Variants in toll-like receptors 2 and 9 influence susceptibility to pulmonary tuberculosis in Caucasians, African-Americans, and West Africans

Tuberculosis (TB) is a global public health problem and a source of preventable deaths each year, with 8.8 million new cases of TB and 1.6 million deaths worldwide in 2005. Approximately, 10% of infected individuals develop pulmonary or extrapulmonary TB, suggesting that host defense factors influence development of active disease. Toll-like receptor’ (TLR) polymorphisms have been associated with regulation of TLR expression and development of active TB. In the present study, 71 polymorphisms in TLR1, TLR2, TLR4, TLR6, and TLR9 were examined from 474 (295 cases and 179 controls) African-Americans, 381 (237 cases and 144 controls) Caucasians, and from 667 (321 cases and 346 controls) Africans from Guinea-Bissau for association with pulmonary TB using generalized estimating equations and logistic regression. Statistically significant associations were observed across populations at TLR9 and TLR2. The strongest evidence for association came at an insertion (I)/deletion (D) polymorphism (?196 to ?174) in TLR2 that associated with TB in both Caucasians (II vs. ID&DD, OR = 0.41 [95% CI 0.24–0.68], p = 0.0007) and Africans (II vs. ID&DD, OR = 0.70 [95% CI 0.51–0.95], p = 0.023). Our findings in three independent population samples indicate that variations in TLR2 and TLR9 might play important roles in determining susceptibility to TB.     

Identification of genetic associations of SP110/MYBBP1A/RELA with pulmonary tuberculosis in the Chinese Han population

Genetic factors play important roles in the development of tuberculosis (TB). SP110 is a promising candidate target for controlling TB infections. However, several studies associating SP110 single nucleotide polymorphisms (SNPs) with TB have yielded conflicting results. This may be partly resolved by studying other genes associated with SP110, such as MYBBP1A and RELA. Here, we genotyped 6 SP110 SNPs, 8 MYBBP1A SNPs and 5 RELA SNPs in 702 Chinese pulmonary TB patients and 425 healthy subjects using MassARRAY and SNaPshot methods. Using SNP-based analysis with Bonferroni correction, rs3809849 in MYBBP1A [Pcorrected (cor) = 0.0038] and rs9061 in SP110 (Pcor = 0.019) were found to be significantly associated with TB. Furthermore, meta-analysis of rs9061 in East Asian populations showed that the rs9061 T allele conferred significant risk for TB [P = 0.002, pooled odds ratio (OR), 1.24, 95 % confidence interval (CI) = 1.08–1.43]. The MYBBP1A GTCTTGGG haplotype and haplotypes CGACCG/TGATTG within SP110 were found to be markedly and significantly associated with TB (P = 2.00E?06, 5.00E?6 and 2.59E?4, respectively). Gene-based analysis also demonstrated that SP110 and MYBBP1A were each associated with TB (Pcor = 0.011 and 0.035, respectively). The logistic regression analysis results supported interactions between SP110 and MYBBP1A, indicating that subjects carrying a GC/CC genotype in MYBBP1A and CC genotype in SP110 possessed the high risk of developing TB (P = 1.74E?12). Our study suggests that a combination of SP110 and MYBBP1A gene polymorphisms may serve as a novel marker for identifying the risk of developing TB in the Chinese Han population.     

DNMT1, DNMT3A and DNMT3B gene variants in relation to ovarian cancer risk in the Polish population

