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Searching for modulating effects of SCA2, SCA6 and DRPLA CAG tracts on the Machado‐Joseph disease (SCA3) phenotype
Author(s) -
Jardim L.,
Silveira I.,
Pereira M. L.,
Do Céu Moreira M.,
Mendonça P.,
Sequeiros J.,
Giugliani R.
Publication year - 2003
Publication title -
acta neurologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.967
H-Index - 95
eISSN - 1600-0404
pISSN - 0001-6314
DOI - 10.1034/j.1600-0404.2003.00046.x
Subject(s) - machado–joseph disease , anticipation (artificial intelligence) , spinocerebellar ataxia , age of onset , trinucleotide repeat expansion , genetics , biology , allele , cerebellar ataxia , disease , degenerative disease , ataxia , medicine , gene , neuroscience , artificial intelligence , computer science
Context – Machado–Joseph disease (MJD/SCA3) is an autosomal dominant cerebellar ataxia of adult onset. The variability in age at onset and the complex and heterogeneous neurologic findings indicate that MJD, caused by a major gene, is modulated by modifier factors. Objective – To study if the polymorphic CAG repeats at other loci (namely, SCA2, SCA6 and DRPLA) thus acted as modifier factors of this disease. Design – Case–control. Setting – Ambulatory care in a referral center. Patients – A convenience sample of 39 unrelated, Brazilian patients with MJD. Main outcome measures: age of onset, anticipation, clinical subtypes and neurological findings. Results – Fasciculations were associated with CAG repeat length of the long SCA2 allele (Mann–Whitney U ‐test, P < 0.03, after Bonferroni procedure). Other measures (age of onset, anticipation, clinical types and other neurological signs) were not associated with CAG repeat length of SCA2, SCA6 and DRPLA genes. Conclusions – The present results show that the CAG tract of SCA2 gene interferes with MJD phenotype. Further studies, with patients of other origins and with typing of other (CAG) n loci , are necessary.