Body mass index stratified meta-analysis of genome-wide association studies of polycystic ovary syndrome in women of European ancestry.

BACKGROUND: Polycystic ovary syndrome (PCOS) is a complex multifactorial disorder with a substantial genetic component. However, the clinical manifestations of PCOS are heterogeneous with notable differences between lean and obese women, implying a different pathophysiology manifesting in differential body mass index (BMI). We performed a meta-analysis of genome-wide association study (GWAS) data from six well-characterised cohorts, using a case-control study design stratified by BMI, aiming to identify genetic variants associated with lean and overweight/obese PCOS subtypes. RESULTS: The study comprised 254,588 women (5,937 cases and 248,651 controls) from individual studies performed in Australia, Estonia, Finland, the Netherlands and United States of America, and separated according to three BMI stratifications (lean, overweight and obese). Genome-wide association analyses were performed for each stratification within each cohort, with the data for each BMI group meta-analysed using METAL software. Almost half of the total study population (47%, n = 119,584) were of lean BMI (≤ 25 kg/m2). Two genome-wide significant loci were identified for lean PCOS, led by rs12000707 within DENND1A (P = 1.55 × 10-12) and rs2228260 within XBP1 (P = 3.68 × 10-8). One additional locus, LINC02905, was highlighted as significantly associated with lean PCOS through gene-based analyses (P = 1.76 × 10-6). There were no significant loci observed for the overweight or obese sub-strata when analysed separately, however, when these strata were combined, an association signal led by rs569675099 within DENND1A reached genome-wide significance (P = 3.22 × 10-9) and a gene-based association was identified with ERBB4 (P = 1.59 × 10-6). Nineteen of 28 signals identified in previous GWAS, were replicated with consistent allelic effect in the lean stratum. There were less replicated signals in the overweight and obese groups, and only 4 SNPs were replicated in each of the three BMI strata. CONCLUSIONS: Genetic variation at the XBP1, LINC02905 and ERBB4 loci were associated with PCOS within unique BMI strata, while DENND1A demonstrated associations across multiple strata, providing evidence of both distinct and shared genetic features between lean and overweight/obese PCOS-affected women. This study demonstrated that PCOS-affected women with contrasting body weight are not only phenotypically distinct but also show variation in genetic architecture; lean PCOS women typically display elevated gonadotrophin ratios, lower insulin resistance, higher androgen levels, including adrenal androgens, and more favourable lipid profiles. Overall, these findings add to the growing body of evidence supporting a genetic basis for PCOS as well as differences in genetic patterns relevant to PCOS BMI-subtype.

Heterogeneous effects on type 2 diabetes and cardiovascular outcomes of genetic variants and traits associated with fasting insulin.

Hyperinsulinemia is a complex and heterogeneous phenotype that characterizes molecular alterations that precede the development of type 2 diabetes (T2D). It results from a complex combination of molecular processes, including insulin secretion and insulin sensitivity, that differ between individuals. To better understand the physiology of hyperinsulinemia and ultimately T2D, we implemented a genetic approach grouping fasting insulin (FI)-associated genetic variants based on their molecular and phenotypic similarities. We identified seven distinctive genetic clusters representing different physiologic mechanisms leading to rising FI levels, ranging from clusters of variants with effects on increased FI, but without increased risk of T2D (non-diabetogenic hyperinsulinemia), to clusters of variants that increase FI and T2D risk with demonstrated strong effects on body fat distribution, liver, lipid, and inflammatory processes (diabetogenic hyperinsulinemia). We generated cluster-specific polygenic scores in 1,104,258 individuals from five multi-ancestry cohorts to show that the clusters differed in associations with cardiometabolic traits. Among clusters characterized by non-diabetogenic hyperinsulinemia, there was both increased and decreased risk of coronary artery disease despite the non-increased risk of T2D. Similarly, the clusters characterized by diabetogenic hyperinsulinemia were associated with an increased risk of T2D, yet had differing risks of cardiovascular conditions, including coronary artery disease, myocardial infarction, and stroke. The strongest cluster-T2D associations were observed with the same direction of effect in non-Hispanic Black, Hispanic, non-Hispanic White, and non-Hispanic East Asian populations. These genetic clusters provide important insights into granular metabolic processes underlying the physiology of hyperinsulinemia, notably highlighting specific processes that decouple increasing FI levels from T2D and cardiovascular risk. Our findings suggest that increasing FI levels are not invariably associated with adverse cardiometabolic outcomes.