Studies have demonstrated that changes in DNA methylation of cancer related genes can be an elementary process accounting for ovarian tumorigenesis. Therefore, we evaluated the possible association of single nucleotide polymorphisms (SNPs) of DNA methyltransferases (DNMTs) genes, including DNMT1, DNMT3B, and DNMT3A, with ovarian cancer development in the Polish population. Using PCR–RFLP and HRM analyses, we studied the prevalence of the DNMT1 rs8101626, rs2228611 and rs759920, DNMT3A rs2289195, 7590760, rs13401241, rs749131 and rs1550117, and DNMT3B rs1569686, rs2424913 and rs2424932 SNPs in patients with ovarian cancer (n = 159) and controls (n = 180). The lowest p values of the trend test were observed for the DNMT1 rs2228611 and rs759920 SNPs in patients with ovarian cancer (p _trend = 0.0118 and p _trend = 0.0173, respectively). Moreover, we observed, in the recessive inheritance model, that the DNMT1 rs2228611 and rs759920 SNPs are associated with an increased risk of ovarian cancer development [OR 1.836 (1.143–2.949), p = 0.0114, p _corr = 0.0342, and OR 1.932 (1.185–3.152), p = 0.0078, p _cor=0.0234, respectively]. However, none of other nine studied SNPs displayed significant contribution to the development of ovarian cancer. Furthermore, haplotype and multifactor dimensionality reduction analysis of the studied DNMT1, DNMT3B, and DNMT3A polymorphisms did not reveal either SNP combinations or gene interactions to be associated with the risk of ovarian cancer development. Our results may suggest that DNMT1 variants may be risk factors of ovarian cancer.     

Impact of cytokine and cytokine receptor gene polymorphisms on cellular immunity after smallpox vaccination

We explored associations between SNPs in cytokine/cytokine receptor genes and cellular immunity in subjects following primary smallpox vaccination. We also analyzed the genotype–phenotype associations discovered in the Caucasian subjects among a cohort of African-Americans. In Caucasians we found 277 associations (p < 0.05) between gene SNPs and inter-individual variations in IFN-α, IL-12p40, IL-1β, IL-2, and TNF-α secretion levels. A collection of SNPs in the IL1RN, IL2RB, IL4R, IL6, IL10RB, IL12A, and IL12RB2 genes had consistent associations among both Caucasians and African-Americans. A regulatory SNP (rs452204) in the IL1RN gene was significantly associated with higher levels of IL-2 secretion in an allele dose-dependent manner in both race groups (p = 0.05 for Caucasians and p = 0.002 for African-Americans). IL12RB2 polymorphism rs3790567 was associated with a dose-related decrease in IL-1β secretion (p = 0.009 for Caucasians and p = 0.01 for African-Americans). Our results demonstrate that variations in smallpox vaccine-induced cytokine responses are modulated by genetic polymorphisms in cytokine and cytokine receptor genes.     

Evidence of statistical epistasis between DISC1, CIT and NDEL1 impacting risk for schizophrenia: biological validation with functional neuroimaging

The etiology of schizophrenia likely involves genetic interactions. DISC1, a promising candidate susceptibility gene, encodes a protein which interacts with many other proteins, including CIT, NDEL1, NDE1, FEZ1 and PAFAH1B1, some of which also have been associated with psychosis. We tested for epistasis between these genes in a schizophrenia case–control study using machine learning algorithms (MLAs: random forest, generalized boosted regression and Monte Carlo logic regression). Convergence of MLAs revealed a subset of seven SNPs that were subjected to 2-SNP interaction modeling using likelihood ratio tests for nested unconditional logistic regression models. Of the ⁷C₂ = 21 interactions, four were significant at the α = 0.05 level: DISC1 rs1411771–CIT rs10744743 OR = 3.07 (1.37, 6.98) p = 0.007; CIT rs3847960–CIT rs203332 OR = 2.90 (1.45, 5.79) p = 0.003; CIT rs3847960–CIT rs440299 OR = 2.16 (1.04, 4.46) p = 0.038; one survived Bonferroni correction (NDEL1 rs4791707–CIT rs10744743 OR = 4.44 (2.22, 8.88) p = 0.00013). Three of four interactions were validated via functional magnetic resonance imaging (fMRI) in an independent sample of healthy controls; risk associated alleles at both SNPs predicted prefrontal cortical inefficiency during the N-back task, a schizophrenia-linked intermediate biological phenotype: rs3847960–rs440299; rs1411771–rs10744743, rs4791707–rs10744743 (SPM5 p < 0.05, corrected), although we were unable to statistically replicate the interactions in other clinical samples. Interestingly, the CIT SNPs are proximal to exons that encode the DISC1 interaction domain. In addition, the 3′ UTR DISC1 rs1411771 is predicted to be an exonic splicing enhancer and the NDEL1 SNP is ~3,000 bp from the exon encoding the region of NDEL1 that interacts with the DISC1 protein, giving a plausible biological basis for epistasis signals validated by fMRI.     

