title: Genetic polymorphism at spinocerebellar ataxia 1 and 2 loci in Brazil.
abstract: Dynamic mutation involves the expansion of a tandem arrayed DNA sequence that is polymorphic in the population. This mechanism is associated with neurological/neuromuscular disorders and the pathology depends on the extension of the repeated tract, with a specific threshold for each disease. We made a PCR-based characterization of allelic polymorphism of SCA1 and SCA2 loci in a sample of 200 pairs of chromosomes in a population in Rio de Janeiro and found 23 different alleles at the SCA1 locus, varying from 10 to 39 CAG repeats (mean 27.7 +/- 3.3, mode 28) and 10 different alleles ranging from 19 to 29 CAG (mean 22.1 +/- 1.0, mode 22) at the SCA2 locus. The level of heterozygosis was 53% (SCA1) and 8% (SCA2).
authors.affiliation: Human Genetics Service, Department of Cell Biology and Genetics, State University of Rio de Janeiro, Rio de Janeiro, RJ, Brazi.
authors.forename: Stenio F P
authors.initials: SF
authors.lastname: Duarte
authors.forename: Raquel S
authors.initials: RS
authors.lastname: Gestinari
authors.forename: Mário
authors.initials: M
authors.lastname: Campos Junior
authors.forename: Márcia M G
authors.initials: MM
authors.lastname: Pimentel
authors.forename: Marcelo A Costa
authors.initials: MA
authors.lastname: Lima
mesh_terms: D000293:Adolescent; D000328:Adult; D000067696:Ataxin-1; D000067528:Ataxins; D001938:Brazil; D004252:DNA Mutational Analysis; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic / Q000235:genetics*; D011506:Proteins / Q000235:genetics; D020754:Spinocerebellar Ataxias / Q000235:genetics*
chemical_list: C000593749:ATXN1 protein, human; D000067696:Ataxin-1; D000067528:Ataxins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D011506:Proteins