Infertility and treatments used have minimal effects on first-trimester placental DNA methylation and gene expression.

OBJECTIVE: To determine whether deoxyribonucleic acid (DNA) methylation alterations exist in the first-trimester human placenta between conceptions using fertility treatments and those that do not and, if so, whether they are the result of underlying infertility or fertility treatments. We also assessed whether significant alterations led to changes in gene expression. DESIGN: We compared DNA methylation of the first-trimester placenta from singleton pregnancies that resulted in live births from unassisted, in vitro fertilization (IVF), and non-IVF fertility treatment (NIFT) conceptions using the Infinium MethylationEPIC BeadChip array. Significant CpG sites were compared with corresponding ribonucleic acid sequencing analysis in similar cohorts to determine whether methylation alterations lead to differences in gene expression. SETTING: Academic medical center. PATIENT(S): A total of 138 singleton pregnancies undergoing chorionic villus sampling resulting in a live birth were recruited for methylation analysis (56 unassisted, 38 NIFT, and 44 IVF conceptions). Ribonucleic acid-sequencing data consisted of 141 subjects (74 unassisted, 33 NIFT, and 34 IVF conceptions) of which 116 overlapped with the methylation cohort. INTERVENTION(S): In vitro fertilization-conceived pregnancy or pregnancy conceived via NIFT, such as ovulation induction and intrauterine insemination. MAIN OUTCOME MEASURE(S): Significant methylation changes at CpG sites after adjustment for multiple comparisons. The secondary outcome was gene expression changes of significant CpG sites. RESULT(S): Of the 741,145 probes analyzed in the placenta, few were significant at Bonferroni <0.05: 185 CpG sites (0.025%) significant in pregnancies conceived with the fertility treatments (NIFT + IVF) vs. unassisted conceptions; 28 in NIFT vs. unassisted; 195 in IVF vs. unassisted; and only 13 (0.0018%) in IVF vs. NIFT conceptions. Of all significant CpG sites combined, 10% (35) were located in genes with suggestive gene expression changes, but none were significant after adjustment for multiple comparisons (ribonucleic acid sequencing false discovery rate <0.05). None of the 13 differentially methylated probes in the IVF vs. NIFT placenta were located in genes with suggestive IVF vs. NIFT gene expression differences. CONCLUSION(S): Underlying infertility is the most significant contributor to the minimal differences in first-trimester placental methylation, and not the specific fertility treatment used, such as IVF.

Butyrate-Producing Bacteria and Insulin Homeostasis: The Microbiome and Insulin Longitudinal Evaluation Study (MILES).

Gut microbiome studies have documented depletion of butyrate-producing taxa in type 2 diabetes. We analyzed associations between butyrate-producing taxa and detailed measures of insulin homeostasis, whose dysfunction underlies diabetes in 224 non-Hispanic Whites and 129 African Americans, all of whom completed an oral glucose tolerance test. Stool microbiome was assessed by whole-metagenome shotgun sequencing with taxonomic profiling. We examined associations among 36 butyrate-producing taxa (n = 7 genera and 29 species) and insulin sensitivity, insulin secretion, disposition index, insulin clearance, and prevalence of dysglycemia (prediabetes plus diabetes, 46% of cohort), adjusting for age, sex, BMI, and race. The genus Coprococcus was associated with higher insulin sensitivity (ß = 0.14; P = 0.002) and disposition index (ß = 0.12; P = 0.012) and a lower rate of dysglycemia (odds ratio [OR] 0.91; 95% CI 0.85-0.97; P = 0.0025). In contrast, Flavonifractor was associated with lower insulin sensitivity (ß = -0.13; P = 0.004) and disposition index (ß = -0.11; P = 0.04) and higher prevalence of dysglycemia (OR 1.22; 95% CI 1.08-1.38; P = 0.0013). Species-level analyses found 10 bacteria associated with beneficial directions of effects and two bacteria with adverse associations on insulin homeostasis and dysglycemia. Although most butyrate producers analyzed appear to be metabolically beneficial, this is not the case for all such bacteria, suggesting that microbiome-directed therapeutic measures to prevent or treat diabetes should be targeted to specific butyrate-producing taxa rather than all butyrate producers.

