The role of single nucleotide variant rs3819817 of the Histidine Ammonia-Lyase gene and 25-Hydroxyvitamin D on bone mineral density, adiposity markers, and skin pigmentation, in Mexican population.

PURPOSE: Vitamin D (VD) deficiency and osteoporosis have become a global public health problem. A variant in the Histidine Ammonia-Lyase (HAL) gene has been associated with VD levels and bone mineral density (BMD). However, whether this variant has an influence on VD levels and BMD in Mexican adults remain unclear. METHODS: This cross-sectional analysis included 1,905 adults participating in the Health Worker Cohort Study and 164 indigenous postmenopausal women from the Metabolic Analysis in an Indigenous Sample (MAIS) cohort. The rs3819817 variant was genotyped by TaqMan probe assay. Total 25 hydroxyvitamin D levels were measured by DiaSorin Liaison. BMD at the different sites was assessed through dual-energy X-ray absorptiometry. Linear and logistic regression models were performed to evaluate the associations of interest. RESULTS: The prevalence of VD deficiency was 41%, showing differences between sexes. Obesity and skin pigmentation were associated with lower levels of VD in males and females. rs3819817-T allele was associated with low levels of 25-hydroxyvitamin D, VD deficiency, and hip and femoral neck BMD values (g/cm2). We found two interactions with VD levels, one between adiposity and rs3819817-T allele (P = 0.017) and another between skin pigmentation and rs3819817-T allele (P = 0.019). In indigenous postmenopausal women, we observed higher VD levels in the southern region compared to the northern region (P < 0.001); however, we did not observe differences by genotype. CONCLUSION: Our findings confirm that the genetic variant rs3819817 has an essential function in VD levels and BMD and suggests a role in skin pigmentation in the Mexican population.

PPARα polymorphisms association with total cholesterol and LDL-C levels in a Mexican population.

OBJECTIVE: Peroxisome proliferator-activated receptor alpha (PPARα) is a nuclear transcription factor with a role in gene expression changes associated to lipid metabolism. PPARα polymorphic variants have been previously correlated to serum lipid profile but in Mexico, there is no previous report about that association. For this reason, the aim of this study was to investigate the relationship between PPARα polymorphic variants and lipids level in serum in a Mexican population. PATIENTS AND METHODS: Two-hundred and forty women from the Northeast region of Mexico were included in the study. Anthropometric characteristics and serum lipid profile (such as triglycerides, total cholesterol, LDL cholesterol and HDL cholesterol) were evaluated. Genomic DNA extraction and purification were made from blood samples. Real-time PCR and TaqMan probes were used for genotyping of rs1800206 and rs4253778 single nucleotide polymorphisms (SNPs). RESULTS: Linear regression analysis (adjusted by age and body mass index (BMI)) showed a significant statistical association of rs4253778 with total cholesterol (p=0.034) and LDL cholesterol (p=0.037). Any significant association was found between rs1800206 and lipid levels. CONCLUSIONS: These results suggested that rs4253778 (C allele) is associated with high levels of total cholesterol and LDL in a Mexican women population.

The BDNF rs7934165 polymorphism is a biomarker of central obesity and cardiometabolic risk in Mexican women.

OBJECTIVE: Brain-derived neurotrophic factor (BDNF) is a cornerstone in the hypothalamic regulation of food intake and energy homeostasis. Polymorphisms in the BDNF gene may thus contribute to obesity traits. The aim of this investigation was to analyze the association of rs6265 and rs7934165 BDNF polymorphisms in women from Northeast Mexico classified as obese or overweight using their BMI and waist-to-height ratio (WHtR). PATIENTS AND METHODS: A total of 296 women were enrolled and further divided into normal weight and obese overweight groups according to their BMI status and WHtR classifications, which were low and high at < 0.50 and ≥ 0.50, respectively. Genotyping of BDNF rs6265 and rs7934165 polymorphisms was performed using a TaqMan assay. Distinct anthropometric, biochemical, clinical, and dietary parameters were obtained and used as covariates in the statistical analyses. RESULTS: The rs6265-G allele and its homozygote state (GG) were the most prominent without statistically significant differences between groups (p = 0.412). The study of rs7934165 with BMI showed marginal associations. Moreover, the rs7934165-AA genotype was more frequent among individuals with a high WHtR than those with a low WHtR (43.4 vs. 25.2%, p = 0.01). This association was maintained after adjustments for age and caloric intake through logistic regression analysis (OR = 2.20, 95% CI = 1.15-4.18, p = 0.016). CONCLUSIONS: The present study indicates that the BDNF-rs7934165-AA genotype is associated with a higher WHtR which is related to central obesity and its comorbidities. This suggests that this SNP could act as a potential biomarker for central obesity and cardiometabolic risk.

