1.
The association between the methionine/valine (M/V) polymorphism (rs1799990) in the PRNP gene and the risk of Alzheimer disease: an update by meta-analysis.
He, J, Li, X, Yang, J, Huang, J, Fu, X, Zhang, Y, Fan, H
Journal of the neurological sciences. 2013;(1-2):89-95
Abstract
BACKGROUND The M/V polymorphism in the PRNP gene has been extensively examined for the association to the risk of Alzheimer disease (AD); however, results from different studies have been inconsistent. The aim of this study is to evaluate the association between the M/V polymorphism in the PRNP gene and the risk of AD. METHODS A meta-analysis was carried out to analyze the association between the M/V polymorphism in the PRNP gene and the risk of AD. RESULTS A total of 4228 cases and 4324 controls in 16 case-control studies were included in the meta-analysis. The results indicated that the variant V allele carriers (VV+MV) had a 13% decreased risk of AD, when compared with the homozygote MM (VV+MV vs. MM: OR=0.87, 95% CI=0.79-0.96, P=0.004). In the subgroup analysis by ethnicity, significant decreased risks of AD were found in the Caucasian V allele carriers (OR=0.85, 95% CI=0.77-0.94, P=0.002), but not in Asian V allele carriers (OR=1.11, 95% CI=0.78-1.57, P=0.57). In the subgroup analysis by age of onset, significant decreased risks of AD were associated with V allele carriers in late-onset Alzheimer disease (OR=0.76, 95% CI=0.62-0.93, P=0.007) but not in early-onset Alzheimer disease (OR=0.86, 95% CI=0.70-1.06, P=0.17). CONCLUSIONS Our results suggest that the M/V polymorphism in the PRNP gene contributes to the susceptibility of Alzheimer disease.
2.
Polymorphisms in the vitamin D receptor gene and multiple sclerosis risk: a meta-analysis of case-control studies.
Huang, J, Xie, ZF
Journal of the neurological sciences. 2012;(1-2):79-85
Abstract
BACKGROUND The vitamin D receptor (VDR) polymorphisms have been reported to be associated with multiple sclerosis (MS), however, evidence remains conflicting. A meta-analysis was conducted to investigate this association. METHODS We searched Pubmed, Medline and Embase databases for case-control studies evaluating the association between the VDR Apa-I, Bsm-I, Fok-I, Taq-I polymorphisms and MS risk. Data were extracted using standardized forms and odds ratios (OR) with 95% confidence intervals (CI) were calculated. RESULTS 11 case-control studies involving a total of 2599 cases and 2816 controls were included in this meta-analysis. Available data did not suggest an association between any of the VDR polymorphisms and the risk for MS. For Taq-I, which is the most investigated VDR polymorphism with 8 studies (2472 cases and 2446 controls), the combined OR was 1.12 (95% CI: 1.00-1.26) for the dominant model (tt+Tt vs. TT), 1.03(95% CI: 0.88-1.20) for the recessive model (tt vs. Tt+TT), and 1.04 (95% CI: 0.78-1.38) for the homozygote model (tt vs. TT). ORs for other VDR polymorphisms were similar. CONCLUSION The VDR Apa-I, Bsm-I, Fok-I and Taq-I polymorphisms are not associated with MS risk.