RESUMO
BACKGROUND: Deletions and duplications of single exons or exon groups account for a large proportion of the PARK2 gene mutations described in juvenile autosomal recessive Parkinson's disease (PD). METHODS: We analyzed rearrangements in exons 1 to 12 of the PARK2 gene in Russian sporadic patients with early-onset PD (EOPD) and late-onset PD (LOPD). RESULTS: The frequency of EOPD and LOPD patients carrying these mutations was 12.4% and 3.8%, respectively. The most frequent rearrangements were detected in exons 3 and 4. The odds ratio for EOPD in individuals carrying PARK2 exon deletions and duplications was 13.95 (95% confidence interval [CI], 1.846-105.46; P = .0022). In addition, we found a correlation between exon rearrangements in PARK2 and the age at onset of PD, presence of dystonia, and symmetrical course of the disease. CONCLUSIONS: Exon rearrangements in the PARK2 gene play a significant role in the pathogenesis of sporadic PD in Russian patients.
Assuntos
Éxons/genética , Rearranjo Gênico/genética , Doença de Parkinson/genética , Ubiquitina-Proteína Ligases/genética , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/classificação , Doença de Parkinson/epidemiologia , Federação Russa/epidemiologia , Adulto JovemRESUMO
Autosomal recessive juvenile parkinsonism (AR-JP) is a form of hereditary parkinsonism characterized by variable clinical presentations and caused by mutations in a novel gene, parkin, on chromosome 6q25.2-27. Until now, no Russian cases of parkin-associated AR-JP have been reported on. We recruited 16 patients from 11 Russian families with dopa-responsive movement disorders according to the following criteria: 1) family history compatible with autosomal recessive inheritance; 2) onset of symptoms at =30 years of age; and 3) the lack of mutations in the GTP cyclohydrolase I gene (in sporadic cases). Mutation screening of the parkin gene was carried out by a semiquantitative PCR assay and direct sequencing of the coding region. Six different parkin mutations (both deletions and point mutations) were identified in the index cases from four families, including a novel point mutation in the donor splice site (IVS1+1G-->A). The majority of our parkin-associated cases were characterized by early-onset dopa-responsive parkinsonism with benign course and slow progression (5 patients from two families have been followed for as long as 18-36 years), and 1 patient had a phenotype of dopa-responsive dystonia. This first description of Russian patients with AR-JP and molecularly proven parkin mutations confirms the widespread occurrence of this polymorphic hereditary extrapyramidal disorder.