A non-synonymous SNP in the NOS2 associated with septic shock in patients with sepsis in Chinese populations

Sepsis represents a systemic inflammatory response to infection and its sequelae include severe sepsis, septic shock, multiple organ dysfunction syndrome (MODS) and death. Studies in mice and humans indicate that the inducible nitric oxide synthase (iNOS, NOS2) plays an important role in the development of sepsis and its sequelae. It was reported that several single nucleotide polymorphisms (SNPs) within NOS2 could influence the production or activity of NOS2. In this study, we assessed whether SNPs within NOS2 gene were associated with severity of sepsis in Chinese populations. A case–control study was conducted, which included 299 and 280 unrelated patients with sepsis recruited from Liaoning and Jiangsu provinces in China, respectively. Six SNPs within NOS2 were genotyped using Sequenom MassARRAY system. The associations between the SNPs and risk of sepsis complications were estimated by a binary logistic regression model adjusted for confounding factors. Functional assay was performed to assess the biological significance. The GA + AA genotype of a non-synonymous SNP in the exon 16 of NOS2 (rs2297518: G>A) was significantly associated with increased susceptibility to septic shock compared with GG genotype in Liaoning population (OR = 3.29, 95 % CI = 1.40–7.72, P = 0.0047). This association was confirmed in the Jiangsu population (OR = 3.49, 95 % CI = 1.57–7.79, P = 0.0019). Furthermore, the functional assay performed in the immortalized lymphocyte cell lines indicated that the at-risk GA genotype had a tendency of higher NOS2 activity than the GG genotype (P = 0.32). Our findings suggest that the NOS2 rs2297518 may play a role in mediating the susceptibility to septic shock in patients with sepsis in Chinese populations.     

Association of polymorphisms in the Chr18q11.2 locus with tuberculosis in Chinese population

A GWAS study has reported that two single nucleotide polymorphisms (SNPs) were associated with predisposition to tuberculosis (TB) in African populations. These two loci represented the long-waited GWAS hits for TB susceptibility. To determine whether these two SNPs are associated with TB in Chinese population, we attempted an replication in a cohort of over one thousand Chinese TB patients and 1,280 healthy controls using melting temperature shift allele-specific genotyping analysis. We found that only SNP rs4331426 was significantly associated with TB in Chinese population (p = 0.011). However, the effect was opposite. The G allele of the SNP in Chinese population is a protective allele (OR = 0.62, 95 % CI 0.44–0.87), while it was the risk allele for African population (OR = 1.19, 95 % CI 1.12–1.26). No significance was found for SNP rs2335704. The results provided an independent support for a role in susceptibility to TB for SNP rs4331426. However, it also indicated that direct predisposition element to TB and the association effects may vary across ethnic groups.     

Association of common WRAP 53 variant with ovarian cancer risk in the Polish population

Among many alterations within the TP53 gene the rs1042522 (C72G, p.Pro72Arg) has been associated with numerous cancers , however the results differ between populations for opposite Pro or Arg alleles. Similar thus inconclusive results are observed in ovarian cancer, which may suggest that the rs1042522 does not influence ovarian carcinogensis directly, but might be linked to another pathogenic alteration. WRAP53 which overlaps the TP53 is required to maintain normal levels of p53 upon DNA damage, but also when altered may independently increase the risk of cancer. To evaluate the association between three SNPs located in WRAP53–TP53 region: rs1042522, rs2287497, rs2287498 and ovarian cancer risk in Polish population we genotyped 626 cases and 1,045 healthy controls. Our results provide the evidence for an association between studied SNPs and a risk of invasive ovarian cancer in Poland. We found that CC homozygotes in rs1042522 were more frequent in cancers when compared to controls (OR = 1.46, p = 0.03). Similarly in WRAP53 both TT homozygotes in rs2287497 (OR = 1.95, p = 0.03) and AA homozygotes in rs2287498 (OR = 2.65, p = 0,01) were more frequent among cases than healthy individuals. There is also a suggestive evidence that specific homozygosity of studied SNPs in TP53–WRAP53 region is significantly overrepresented in ovarian cancer patients. In conclusion SNPs in WRAP53 (rs2287497 and rs2287498) have stronger association with an ovarian cancer risk than rs1042522 in TP53.     