Association between vitamin D deficiency and common variants of Vitamin D binding protein gene among Mexican Mestizo and indigenous postmenopausal women.

PURPOSE: Vitamin D deficiency (VDD) and polymorphisms in the group-specific component (GC) gene are known to be associated in different populations. However, the effects of such genetic variants may vary across different populations. Thus, the objective of this study was to estimate the association between Vitamin D-Binding Protein (VDBP) haplotypes and VDD in mestizo postmenopausal women and Mexican Amerindian ethnic groups. METHODS: This was a cross-sectional study of 726 postmenopausal Mexican women from the Health Workers Cohort Study (HWCS) and 166 postmenopausal women from the Metabolic Analysis in an Indigenous Sample (MAIS) cohort in Mexico. GC polymorphisms (rs7045 and rs4588) were analyzed by TaqMan probes. Serum 25-hydroxyvitamin D [25(OH)D] levels were measured by Chemiluminescent Microparticle Immuno Assay. RESULTS: The prevalence of VDD serum 25(OH)D < 20 ng/mL was 43.7% in mestizo women and 44.6% in indigenous women. In HWCS, the single nucleotide polymorphisms (SNPs) rs7041 and rs4588 were associated with VDD. In addition, women from the HWCS, carrying the haplotypes GC2/2 and GC1f/2 had higher odds of VDD (OR = 2.83, 95% CI 1.14, 7.02; and OR = 2.30, 95% CI 1.40, 3.78, respectively) compared to women with haplotype 1f/1 s. These associations were not statistically significant in the MAIS cohort. CONCLUSIONS: Our results show genetic association of the analyzed SNPs and related haplotypes, on the GC gene, with VDD in mestizo Mexican postmenopausal women. Moreover, a high prevalence of VDD with high genetic variability within the country was observed. Our results support the need for national policies for preventing VDD.

COL1A1, CCDC170, and ESR1 single nucleotide polymorphisms associated with distal radius fracture in postmenopausal Mexican women.

Objective: The aim of this study was to analyze the genetic association of five ESR1 single nucleotide polymorphisms (SNPs) (rs3020331, rs851982, rs1999805, rs2234693, rs3020404), four COL1A1 SNPs (rs1800012, rs2075555, rs2412298, rs1107946), and two SNPs on the CCDC170 gene (rs9479055, rs4870044) with distal radius fracture (DRF) in a group of postmenopausal Mexican women.Methods: A case-control study was conducted. Cases (n = 182) were women above the age of 38 years with low-energy DRF, and controls (n = 201) were women without. Analysis was done through real-time polymerase chain reaction. Frequencies and Hardy-Weinberg equilibrium were calculated. A multivariate analysis including bone mass index, age, menarche, and menopause as covariables was carried out. Finally, haplotype and linkage disequilibrium (LD) analyses were performed.Results:COL1A1 rs1107946 was strongly associated with DRF. Both CCDC170 SNPs showed strong association with DRF. For the ESR1 gene, four SNPs (rs2234693, 3020404, rs3020331, and rs851982) showed very strong association with DRF. Additionally, the region between the latter two showed strong LD.Conclusions: A strong association of DRF with variants in these genes was found, including haplotypes and a region with strong LD on ESR1. The results suggest that these SNPs could be useful to detect the population at risk of presenting DRF among Mexican perimenopausal women.

Association of RMND1/CCDC170-ESR1 single nucleotide polymorphisms with hip fracture and osteoporosis in postmenopausal women.

OBJECTIVE: This study aimed to investigate the association of seven single nucleotide polymorphisms (SNPs) on the RMND1, CCDC170, and ESR1 genes with osteoporosis or hip fracture in a postmenopausal Mexican population. METHODS: We included a group of 400 postmenopausal women from the Health Workers Cohort Study from the Mexican Institute of Social Security. As a replication sample, we recruited 423 postmenopausal women from the National Institute of Rehabilitation. Demographic data were collected through a structured questionnaire. Bone mineral density was assessed using dual X-ray absorptiometry. Individuals were classified as normal, osteopenia, osteoporosis, and fracture, according to World Health Organization criteria. Genotyping was performed using predesigned TaqMan Probes. Linear regression analysis was used to investigate association. RESULTS: All of the analyzed SNPs showed association with at least one of the phenotypes of the study groups. In addition, we observed a region with linkage disequilibrium within the ESR1 gene in all groups. CONCLUSION: This study shows that an association of the SNPs can exist with osteopenia, osteoporosis, or fragility fracture. Our results agree with data published elsewhere, supporting the potential of these loci for the identification of the population at risk. However, additional studies are required to determine the extent of this association for other geographic regions of Mexico.