Polycystic Ovary Syndrome and Risk of Type 2 Diabetes, Coronary Heart Disease, and Stroke.

Polycystic ovary syndrome (PCOS) has been associated with diabetes and cardiovascular disease; however, whether the relationship is causal is uncertain. We conducted a two-sample Mendelian randomization study to investigate the associations of PCOS with type 2 diabetes, coronary heart disease (CHD), and stroke. Association between PCOS and diabetes risk was examined in European and Asian cohorts, both sex specific and sex combined. Causal effects of PCOS on risks of CHD and stroke were evaluated in European cohorts. Stroke was analyzed as any stroke as well as four subtypes of stroke (ischemic, large artery, cardioembolic, small vessel). We found no association of genetically predicted PCOS with risk of diabetes, CHD, or stroke. This suggests that PCOS in and of itself does not increase the risk of these outcomes. Other features of PCOS (obesity, elevated testosterone, low sex hormone binding globulin) may explain the association between PCOS and cardiometabolic diseases. In light of these results, efforts to prevent cardiometabolic complications in PCOS should focus on women with high-risk features rather than all women with PCOS.

Physical Activity Associations with Bone Mineral Density and Modification by Metabolic Traits.

OBJECTIVE: To assess the relationship of physical activity with bone mineral density (BMD) at various sites and examine potential modifying metabolic factors. METHODS: Responses from physical activity questionnaires were used to determine total physical activity (PA), moderate physical activity (mod-PA), and sedentary time. Regression analyses were performed to evaluate association of activity traits with insulin sensitivity by euglycemic clamp, adiponectin, C-reactive protein (CRP), and plasminogen activator inhibitor-1 (PAI-1) in 741 healthy subjects. RESULTS: The cohort was relatively sedentary. Activity level was associated with arm, pelvis, and leg BMD in univariate analyses. In multivariate association analyses of arm BMD, only female sex (ß = -0.73, P < 0.0001) and adiponectin (ß = -0.076, P = 0.0091) were significant. Multivariate analyses of pelvis BMD found independent associations with body mass index (BMI) (ß = 0.33, P < 0.0001), adiponectin (ß = -0.10, P = 0.013), female sex (ß = -0.18, P < 0.0001), sedentary time (ß = -0.088, P = 0.034), PA (ß = 0.11, P = 0.01), and mod-PA (ß = 0.11, P = 0.014). Age (ß = -0.10, P = 0.0087), female sex (ß = -0.63, P < 0.0001), BMI (ß = 0.24, P < 0.0001), and mod-PA (ß = 0.10, P = 0.0024) were independently associated with leg BMD. CONCLUSIONS: These results suggest that BMD increases with physical activity in the arms, legs, and pelvis and is inversely related to sedentary time in the pelvis and legs; these associations may be modified by age, sex, BMI, and adiponectin, depending on the site, with physical activity being more important to pelvis and leg BMD than arm BMD and sedentary time being important for pelvis BMD. Moreover, we demonstrated that CRP, PAI-1, and insulin sensitivity play a minor role in BMD.

Plasma 25-hydroxyvitamin D level and the risk of frailty among Chinese community-based oldest-old: evidence from the CLHLS study.

BACKGROUND: Vitamin D deficiency has been linked to the risk of frailty. However, there are limited methods for evaluations of the potential association of vitamin D with frailty in a longevous (80+) population. The aim of this study was to examine the association between plasma 25-hydroxyvitamin D [25(OH)D] levels and the risk of frailty among the Chinese community based oldest-old. METHODS: Secondary analysis of data compiled in the 2011 wave of the Chinese Longitudinal Healthy Longevity Survey (n = 1324) was performed. Frailty was assessed by the Study of Osteoporotic Fractures (SOF) index. Multivariate logistic regression and spline smoothing with threshold effect analysis were performed to investigate the association between 25(OH) D level and the risk of frailty after adjusting for socio-demographic variables, health characteristics and confounding biomarkers. RESULTS: The mean age was 92.89 ± 7.92 years, and 844 (63.7%) participants were women. In all, data from 426 (33.2, 95% confidence interval, CI: 29.66-34.69) frail participants were recorded. After adjustment for confounding covariates, the level of 25(OH) D was significantly related to frailty. By spline smoothing with threshold effect analysis, a monotonically negative association between 25(OH) D and frailty was identified. Subgroup analyses revealed that the association did not differ by sex or age. CONCLUSIONS: The 25(OH) D level was inversely associated with the risk of frailty among the Chinese community-based oldest-old.