Chromosome 9p21 rs10757278 polymorphism is associated with the risk of metabolic syndrome

Metabolic syndrome (MetS) is a common multifactorial disorder that involves abdominal obesity, dyslipidemia, hypertension, and hyperglycemia. Genome-wide association studies have identified a major risk locus for coronary artery disease and myocardial infarction on chromosome 9p21. Here, we examined the frequency of single nucleotide polymorphisms (SNPs) on chromosome 9p21 in a sample of Turkish patients with MetS and further investigated the correlation between regional SNPs, haplotypes, and MetS. The real-time polymerase chain reaction (RT-PCR) was used to analyze 4 SNPs (rs10757274 A/G, rs2383207 A/G, rs10757278 A/G, rs1333049 C/G) in 291 MetS patients and 247 controls. Analysis of 4 SNPs revealed a significant difference in the genotype distribution for rs2383207, rs10757278, and rs1333049 between MetS patients and controls (p = 0.041, p = 0.005, p = 0.023, respectively) but not for rs10757274 (p = 0.211). MetS and control allelic frequencies for rs2383207, rs10757278, and rs1333049 were statistically different (p < 0.05). The rs2383207 AG variant, was identified as a MetS risk factor (p = 0.012, OR = 33.271; 95 % CI: 2.193–504.805) and the AA haplotype in block 1 and the GC, AG haplotypes in block 2 were associated with MetS (χ ² = 3.875, p = 0.049; χ ² = 9.334, p = 0.0022; χ ² = 9.134, p = 0.0025, respectively). In this study, we found that chromosome 9p21 SNP rs10757278 and related haplotypes correlate with MetS risk. This is the first report showing an association between a 9p21 variant and MetS and suggests that rs10757278 polymorphism may confer increased risk for disease.     

Polymorphism of cytokine and innate immunity genes associated with bovine brucellosis in cattle

Genetic susceptibility to brucellosis is multifactorial, and it is known that impairment of the immune system could contribute to risk for getting brucellosis. The aim of the study was to find association of bovine brucellosis with 20 SNPs pertaining to bovine cytokine (IFNG, IFNGR1, IFNGR2, TNFA) and innate immunity (SLC11A1, TLR1, TLR4, and TLR9) genes using PCR-RFLP genotyping technique and it was observed that SLC11A1 (+1066 C/G), TLR1 (+1446 C/A), TLR1 (+1380 G/A), TLR4 (+10 C/T) and TLR4 (+399 C/T) loci were significantly (P ≤ 0.05) associated with bovine brucellosis. The odds ratios (OR) of CG and CC genotypes versus GG genotype were 0.31 (0.12–0.82; 95 % CI) and 0.18 (0.03–1.06; 95 % CI) at SLC11A1 (+1066 C/G) locus in cases of brucellosis affected cattle. For TLR1 (+1380 G/A) locus, the OR for AG and AA genotypes versus GG genotypes were 0.15 (0.05–0.44; 95 % CI) and 0.26 (0.04–1.47; 95 % CI) which indicated that proportion of GG homozygote was significantly higher in brucellosis affected animals as compared to control. At TLR1 (+1446 C/A) locus the OR of AC genotype versus CC genotype was 0.24 (0.08–0.68; 95 % CI) which revealed that relative proportion CC genotypes was significantly higher in case population. The TLR4 (+10 C/T) locus had three genotypes (TT, CT and CC) where OR of CT and CC genotypes versus TT genotype were near to zero. The OR of CT genotypes versus CC genotypes was 8.25 (0.94–71.92; 95 % CI) at TLR4 (+399 C/T) locus and indicated that CT genotype had higher odds of bovine brucellosis than control animals.     

