomal dominant spinocerebellar ataxia (SCA) caused by expansions of an unstable CAG repeat localized in the coding region of the causative genes. Another related disease, dentatorubropallidoluysian atrophy (DRPLA) is also caused by an unstable triplet repeat and can present as SCA in late onset patients. We investigated the frequency of the SCA1, SCA2, MJD/SCA3 and DRPLA mutations in 328 Brazilian patients with SCA, belonging to 90 unrelated families with various patterns of inheritance and originating in different geographic regions of Brazil. We found mutations in 35 families (39%), 32 of them with a clear autosomal dominant inheritance. The frequency of the SCA1 mutation was 3% of all patients; and 6 % in the dominantly inherited SCAs. We identified the SCA2 mutation in 6% of all families and in 9% of the families with autosomal dominant inheritance. The MJD/SCA3 mutation was detected in 30 % of all patients; and in the 44% of the dominantly inherited cases. We found no DRPLA mutation. In addition, we observed variability in the frequency of the different mutations according to geographic origin of the patients, which is probably related to the distinct colonization of different parts of Brazil. These results suggest that SCA may be occasionally caused by the SCA1 and SCA2 mutations in the Brazilian population, and that the MJD/SCA3 mutation is the most common cause of dominantly inherited SCA in Brazil.

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