RESUMO
BACKGROUND: Variants within the leucine-rich repeat kinase 2 gene are recognized as the most frequent genetic cause of Parkinson's disease. Leucine-rich repeat kinase 2 variation related to disease susceptibility displays many features that reflect the nature of complex, late-onset sporadic disorders like Parkinson's disease. METHODS: The Genetic Epidemiology of Parkinson's Disease Consortium recently performed the largest genetic association study for variants in the leucine-rich repeat kinase 2 gene across 23 different sites in 15 countries. RESULTS: Herein, we detail the allele frequencies for the novel risk factors (p.A419V and p.M1646T) and the protective haplotype (p.N551K-R1398H-K1423K) nominated in the original publication. Simple population allele frequencies not only can provide insight into the clinical relevance of specific variants but also can help genetically define patient groups. CONCLUSIONS: Establishing individual patient-based genomic susceptibility profiles that incorporate both risk factors and protective factors will determine future diagnostic and treatment strategies.
Assuntos
Frequência do Gene , Predisposição Genética para Doença , Doença de Parkinson/epidemiologia , Doença de Parkinson/genética , Proteínas Serina-Treonina Quinases/genética , Estudos de Associação Genética , Genética Populacional , Genótipo , Haplótipos , Humanos , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina , Epidemiologia Molecular , Polimorfismo de Nucleotídeo ÚnicoRESUMO
Mitochondrial dysfunction occurs early in late-onset sporadic Parkinson's disease (PD), but the mitochondrial protein network mediating PD pathogenesis is largely unknown. Mutations in the mitochondrial serine-threonine kinase PINK1 have recently been shown to cause the early-onset autosomal recessive PARK6 variant of PD. We have now tested a candidate interactor protein of PINK1, the mitochondrial translation initiation factor 3 (MTIF3) for involvement in PD pathogenesis. In two independent case-control collectives, the c.798C>T polymorphism of the MTIF3 gene showed allelic association with PD, with a maximal significance of p=0.0073. An altered function of variant MTIF3 may affect the availability of mitochondrial encoded proteins, lead to oxidative stress and create vulnerability for PD.
Assuntos
Fatores de Iniciação em Eucariotos/genética , Predisposição Genética para Doença/genética , Doenças Mitocondriais/genética , Proteínas Mitocondriais/genética , Doença de Parkinson/genética , Polimorfismo Genético/genética , Análise Mutacional de DNA , Feminino , Marcadores Genéticos/genética , Testes Genéticos , Genótipo , Humanos , Desequilíbrio de Ligação , Masculino , Doenças Mitocondriais/metabolismo , Doenças Mitocondriais/fisiopatologia , Mutação/genética , Doença de Parkinson/metabolismo , Doença de Parkinson/fisiopatologia , Valor Preditivo dos Testes , Proteínas Quinases/genéticaRESUMO
Sepiapterin reductase (SPR) gene is an enzyme which catalyses the final step of tetrahydrobiopterin synthesis (BH4) and was implicated in Parkinson's disease (PD) pathogenesis as a candidate gene for PARK3 locus. A number of studies yielded association of the PARK3 locus with PD, and SPR knockout mice were shown to display parkinsonian features. To evaluate the role of SPR gene polymorphisms in diverse populations in PD, we performed collaborative analyses in the Genetic Epidemiology of Parkinson Disease (GEO-PD) Consortium. A total of 5 single nucleotide polymorphisms (3 in the promoter region and 2 in the 3' untranslated region [UTR]) were genotyped. Fixed as well as random effect models were used to provide summary risk estimates of SPR variants. A total of 19 sites provided data for 6547 cases and 9321 controls. Overall odds ratio estimates varied from 0.92 to 1.01. No overall association with the SPR gene using either fixed effect or random effect model was observed in the studied population. I(2) Metric varied from 0% to 36.2%. There was some evidence for an association for participants of North European/Scandinavian descent with the strongest signal for rs1876487 (odds ratio = 0.82; p value = 0.003). Interestingly, families which were used to map the PARK3 locus, have Scandinavian ancestry suggesting a founder effect. In conclusion, this large association study for the SPR gene revealed no association for PD worldwide. However, taking the initial mapping of the PARK3 into account, the role of a population-specific effect warrants consideration in future studies.
Assuntos
Oxirredutases do Álcool/genética , Loci Gênicos/genética , Doença de Parkinson/genética , Estudos de Associação Genética , Predisposição Genética para Doença , Genótipo , Humanos , Polimorfismo de Nucleotídeo Único , Regiões Promotoras GenéticasRESUMO
BACKGROUND: Background The leucine-rich repeat kinase 2 gene (LRRK2) harbours highly penetrant mutations that are linked to familial parkinsonism. However, the extent of its polymorphic variability in relation to risk of Parkinson's disease (PD) has not been assessed systematically. We therefore assessed the frequency of LRRK2 exonic variants in individuals with and without PD, to investigate the role of the variants in PD susceptibility. METHODS: LRRK2 was genotyped in patients with PD and controls from three series (white, Asian, and Arab-Berber) from sites participating in the Genetic Epidemiology of Parkinson's Disease Consortium. Genotyping was done for exonic variants of LRRK2 that were identified through searches of literature and the personal communications of consortium members. Associations with PD were assessed by use of logistic regression models. For variants that had a minor allele frequency of 0·5% or greater, single variant associations were assessed, whereas for rarer variants information was collapsed across variants. FINDINGS: 121 exonic LRRK2 variants were assessed in 15â540 individuals: 6995 white patients with PD and 5595 controls, 1376 Asian patients and 962 controls, and 240 Arab-Berber patients and 372 controls. After exclusion of carriers of known pathogenic mutations, new independent risk associations were identified for polymorphic variants in white individuals (M1646T, odds ratio 1·43, 95% CI 1·15-1·78; p=0·0012) and Asian individuals (A419V, 2·27, 1·35-3·83; p=0·0011). A protective haplotype (N551K-R1398H-K1423K) was noted at a frequency greater than 5% in the white and Asian series, with a similar finding in the Arab-Berber series (combined odds ratio 0·82, 0·72-0·94; p=0·0043). Of the two previously reported Asian risk variants, G2385R was associated with disease (1·73, 1·20-2·49; p=0·0026), but no association was noted for R1628P (0·62, 0·36-1·07; p=0·087). In the Arab-Berber series, Y2189C showed potential evidence of risk association with PD (4·48, 1·33-15·09; p=0·012). INTERPRETATION: The results for LRRK2 show that several rare and common genetic variants in the same gene can have independent effects on disease risk. LRRK2, and the pathway in which it functions, is important in the cause and pathogenesis of PD in a greater proportion of patients with this disease than previously believed. These results will help discriminate those patients who will benefit most from therapies targeted at LRRK2 pathogenic activity. FUNDING: Michael J Fox Foundation and National Institutes of Health.