Toll-like receptor polymorphisms and vasculitis susceptibility: meta-analysis and systematic review

The aim of this study was to determine whether toll-like receptor (TLR) polymorphisms confers susceptibility to vasculitis. A literature search was conducted using the PubMed and Embase. A meta-analysis on the associations between the TLR4 Asp299Gly polymorphisms and vasculitis was carried out using allele contrast, dominant, and codominant models and a systematic review of other TLR polymorphisms. Fourteen studies involving 2,064 patients and 2,481 controls were included in this systematic review, which comprised nine on Behcet’s disease (BD), three on giant cell arteritis (GCA), and one on Henoch–Schenlein purpura (HSP). Meta-analysis of six studies showed a significant association between the Gly/Gly+Gly/Asp genotype of the TLR4 Asp299Gly polymorphism and vasculitis and GCA (Odds ratio [OR] = 1.368, 95 % confidence interval [CI] = 1.300–1.815, p = 0.030; OR = 1.523, 95 % CI = 1.099–2.112, p = 0.012). Under a random effects model, the adjusted ORs calculated using the trim and fill technique revealed an association between the Gly/Gly+Gly/Asp genotype of the TLR4 Asp299Gly polymorphism and vasculitis (OR = 1.544, 95 % CI = 1.091–2.185, p < 0.05). Stratification by vasculitis type using the codominant model showed the trend for the association with GCA (OR = 1.569, 95 % CI = 0.970–2.538, p = 0.066). There were three studies on the TLR2 Arg753Gln polymorphism and two on the TLR4 Thr399Ile polymorphism; no association with vasculitis was evident. Among the TLR2, TLR7, and TLR9 polymorphisms included in this review, one Asian study revealed a significant association between the TLR7 rs5743733 and rs3853839 with BD (p = 0.002, 0.036) and one Asian study showed an association of TLR9 rs352140 with BD (p = 0.009). This meta-analysis demonstrates that the TLR4 Asp299Gly polymorphism may confer susceptibility to GCA. The review of published data suggests that other TLR polymorphisms such as TLR7 and TLR9 may play a role in vasculitis.     

Genetic variants at 4q21, 4q23 and 12q24 are associated with esophageal squamous cell carcinoma risk in a Chinese population

A recently published genome-wide association study (GWAS) in European populations identified several loci at 4q21, 4q23 and 12q24 that were associated with risk of upper aerodigestive tract (UADT) cancers, including esophageal squamous cell carcinoma (ESCC). In the current study, we conducted a case–control study in a Chinese population including 2,139 ESCC cases and 2,273 controls to evaluate the associations of six reported single nucleotide polymorphisms (SNPs) (rs1494961, rs1229984, rs1789924, rs971074, rs671 and rs4767364) with risk of ESCC. We found significant association with risk of ESCC for four SNPs, including rs1494961 in HEL308 at 4q21 [odds ratio (OR) = 1.15, 95 % confidence interval (CI) = 1.05–1.26], rs1229984 in ADH1B at 4q23 (OR = 1.24, 95 % CI = 1.13–1.36) and rs1789924 near ADH1C at 4q23 (OR = 1.20, 95 % CI = 1.03-1.39), and rs671 in ALDH2 at 12q24 (OR = 0.83, 95 % CI = 0.75–0.91). Combined analysis of these four SNPs showed a significant allele-dosage effect on ESCC risk for individuals with different number of risk alleles (P trend = 2.23 × 10^?11). Compared with individuals with “0–2” risk allele, those carrying “3”, “4” or “5 or more” risk alleles had 1.42-, 1.66-, or 1.76-fold risk of ESCC, respectively. Thus, our findings indicate that rs1494961 at 4q21, rs1229984 and rs1789924 at 4q23, and rs671 at 12q24 may be used as genetic biomarkers for ESCC susceptibility in Chinese population.     