The anti-estrogenic activity of indole-3-carbinol in neonatal rat osteoblasts is associated with the estrogen receptor antagonist 2-hydroxyestradiol.

PURPOSE: To gain new insight into the roles of cruciferous vegetable-derived bioactive phytochemicals in bone cells, we investigated the effects of indole-3-carbinol (I3C) on cell proliferation and differentiation in estradiol (E2)-exposed calvarial osteoblasts that were obtained from neonatal rats. METHODS: Osteoblast activity was assessed by analyzing cellular DNA, cell-associated osteocalcin (OC) levels and alkaline phosphatase (AP) activity. We also examined [(3)H]-estrone (E1) metabolism and estrogen-agonistic and estrogen-antagonistic activities of 2-hydroxy (OH) E1 and 2-OHE2 and their capacity to displace [(3)H]-E2 at ER binding sites using competition studies. RESULTS: I3C did not affect on cellular DNA, OC levels or AP activity. However, I3C completely inhibited E2-induced increases in cell proliferation and differentiation in neonatal rat osteoblasts. Metabolic studies demonstrated that I3C promoted the conversion of [(3)H]-E1 to 2-OHE1 and 2-OHE2 and those higher rates of conversion (twofold-threefold) were archived when a higher dose of I3C was applied. Proliferation and differentiation studies showed that 2-OHE2 but not 2-OHE1 inhibited E2-induced increases in cell proliferation and differentiation via an ER-mediated mechanism. Likewise, Esr1 was expressed at high level than Esr2. 2-OHE1 showed no activity or affinity for ER. CONCLUSIONS: This study is the first to show that a bioactive compound derived from cruciferous vegetables, I3C, abolishes the E2-mediated stimulation of cell activities including, proliferation and differentiation, in rat osteoblasts and increases the 2-hydroxylation of E1, resulting in the formation of inactive and anti-estrogenic metabolites. These results suggest that in neonatal rat osteoblasts, the anti-estrogenic effect of I3C is mediated by 2-OHE2 through ER-α.

Juvenile rheumatoid arthritis and asthma, but not childhood-onset systemic lupus erythematosus are associated with FCRL3 polymorphisms in Mexicans.

A regulatory single nucleotide polymorphism located in the 5' region (-169T/C) of the Fc receptor-like 3 (FCRL3_3) gene has been associated with both susceptibility and protection in immune diseases. This case-control study aimed to evaluate the association between FCRL3 polymorphisms and juvenile rheumatoid arthritis (JRA), asthma, and childhood-onset systemic lupus erythematosus (SLE) in a Mexican population. We performed PCR-based genotyping to identify four FCRL3 single nucleotide polymorphisms (FCRL3_3 to FCRL3_6) in patients with JRA (n=202), asthma (n=239), or childhood-onset SLE (n=377), and healthy controls (n=400). The case-control analysis showed a male-gender dependent association between the FCRL3_3C, FCRL3_5C, and FCRL3_6A alleles and either JRA (OR=0.57, p=0.003; OR=0.55, p=0.002; OR=0.53, p=0.0007, respectively) or asthma (OR=0.72, p=0.04; OR=0.74, p=0.05; OR=0.70, p=0.02, respectively). As expected, minor alleles of these SNPs with the CGCA haplotype were also significantly associated with JRA (OR=0.35, p=0.00005) and asthma (OR=0.61, p=0.007). We found no association between FCRL3 SNPs or haplotypes and childhood-onset SLE. These results supported the notion that FCRL3 is involved in the etiology of several immune diseases. Our results also suggested that SNPs located in the FCRL3 gene were protective against JRA and asthma in male Mexican patients.

MiR-146a polymorphism is associated with asthma but not with systemic lupus erythematosus and juvenile rheumatoid arthritis in Mexican patients.