Classification of Type 2 Diabetes Genetic Variants and a Novel Genetic Risk Score Association With Insulin Clearance.

CONTEXT: Genome-wide association studies have identified more than 450 single nucleotide polymorphisms (SNPs) for type 2 diabetes (T2D). OBJECTIVE: To facilitate use of these SNPs in future genetic risk score (GRS)-based analyses, we aimed to classify the SNPs based on physiology. We also sought to validate GRS associations with insulin-related traits in deeply phenotyped Mexican Americans. DESIGN, SETTING, AND PARTICIPANTS: A total of 457 T2D SNPs from the literature were assigned physiologic function based on association studies and cluster analyses. All SNPs (All-GRS), beta-cell (BC-GRS), insulin resistance (IR-GRS), lipodystrophy (Lipo-GRS), and body mass index plus lipids (B + L-GRS) were evaluated for association with diabetes and indices of insulin secretion (from oral glucose tolerance test), insulin sensitivity and insulin clearance (from euglycemic clamp), and adiposity and lipid markers in 1587 Mexican Americans. RESULTS: Of the 457 SNPs, 52 were classified as BC, 30 as IR, 12 as Lipo, 12 as B + L, whereas physiologic function of 351 was undefined. All-GRS was strongly associated with T2D. Among nondiabetic Mexican Americans, BC-GRS was associated with reduced insulinogenic index, IR-GRS was associated with reduced insulin sensitivity, and Lipo-GRS was associated with reduced adiposity. B + L-GRS was associated with increased insulin clearance. The latter did not replicate in an independent cohort wherein insulin clearance was assessed by a different method. CONCLUSIONS: Supporting their utility, BC-GRS, IR-GRS, and Lipo-GRS, based on SNPs discovered largely in Europeans, exhibited expected associations in Mexican Americans. The novel association of B + L-GRS with insulin clearance suggests that impaired ability to reduce insulin clearance in compensation for IR may play a role in the pathogenesis of T2D. Whether this applies to other ethnic groups remains to be determined.

Genetic Risk Score in Diabetes Associated With Chronic Pancreatitis Versus Type 2 Diabetes Mellitus.

INTRODUCTION: Diabetes mellitus (DM) is a complication of chronic pancreatitis (CP). Whether pancreatogenic diabetes associated with CP-DM represents a discrete pathophysiologic entity from type 2 DM (T2DM) remains uncertain. Addressing this question is needed for development of specific measures to manage CP-DM. We approached this question from a unique standpoint, hypothesizing that if CP-DM and T2DM are separate disorders, they should be genetically distinct. To test this hypothesis, we sought to determine whether a genetic risk score (GRS) based on validated single nucleotide polymorphisms for T2DM could distinguish between groups with CP-DM and T2DM. METHODS: We used 60 T2DM single nucleotide polymorphisms to construct a weighted GRS in 1,613 subjects from the North American Pancreatitis Study 2 and 2,685 subjects from the Multi-Ethnic Study of Atherosclerosis, all of European origin. RESULTS: The mean GRS was identical between 321 subjects with CP-DM and 423 subjects with T2DM (66.53 vs 66.42, P = 0.95), and the GRS of both diabetic groups was significantly higher than that of nondiabetic controls (n = 3,554, P < 0.0001). Exploratory analyses attempting to enrich the CP-DM group for pancreatogenic diabetes, such as eliminating diabetes diagnosed before CP, requiring pancreas-specific comorbidities, or removing those with a family history of diabetes, did not improve the ability of the GRS to distinguish between CP-DM and T2DM. DISCUSSION: Recognizing that we lacked a gold standard to define CP-DM, our study suggests that CP-DM may be a subtype of T2DM, a notion that should be tested in future, large prospective studies.