Association analyses between the genetic polymorphisms of HNF4A and FOXO1 genes and Chinese Han patients with type 2 diabetes

The hepatocyte nuclear factor 4-alpha (HNF4A) and human forkhead box O1 (FOXO1) genes have been discovered to be associated with type 2 diabetes (T2D) in different populations. This study aimed to evaluate the association between HNF4A and FOXO1 genetic polymorphisms and type 2 diabetes in the Chinese Han population. Five hundred and seventy-seven patients with type 2 diabetes and 462 normal controls were enrolled in this study. Six single-nucleotide polymorphisms (SNPs) in HNF4A and seven in FOXO1 were selected and genotyped with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) or TaqMan^® technology. Single-locus analyses indicated that the C allele of rs11574736 from HNF4A had a lower frequency in the case group compared with the control group (P = 0.005, OR = 0.74, 95% CI = 0.59–0.92). The genotype distributions of rs11574736 also differed between the two groups (P = 0.02). However, none of the FOXO1 SNPs showed any association with type 2 diabetes in the Chinese Han population. Further analysis suggested the two genes interact with each other (rs3908773/rs717247/rs6031587/rs11574736: P < 0.0001, testing accuracy = 0.55, CV consistency = 6/10). In conclusion, this study shows an association between the HNF4A gene and type 2 diabetes in the Chinese Han population. Moreover, the authors confirmed the results of previous studies for the interaction between HNF4A and FOXO1 in the pathogenesis of type 2 diabetes.     

Association, interaction, and replication analysis of genes encoding serotonin transporter and 5-HT3 receptor subunits A and B in alcohol dependence

On the basis of the converging evidence showing regulation of drinking behavior by 5-HT_3AB receptors and the serotonin transporter, we hypothesized that the interactive effects of genetic variations in the genes HTR3A, HTR3B, and SLC6A4 confer greater susceptibility to alcohol dependence (AD) than do their effects individually. We examined the associations of AD with 22 SNPs across HTR3A, HTR3B, and two functional variants in SLC6A4 in 500 AD and 280 healthy control individuals of European descent. We found that the alleles of the low-frequency SNPs rs33940208:T in HTR3A and rs2276305:A in HTR3B were inversely and nominally significantly associated with AD with odds ratio (OR) and 95 % confidence interval of 0.212 and 0.073, 0.616 (P = 0.004) and 0.261 and 0.088, 0.777 (P = 0.016), respectively. Further, our gene-by-gene interaction analysis revealed that two four-variant models that differed by only one SNP carried a risk for AD (empirical P < 1 × 10^?6 for prediction accuracy of the two models based on 10⁶ permutations). Subsequent analysis of these two interaction models revealed an OR of 2.71 and 2.80, respectively, for AD (P < 0.001) in carriers of genotype combinations 5′-HTTLPR:LL/LS(SLC6A4)–rs1042173:TT/TG(SLC6A4)–rs1176744:AC(HTR3B)–rs3782025:AG(HTR3B) and 5′-HTTLPR:LL/LS(SLC6A4)–rs10160548:GT/TT(HTR3A)–rs1176744:AC(HTR3B)–rs3782025:AG(HTR3B). Combining all five genotypes resulted in an OR of 3.095 (P = 2.0 × 10^?4) for AD. Inspired by these findings, we conducted the analysis in an independent sample, OZ-ALC-GWAS (N = 6699), obtained from the NIH dbGAP database, which confirmed the findings, not only for all three risk genotype combinations (Z = 4.384, P = 1.0 × 10^?5; Z = 3.155, P = 1.6 × 10^?3; and Z = 3.389, P = 7.0 × 10^?4, respectively), but also protective effects for rs33940208:T (χ ² = 3.316, P = 0.0686) and rs2276305:A (χ ² = 7.224, P = 0.007). These findings reveal significant interactive effects among variants in SLC6A4–HTR3A–HTR3B affecting AD. Further studies are needed to confirm these findings and characterize the molecular mechanisms underlying these effects.     

Identification of genetic variation that determines human trehalase activity and its association with type 2 diabetes