Extensive research has shown that aberrant expression of microRNAs (miRNAs) plays an important role in innate and adaptive immune responses. The rs2910164 polymorphism has been identified as a functional variant, which affects the transcription and expression level of miR-146a and, thereby, contributes to the pathogenesis of several inflammatory and autoimmune diseases. To investigate whether the rs2910164 G/C polymorphism was associated with asthma, systemic lupus erythematosus (SLE) or juvenile rheumatoid arthritis (JRA), we performed an association study in a pediatric Mexican cohort. We included 979 pediatric patients (asthma: 402, SLE: 367 and JRA: 210) and 531 control subjects without inflammatory or immune diseases. Genotyping was performed using the 5' exonuclease technique. The genotype distribution of the rs2910164 polymorphism was in Hardy-Weinberg equilibrium in each group. No significant differences were detected in the distribution of this polymorphism between cases and controls (P = 0.108, 0.609 and 0.553 for subjects with asthma, JRA and SLE, respectively). However, stratification by gender showed a statistically significant difference between asthmatic and control females, where the C allele was significantly associated with protection to asthma (odds ratio = 0.694, 95% confidence interval 0.519-0.929, P = 0.0138). Our results provide evidence that rs2910164 may play a role in the susceptibility to childhood-onset asthma, but not SLE or JRA in Mexicans. Further association studies may contribute to determining the role of miR-146a single-nucleotide polymorphisms in immune-mediated diseases.

The NRF2 gene variant, -653G/A, is associated with nephritis in childhood-onset systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an autoimmune disease associated with oxidative stress and characterized by chronic inflammation. Kidney malfunction, an aggressive characteristic of this disease, is not present in all affected individuals. The Nrf2-Keap1 pathway is important in protecting against oxidative stress and inflammation. Mouse models and genome-wide scans have suggested NRF2 (Nuclear factor (erythroid-derived 2)-like 2) as a candidate gene for susceptibility to SLE. We therefore investigated whether NRF2 polymorphisms are associated with childhood-onset SLE in a Mexican Mestizo population. Two single nucleotide polymorphisms (SNPs) were genotyped by TaqMan((R)) assays in 362 patients with childhood-onset SLE and 379 controls. We found no significant association between susceptibility to SLE and NRF2 polymorphisms. However, after population stratification by gender, the heterozygous genotype of the -653G/A SNP was significantly associated with nephritis in females only [OR = 1.81, CI (1.04-3.12), p = 0.032]. This association was stronger in females affected with severe nephritis [classes IV-VI; OR = 2.16, CI (1.12-4.15), p = 0.019]. Our results suggest that NRF2 is not associated with susceptibility to childhood-onset SLE, but it could confer a risk for developing kidney malfunction in SLE-affected individuals.

BCR-ABL, ETV6-RUNX1 and E2A-PBX1: prevalence of the most common acute lymphoblastic leukemia fusion genes in Mexican patients.

This study was conducted to determine the frequency of the most common fusion genes in Mexican pediatric patients with acute lymphoblastic leukemia (ALL). Molecular analysis using RT-PCR was carried out in 53-blood samples: 52 patients with de novo ALL and one with relapsed ALL. The ETV6-RUNX1 fusion was found in 7 cases (13.5%), BCR-ABL fusion was detected in 2 cases (3.8%), and 6 patients (11.5%) expressed the chimeric gene E2A-PBX1. The prevalence of E2A-PBX1 is one of the highest that has been described thus far in childhood ALL. Furthermore, we detected both the BCR-ABL, and E2A-PBX1 fusion in the relapsed patient. With regards to the immunophenotype, ETV6-RUNX1 was expressed in both pre-B and T-cell cases, while the presence of E2A-PBX1 and BCR-ABL was associated with the pre-B ALL phenotype. The prevalence of E2A-PBX1 in Mexican pediatric cases supports the existence of ethnic differences in the frequency of molecular markers of ALL.

Association analysis of the PTPN22 gene in childhood-onset systemic lupus erythematosus in Mexican population.

Several studies have identified a functional single nucleotide polymorphism 1858C/T in the PTPN22 gene to be associated with several autoimmune diseases. Association studies of this polymorphism with familial and sporadic systemic lupus erythematosus (SLE) have shown some discrepancies. To our knowledge, this is the first study that includes only pediatric-onset SLE patients. We performed a case-control association study in 250 unrelated Mexican patients with childhood-onset SLE consisting of 228 cases with sporadic SLE and 22 cases with familial SLE and 355 healthy controls. We observed a statistically significant difference in the frequency of the PTPN22 1858T allele between SLE patients (3.4%) and healthy controls (1.1%) (P=0.0062, odds ratio (OR) 3.09 (95% confidence interval 1.32-7.21)). The association was also observed when only sporadic cases were analyzed (OR=3.19). Our results support the association of the PTPN22 1858T allele with sporadic childhood-onset SLE in Mexican population.