Adiposity-Independent Effects of Aging on Insulin Sensitivity and Clearance in Mice and Humans.

OBJECTIVE: Aging is associated with impaired insulin sensitivity and increased prevalence of type 2 diabetes. However, it remains unclear whether aging-associated insulin resistance is due to increased adiposity or other age-related factors. To address this question, the impact of aging on insulin sensitivity was investigated independently of changes in body composition. METHODS: Cohorts of mice aged 4 to 8 months ("young") and 18 to 27 months ("aged") exhibiting similar body composition were characterized for glucose metabolism on chow and high-fat diets. Insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamp analyses. The relationship between aging and insulin resistance in humans was investigated in 1,250 nondiabetic Mexican Americans who underwent hyperinsulinemic-euglycemic clamps. RESULTS: In mice with similar body composition, age had no detrimental effect on plasma glucose and insulin levels. While aging did not diminish glucose tolerance, hyperinsulinemic-euglycemic clamps demonstrated impaired insulin sensitivity and reduced insulin clearance in aged mice on chow and high-fat diets. Consistent with results in the mouse, age remained an independent determinant of insulin resistance after adjustment for body composition in Mexican American males. CONCLUSIONS: This study demonstrates that in addition to altered body composition, adiposity-independent mechanisms also contribute to aging-associated insulin resistance in mice and humans.

Association between site-specific bone mineral density and glucose homeostasis and anthropometric traits in healthy men and women.

OBJECTIVE: Patients with type 2 diabetes mellitus have an increased risk of fracture despite normal or increased bone mineral density (BMD). Studies on the relationship of glucose homeostasis with BMD phenotypes have been inconclusive because distinguishing the roles of insulin resistance and hyperglycaemia in bone remodelling is challenging. In this study, we sought to define the relationship of site-specific BMD with glucose homeostasis traits and anthropometric traits. DESIGN/PATIENTS/MEASUREMENTS: In a cross-sectional study, we examined 787 subjects from the Mexican-American Coronary Artery Disease (MACAD) cohort who had undergone euglycaemic-hyperinsulinaemic clamps, oral glucose tolerance testing and dual X-ray absorptiometry. Glucose homeostasis traits included insulinogenic index (IGI30), insulin sensitivity (M value), insulin clearance (MCRI), fasting insulin, fasting glucose and 2-hour glucose. Univariate and multivariate analyses were performed to assess the association of glucose homeostasis and anthropometric traits with site-specific BMD. RESULTS: Two-hour glucose was negatively associated with arm BMD in women, which remained significant in multivariate analysis (ß = -.15, P = .0015). Positive correlations between fasting insulin and BMD at weight-bearing sites, including pelvis (ß = .22, P < .0001) and legs (ß = .17, P = .001) in women and pelvis (ß = .33, P < .0001) in men, lost significance after multivariate adjustment. Lean mass exhibited strong independent positive associations with BMD at multiple sites in both sexes. CONCLUSION: Our findings suggest that (i) anabolic effects of insulin might work via mechanical loading from lean mass; (ii) a direct negative effect of increasing glucose might be more prominent at cortical-bone-rich sites in women; and (iii) lean mass is a strong positive predictor of bone mass.

Up-regulation of microRNA-202-3p in first trimester placenta of pregnancies destined to develop severe preeclampsia, a pilot study.

MicroRNA (miRNA) expression has not been studied during placentation in pregnancies that develop preeclampsia, when it likely manifests. In this pilot study, miRNA expression in late first trimester placenta from four pregnancies that developed severe preeclampsia matched to controls using the Affymetrix GeneChip® miRNA 3.0 Array identified 9 miRNAs differentially expressed, with miR-202-3p the most significantly overexpressed in severe preeclampsia. Real-time reverse transcription polymerase chain reaction (qRT-PCR) confirmed overexpression of miR-202-3p in a validation cohort, with a 7-fold increase in pregnancies that developed severe preeclampsia (p≤0.05). Differential miRNA expression, specifically miR-202-3p, is seen in first trimester placenta in severe preeclampsia.