A prior linkage scan in Pima Indians identified a putative locus for type two diabetes (T2D) and body mass index (BMI) on chromosome 11q23-25. Association mapping across this region identified single nucleotide polymorphisms (SNPs) in the trehalase gene (TREH) that were associated with T2D. To assess the putative connection between trehalase activity and T2D, we performed a linkage study for trehalase activity in 570 Pima Indians who had measures of trehalase activity. Strong evidence of linkage of plasma trehalase activity (LOD = 7.0) was observed in the TREH locus. Four tag SNPs in TREH were genotyped in these subjects and plasma trehalase activity was highly associated with three SNPs: rs2276064, rs117619140 and rs558907 (p = 2.2 × 10^?11–1.4 × 10^?23), and the fourth SNP, rs10790256, was associated conditionally on these three (p = 2.9 × 10^?7). Together, the four tag SNPs explained 51 % of the variance in plasma trehalase activity and 79 % of the variance attributed to the linked locus. These four tag SNPs were further genotyped in 828 subjects used for association mapping of T2D, and rs558907 was associated with T2D (odds ratio (OR) 1.94, p = 0.002). To assess replication of the T2D association, all four tag SNPs were additionally genotyped in two non-overlapping samples of Native Americans. Rs558907 was reproducibly associated with T2D in 2,942 full-heritage Pima Indians (OR 1.27 p = 0.03) and 3,897 “mixed” heritage Native Americans (OR 1.21, p = 0.03), and the strongest evidence for association came from combining all samples (OR 1.27 p = 1.6 × 10^?4, n = 7,667). However, among 320 longitudinally studied subjects, measures of trehalase activity from a non-diabetic exam did not predict those who would eventually develop diabetes versus those who would remain non-diabetic (hazard ratio 0.94 per SD of trehalase activity, p = 0.29). We conclude that variants in TREH control trehalase activity, and although one of these variants is also reproducibly associated with T2D, it is likely that the effect of the SNP on risk of T2D occurs by a mechanism different than affecting trehalase activity. Alternatively, TREH variants may be tagging a nearby T2D locus.     

Gene-environment interactions and obesity traits among postmenopausal African-American and Hispanic women in the Women’s Health Initiative SHARe Study

Genome-wide association studies (GWAS) of obesity measures have identified associations with single nucleotide polymorphisms (SNPs). However, no large-scale evaluation of gene-environment interactions has been performed. We conducted a search of gene-environment (G × E) interactions in post-menopausal African-American and Hispanic women from the Women’s Health Initiative SNP Health Association Resource GWAS study. Single SNP linear regression on body mass index (BMI) and waist-to-hip circumference ratio (WHR) adjusted for multidimensional-scaling-derived axes of ancestry and age was run in race-stratified data with 871,512 SNPs available from African-Americans (N = 8,203) and 786,776 SNPs from Hispanics (N = 3,484). Tests of G × E interaction at all SNPs for recreational physical activity (m h/week), dietary energy intake (kcal/day), alcohol intake (categorical), cigarette smoking years, and cigarette smoking (ever vs. never) were run in African-Americans and Hispanics adjusted for ancestry and age at interview, followed by meta-analysis of G × E interaction terms. The strongest evidence for concordant G × E interactions in African-Americans and Hispanics was for smoking and marker rs10133840 (Q statistic P = 0.70, beta = ?0.01, P = 3.81 × 10^?7) with BMI as the outcome. The strongest evidence for G × E interaction within a cohort was in African-Americans with WHR as outcome for dietary energy intake and rs9557704 (SNP × kcal = ?0.04, P = 2.17 × 10^?7). No results exceeded the Bonferroni-corrected statistical significance threshold.     

Case–control association study of polymorphisms in the voltage-gated sodium channel genes SCN1A,SCN2A,SCN3A,SCN1B,and SCN2B and epilepsy

