article
ATXN3, ATXN7, CACNA1A, and RAI1 genes and mitochondrial polymorphism a10398g did not modify age at onset in spinocerebellar ataxia type 2 patients from South America
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Autor
Godeiro Junior, Clécio de Oliveira
Pereira, Fernanda S.
Monte, Thais L.
Locks-Coelho, Lucas D.
Silva, Amanda S. P.
Barsottini, Orlando
Pedroso, José L.
Cornejo-Olivas, Mario
Mazzetti, Pilar
Vargas, Fernando R.
Lima, Maria Angélica F. D.
Linden Junior, Hélio van der
Toralles, Maria Betânia Pereira
Medeiros, Paula F. V.
Ribeiro, Erlane
Braga-Neto, Pedro
Salarini, Diego
Castilhos, Raphael M.
Pereira, Maria Luiza Saraiva
Jardim, Laura Bannach
Resumen
The spinocerebellar ataxia type 2 (SCA2) is a rare autosomal dominant neurodegenerative disease caused by expansions of a CAG repeat tract at ATXN2 gene. These repeats range from 22 to 31 CAG in normal alleles and from 32–34 to 64 and more, in expanded alleles. ATXN2 expansion accounts for around 50 % of the variability in age at onset (AO) of symptoms . Former studies reported that other genes may be responsible for small effects in SCA2 AO. The CAG repeats’ length (CAGn) at RAI1 gene would explain 4 % of the remaining variance in AO in 46 SCA2 patients with no clear-cut geographical origin. Two publications studied candidate
genes among patients with highly discordant AO, from an original sample of 394 patients from Holguin, Cuba
Their data pointed to the CAGn at CACNA1A gene [3] and to a polymorphism of the mitochondrial complex I A10398G (rs2853826) as modifiers of SCA2 AO. We have previously found that longer CAGn at ATXN3 gene were associated with earlier ages at onset in a former sample of 49 SCA2 patients from Brazil. SCA2 AO was associated with the CAGn at ATXN7 gene in a European cohort of 289 SCA2 patients but this association was not confirmed in a second cohort [6]. Since replications in additional, independent samples of patients are required to validate a genetic association, we aimed to investigate these same loci in a South American
cohort of SCA2 in order to add evidences on their role as modifiers of AO in this disease.