The Association of Estrogen Receptor-ß Gene Variation With Salt-Sensitive Blood Pressure.

Context: Hypertension in young women is uncommon compared with young men and older women. Estrogen appears to protect most women against hypertension, with incidence increasing after menopause. Because some premenopausal women develop hypertension, estrogen may play a different role in these women. Genetic variations in the estrogen receptor (ER) are associated with cardiovascular disease. ER-ß, encoded by ESR2, is the ER predominantly expressed in vascular smooth muscle. Objective: To determine an association of single nucleotide polymorphisms in ESR2 with salt sensitivity of blood pressure (SSBP) and estrogen status in women. Methods: Candidate gene association study with ESR2 and SSBP conducted in normotensive and hypertensive women and men in two cohorts: International Hypertensive Pathotype (HyperPATH) (n = 584) (discovery) and Mexican American Hypertension-Insulin Resistance Study (n = 662) (validation). Single nucleotide polymorphisms in ESR1 (ER-α) were also analyzed. Analysis conducted in younger (<51 years, premenopausal, "estrogen-replete") and older women (≥51 years, postmenopausal, "estrogen-deplete"). Men were analyzed to control for aging. Results: Multivariate analyses of HyperPATH data between variants of ESR2 and SSBP documented that ESR2 rs10144225 minor (risk) allele carriers had a significantly positive association with SSBP driven by estrogen-replete women (ß = +4.4 mm Hg per risk allele, P = 0.004). Findings were confirmed in Hypertension Insulin-Resistance Study premenopausal women. HyperPATH cohort analyses revealed risk allele carriers vs noncarriers had increased aldosterone/renin ratios. No associations were detected with ESR1. Conclusions: The variation at rs10144225 in ESR2 was associated with SSBP in premenopausal women (estrogen-replete) and not in men or postmenopausal women (estrogen-deplete). Inappropriate aldosterone levels on a liberal salt diet may mediate the SSBP.

Comparison of Genome-Wide and Gene-Specific DNA Methylation Profiling in First-Trimester Chorionic Villi From Pregnancies Conceived With Infertility Treatments.

BACKGROUND: Assisted reproductive technologies are associated with altered methylation in term placenta. However, it is unclear whether methylation patterns are the result of fertility treatments or intrauterine environment. Thus, we set out to determine whether there are differences in the first-trimester placenta that may be altered by the underlying fertility treatments. Genome-wide DNA methylation analyses from chorionic villus sampling (CVS) from matched singleton pregnancies conceived using in vitro fertilization (IVF), non-IVF fertility treatment (NIFT), or those conceived spontaneously were performed using Illumina Infinium HumanMethylation450 BeadChip from 15 matched CVS samples. Nanofluidic quantitative polymerase chain reaction (qPCR) of differently methylated genes was performed in a confirmatory cohort of 23 IVF conceptions and 24 NIFT conceptions. RESULTS: Global methylation was similar among the IVF, NIFT, and spontaneous conceptions. However, differential methylation from IVF and NIFT pregnancies was present at 34 CpG sites, which was significantly different. Of those, 14 corresponded to known genes, with methylation changes detected at multiple loci in 3 genes, anaphase-promoting complex subunit 2 ( ANAPC2), C-X-C motif chemokine ligand 14 ( CXCL14), and regulating synaptic membrane exocytosis 1 ( RIMS1). Nanofluidic qPCR of differentially methylated genes identified pre T-cell antigen receptor alpha ( PTCRA) to be significantly downregulated in IVF versus NIFT conceptions. CONCLUSION: Although global methylation patterns are similar, there are differences in methylation of specific genes in IVF compared to NIFT conceptions, leading to altered gene expression. PTCRA was differentially methylated and downregulated in IVF conceptions, warranting further investigation. It remains to be determined whether these changes affect placentation and whether it is due to the more profound underlying infertility requiring IVF, yet these data provide unique insight into the first-trimester placental epigenome.

Insulin Clearance Is Associated with Hepatic Lipase Activity and Lipid and Adiposity Traits in Mexican Americans.