High-frequency action potentials are mediated by voltage-gated sodium channels, composed of one large α subunit and two small β subunits, encoded mainly by SCN1A, SCN2A, SCN3A, SCN1B, and SCN2B genes in the brain. These play a key role in epilepsy, with the most commonly mutated gene in epilepsy being SCN1A. We examined whether polymorphisms in the above genes affect epilepsy risk in 1,529 epilepsy patients and 1,935 controls from four ethnicities or locations: Malay, Indian, and Chinese, all from Malaysia, and Chinese from Hong Kong. Of patients, 19 % were idiopathic, 42 % symptomatic, and 40 % cryptogenic. We genotyped 43 polymorphisms: 27 in Hong Kong, 28 in Malaysia, and 12 in both locations. The strongest association with epilepsy was rs3812718, or SCN1A IVS5N+5G>A: odds ratio (OR) = 0.85 for allele G (p = 0.0009) and 0.73 for genotype GG versus AA (p = 0.003). The OR was between 0.76 and 0.87 for all ethnicities. Meta-analysis confirmed the association (OR = 0.81 and p = 0.002 for G, and OR = 0.67 and p = 0.007 for GG versus AA), which appeared particularly strong for Indians and for febrile seizures. Allele G affects splicing and speeds recovery from inactivation. Since SCN1A is preferentially expressed in inhibitory neurons, G may decrease epilepsy risk. SCN1A rs10188577 displayed OR = 1.20 for allele C (p = 0.003); SCN2A rs12467383 had OR = 1.16 for allele A (p = 0.01), and displayed linkage disequilibrium with rs2082366 (r ² = 0.67), whose genotypes tended toward association with SCN2A brain expression (p = 0.10). SCN1A rs2298771 was associated in Indians (OR = 0.56, p = 0.005) and SCN2B rs602594 with idiopathic epilepsy (OR = 0.62, p = 0.002). Therefore, sodium channel polymorphisms are associated with epilepsy.     

Association of the HTR2A gene with alcohol and heroin abuse

Positive genetic associations of rs6313 (102T/C at exon 1) and rs6311 (?1438A/G) on the 5-hydroxytryptamine (serotonin) 2A receptor gene (HTR2A or 5-HT2A) were reported for alcohol and drug abuse; however, other association studies failed to produce consistent results supporting the susceptibility of the two single nucleotide polymorphisms (SNPs). To clarify the associations of the HTR2A gene with substance use disorders, we performed a meta-analysis based on the genotypes from the available candidate gene association studies of the two SNPs with alcohol and drug abuse from multiple populations. Evidence of association was found for HTR2A rs6313 in all the combined studies (e.g., allelic P = 0.0048 and OR 0.86, 95 % CI 0.77–0.95) and also in the combined studies of alcohol dependence (abuse) (e.g., allelic P = 0.0001 and OR 0.71, 95 % CI 0.59–0.85). The same association trend was also observed in the Study of Addiction: Genetics and Environment datasets. The meta-analysis supports a contribution of the HTR2A gene to the susceptibility to substance use disorders, particularly alcohol dependence.     

IFNG polymorphisms are associated with tuberculosis in Han Chinese pediatric female population

Host genetic factors play a major role in determining differential susceptibility to human tuberculosis (TB), a re-emerging infectious disease throughout the world. Genetic variations in the IFNG gene coding for interferon gamma (IFN-γ), have been identified in TB patients. To investigate the association of the IFNG polymorphisms with TB susceptibility in Chinese pediatric population. A case–control study of 189 TB patients and 164 controls was performed using single-nucleotide polymorphism (SNP) analysis. Genomic DNA was extracted from leukocytes in peripheral blood. Three SNPs of IFNG, including ?1616C/T (rs2069705), +874A/T (rs2430561), and +3234C/T (rs2069718), were selected for genotyping and analysis. The +874A and +3234C alleles were more frequent among TB patients (P = 0.108 and P = 0.088), especially in females (both P = 0.029), although this difference was not significant since Bonferroni corrected significance threshold was 0.025 (two of three SNPs were found to be in linkage disequilibrium). More pronounced differences for the +874 and +3234 polymorphisms were found under the genotype comparison between TB cases and controls in the total population [P = 0.026 (borderline non-significance) and P = 0.020, respectively], and in the female subgroup (P = 0.020 and P = 0.020). The dominant model of inheritance was shown to be significant for +874A and +3234C alleles (both P = 0.019) in the female subgroup. The +874A and +3234C alleles were more frequently found in extrapulmonary TB patients than in controls (P = 0.039). Haplotype analysis carried out on these three SNPs showed the TTT haplotype to be more frequent in controls than in TB cases, and this difference showed a strong significance (P = 0.005). The +874A and +3234C alleles may be related to TB susceptibility in the female subgroup in the Chinese pediatric population of North China. The higher rate of +874A (known to correlate with lower IFN-γ expression) in the extrapulmonary TB subgroup suggests a sufficient IFN-γ expression to be not only an important factor for the onset of TB disease but also for limiting its dissemination to lungs.