Association of mitochondrial variants A4336G of the tRNAGln gene and 8701G/A of the MT-ATP6 gene in Mexicans Mestizos with Parkinson disease.

INTRODUCTION: Sporadic Parkinson's disease (PD) is a neurodegenerative disorder of unknown etiology. In recent years, it has been established that a genetic component underlies different forms of the disease. For instance, mitochondrial genome variants have been implicated in the pathogenesis of the PD. AIM OF THE STUDY: To determine the association of tRNA(Gln) 4336 and 8701A>G (ATP6: Thr59Ala) mitochondrial DNA polymorphisms with the presence of PD in Mexican mestizo patients. MATERIAL AND METHODS: This was a cross-sectional study in which patients were recruited from four tertiary-care level hospitals in Mexico. Genotyping was performed using real-time PCR with TaqMan genotyping assays. Genotypes were confirmed by automated sequencing. RESULTS: The 4336C allele of the tRNAGln gene was present at a low frequency, and the 8701G allele of the MT-ATP6 gene was not associated with PD. CONCLUSIONS: The 4336C variant of the tRNAGln gene was uncommon in the study population, and 8701A/G of MT-ATP6 was not associated with PD in Mexican Mestizos.

Relation of the estrogen receptor and vitamin D receptor polymorphisms with bone mineral density in postmenopausal Mexican-mestizo women.

BACKGROUND: Since osteoporosis is a complex disease characterized by low bone mineral density (BMD), which is determined by an interaction of genetics with metabolic and environmental factors, the aim of this study was to analyze the possible association among one polymorphism of VDR and two polymorphisms of ESR1; as well as their haplotypes with BMD in postmenopausal Mexican-mestizo women. METHODS: We studied 742 postmenopausal Mexican-mestizo women. A structured questionnaire for risk factors was applied and BMD was measured in the lumbar spine and total hip by dual-energy X-ray absorptiometry. DNA was obtained from blood leukocytes. One polymorphism of VDR (rs11568820) and two of ESR1 (rs2234693 and rs9340799) were studied. Real-time PCR allelic discrimination was used for genotyping. The differences between the means of the BMDs according to genotype were analyzed with covariance. Hardy-Weinberg equilibrium was tested. Pairwise linkage disequilibrium between single nucleotide polymorphisms was calculated by direct correlation r(2); haplotype analysis was conducted. RESULTS: Rs9340799 of ESR1 and one haplotype formed by the two polymorphisms of the ESR1 were significantly associated with FN-BMD variations. Moreover, analysis of the genotype of rs11568820 of VDR and the rs2234693 of ESR1 showed no significant differences with BMD variations. CONCLUSIONS: Our results showed that rs9340799 and one haplotype of ESR1 were significantly associated with BMD only at the femoral neck and this association remained after adjusting for covariates.

Risk factors and impact on bone mineral density in postmenopausal Mexican mestizo women.

OBJECTIVE: Considering that the Mexican mestizo population seems to be the result of a genetic admixture, we proposed that further research is needed to evaluate the role of ethnicity in conjunction with health-related factors to better understand ethnic differences in bone mineral density (BMD). The aim of this study was to analyze several risk factors related to the development of osteoporosis in postmenopausal Mexican mestizo women. METHODS: We included 567 postmenopausal Mexican mestizo women. A structured questionnaire for risk factors was applied and BMD was measured in total hip and lumbar spine by dual-energy x-ray absorptiometry. Nonconditional logistic regression was used to estimate crude and adjusted odds ratio. RESULTS: Using World Health Organization criteria, 28.7% of postmenopausal women had osteoporosis, 46.4% had osteopenia, and 24.9% had normal BMD. Each clinical risk factor had a different significance for osteopenia/osteoporosis; however, duration of total breast-feeding, body mass index, and number of years since menopause remained significantly associated with osteopenia/osteoporosis after bone density was added to the nonconditional model. Interestingly, extended periods of accumulated breast-feeding for 24 and 36 months were, in both cases, significantly associated with osteopenia/osteoporosis. CONCLUSIONS: Our results confirm the importance of considering the duration of breast-feeding as an important risk factor for osteopenia/osteoporosis. In addition, we find that body mass index is positively associated with BMD. Because of the heterogeneity of the Mexican mestizo population, the risk factor for osteoporosis may not be the same in different ethnic groups.