Reduction in insulin clearance plays an important role in the compensatory response to insulin resistance. Given the importance of this trait to the pathogenesis of diabetes, a deeper understanding of its regulation is warranted. Our goal was to identify metabolic and cardiovascular traits that are independently associated with metabolic clearance rate of insulin (MCRI). We conducted a cross-sectional analysis of metabolic and cardiovascular traits in 765 participants from the Mexican-American Coronary Artery Disease (MACAD) project who had undergone blood sampling, oral glucose tolerance test, euglycemic-hyperinsulinemic clamp, dual-energy X-ray absorptiometry, and carotid ultrasound. We assessed correlations of MCRI with traits from seven domains, including anthropometry, biomarkers, cardiovascular, glucose homeostasis, lipase activity, lipid profile, and liver function tests. We found inverse independent correlations between MCRI and hepatic lipase (P = 0.0004), insulin secretion (P = 0.0002), alanine aminotransferase (P = 0.0045), total fat mass (P = 0.014), and diabetes (P = 0.03). MCRI and apolipoprotein A-I exhibited a positive independent correlation (P = 0.035). These results generate a hypothesis that lipid and adiposity associated traits related to liver function may play a role in insulin clearance.

Association of polymorphisms of rs179247 and rs12101255 in thyroid stimulating hormone receptor intron 1 with an increased risk of Graves' disease: A meta-analysis.

The polymorphisms of thyroid stimulating hormone receptor (TSHR) intron 1 rs179247 and rs12101255 have been found to be associated with Graves' disease (GD) in genetic studies. In the present study, we conducted a meta-analysis to examine this association. Two reviewers systematically searched eligible studies in PubMed, Web of Science, Embase and China Biomedical Literature Database (CBM). A meta-analysis on the association between GD and TSHR intron 1 rs179247 or rs12101255 was performed. The odd ratios (OR) were estimated with 95% confidence interval (CI). Meta package in R was used for the analyses. Seven articles (13 studies) published between 2009 and 2014, involving 5754 GD patients and 5768 controls, were analyzed. The polymorphism of rs179247 was found to be associated with an increased GD risk in the allele analysis (A vs. G: OR=1.40, 95% CI=1.33-1.48) and all genetic models (AA vs. GG: OR=1.94, 95% CI=1.73-2.19; AA+AG vs. GG: OR=1.57, 95% CI=1.41-1.74; AA vs. AG+GG: OR=1.54, 95% CI=1.43-1.66). The site rs12101255 also conferred a risk of GD in the allele analysis (T vs. C: OR=1.50, 95% CI=1.40-1.60) and all genetic models (TT vs. CC: OR=2.22, 95% CI=1.92-2.57; TT+TC vs. CC: OR=1.66, 95% CI=1.50-1.83; TT vs. TC+CC: OR=1.74, 95% CI=1.53-1.98). Analysis of the relationship between rs179247 and Graves' ophthalmopathy (GO) showed no statistically significant correlation (A vs. G: OR=1.02, 95% CI=0.97-1.07). Publication bias was not significant. In conclusion, GD is associated with polymorphisms of TSHR intron 1 rs179247 and rs12101255. There is no association between rs179247 SNPs and GO.

A prevalent caveolin-1 gene variant is associated with the metabolic syndrome in Caucasians and Hispanics.

CONTEXT AND OBJECTIVE: We examined whether a prevalent caveolin-1 gene (CAV1) variant, previously related to insulin resistance, is associated with metabolic syndrome (MetS). PATIENTS AND METHODS: We included subjects genotyped for the CAV1 variant rs926198 from two cohorts: 735 Caucasians from the HyperPATH multicenter study, and 810 Hispanic participants from the HTN-IR cohort. RESULTS: Minor allele carriers from HyperPATH cohort (57% of subjects) had higher Framingham risk scores, higher odds of diabetes (10.7% vs 5.7%, p=0.016), insulin resistance (44.3% vs 35.1%, p=0.022), low HDL (49.3% vs 39.6%, p=0.018) and MetS (33% vs 20.5%, p<0.001) but similar BMI. Consistently, minor allele carriers exhibited higher odds of MetS, even when adjusted for confounders and relatedness (OR 2.83 (1.73-4.63), p<0.001). The association with MetS was replicated in the Hispanic cohort HTN-IR (OR 1.61, [1.06-2.44], p=0.025). Exploratory analyses suggest that MetS risk is modified by a CAV1 variant-BMI status interaction, whereby the minor allele carrier status strongly predicted MetS (OR 3.86 [2.05-7.27], p<0.001) and diabetes (OR 2.27 [1.07-4.78], p=0.03) in non-obese, but not in obese subjects. In addition, we observed a familial aggregation for MetS diagnosis in minor allele carriers. CONCLUSION: The prevalent CAV1 gene variant rs926198 is associated with MetS in separate Caucasian and Hispanic cohorts. These findings appear to be driven by an interaction between the genetic marker and obesity status, suggesting that the CAV1 variant may improve risk profiling in non-obese subjects. Additional studies are needed to confirm the clinical implications of our results.

Systems Genetics Reveals the Functional Context of PCOS Loci and Identifies Genetic and Molecular Mechanisms of Disease Heterogeneity.

Genome wide association studies (GWAS) have revealed 11 independent risk loci for polycystic ovary syndrome (PCOS), a common disorder in young women characterized by androgen excess and oligomenorrhea. To put these risk loci and the single nucleotide polymorphisms (SNPs) therein into functional context, we measured DNA methylation and gene expression in subcutaneous adipose tissue biopsies to identify PCOS-specific alterations. Two genes from the LHCGR region, STON1-GTF2A1L and LHCGR, were overexpressed in PCOS. In analysis stratified by obesity, LHCGR was overexpressed only in non-obese PCOS women. Although not differentially expressed in the entire PCOS group, INSR was underexpressed in obese PCOS subjects only. Alterations in gene expression in the LHCGR, RAB5B and INSR regions suggest that SNPs in these loci may be functional and could affect gene expression directly or indirectly via epigenetic alterations. We identified reduced methylation in the LHCGR locus and increased methylation in the INSR locus, changes that are concordant with the altered gene expression profiles. Complex patterns of meQTL and eQTL were identified in these loci, suggesting that local genetic variation plays an important role in gene regulation. We propose that non-obese PCOS women possess significant alterations in LH receptor expression, which drives excess androgen secretion from the ovary. Alternatively, obese women with PCOS possess alterations in insulin receptor expression, with underexpression in metabolic tissues and overexpression in the ovary, resulting in peripheral insulin resistance and excess ovarian androgen production. These studies provide a genetic and molecular basis for the reported clinical heterogeneity of PCOS.

Genetic Variants Associated With Quantitative Glucose Homeostasis Traits Translate to Type 2 Diabetes in Mexican Americans: The GUARDIAN (Genetics Underlying Diabetes in Hispanics) Consortium.

Insulin sensitivity, insulin secretion, insulin clearance, and glucose effectiveness exhibit strong genetic components, although few studies have examined their genetic architecture or influence on type 2 diabetes (T2D) risk. We hypothesized that loci affecting variation in these quantitative traits influence T2D. We completed a multicohort genome-wide association study to search for loci influencing T2D-related quantitative traits in 4,176 Mexican Americans. Quantitative traits were measured by the frequently sampled intravenous glucose tolerance test (four cohorts) or euglycemic clamp (three cohorts), and random-effects models were used to test the association between loci and quantitative traits, adjusting for age, sex, and admixture proportions (Discovery). Analysis revealed a significant (P < 5.00 × 10(-8)) association at 11q14.3 (MTNR1B) with acute insulin response. Loci with P < 0.0001 among the quantitative traits were examined for translation to T2D risk in 6,463 T2D case and 9,232 control subjects of Mexican ancestry (Translation). Nonparametric meta-analysis of the Discovery and Translation cohorts identified significant associations at 6p24 (SLC35B3/TFAP2A) with glucose effectiveness/T2D, 11p15 (KCNQ1) with disposition index/T2D, and 6p22 (CDKAL1) and 11q14 (MTNR1B) with acute insulin response/T2D. These results suggest that T2D and insulin secretion and sensitivity have both shared and distinct genetic factors, potentially delineating genomic components of these quantitative traits that drive the risk for T2D.