A genome-wide association meta-analysis of circulating sex hormone-binding globulin reveals multiple Loci implicated in sex steroid hormone regulation

Association Between Low Sex Hormone-Binding Globulin and Increased Risk of Type 2 Diabetes Is Mediated by Increased Visceral and Liver Fat: Results From Observational and Mendelian Randomization Analyses

The aim of this study was to investigate the associations among sex hormone-binding globulin (SHBG), visceral adipose tissue (VAT), liver fat content, and risk of type 2 diabetes (T2D). In the Netherlands Epidemiology of Obesity study, 5,690 women (53%) and men (47%) without preexisting diabetes were included and followed for incident T2D. SHBG concentrations were measured in all participants, VAT was measured using MRI, and liver fat content was measured using proton magnetic resonance spectroscopy in a random subset of 1,822 participants. We examined associations between SHBG and liver fat using linear regression and bidirectional Mendelian randomization analyses and between SHBG and T2D using Cox regression adjusted for confounding and additionally for VAT and liver fat to examine mediation. Mean age was 56 (SD 6) years, mean BMI was 30 (SD 4) kg/m2, median SHBG was 47 (interquartile range [IQR] 34-65) nmol/L in women and 34 (26-43) nmol/L in men, and median liver fat was 3.4% (IQR 1.6-8.2%) in women and 6.0% (2.9-13.5%) in men. Compared with the highest SHBG quartile, liver fat was 2.9-fold (95% CI 2.4, 3.4) increased in women and 1.6-fold (95% CI 1.3, 1.8) increased in men, and the hazard ratio of T2D was 4.9 (95% CI 2.4, 9.9) in women and 1.8 (1.1, 2.9) in men. Genetically predicted SHBG was associated with liver fat content (women: SD -0.45 [95% CI -0.55, -0.35]; men: natural logarithm, -0.25 [95% CI -0.34, -0.16]). VAT and liver fat together mediated 43% (women) and 60% (men) of the SHBG-T2D association. To conclude, in a middle-aged population with overweight, the association between low SHBG and increased risk of T2D was, for a large part, mediated by increased VAT and liver fat.

ARTICLE HIGHLIGHTS

Sex hormones and risk of lung and colorectal cancers in women: a Mendelian randomization study

The roles of sex hormones such as estradiol, testosterone, and sex hormone-binding globulin (SHBG) in the etiology of lung and colorectal cancers in women, among the most common cancers after breast cancer, are unclear. This Mendelian randomization (MR) study evaluated such potential causal associations in women of European ancestry. We used summary statistics data from genome-wide association studies on sex hormones and from the Trøndelag Health Study (HUNT) and large consortia on cancers. There was suggestive evidence of 1-standard deviation increase in total testosterone levels being associated with a lower risk of lung non-adenocarcinoma (hazard ratio 0.60, 95% confidence interval 0.37-0.98) in the HUNT Study. However, this was not confirmed by using data from a larger consortium. In general, we did not find convincing evidence to support a causal role of sex hormones on risk of lung and colorectal cancers in women of European ancestry.

Innovative strategies in genitourinary cancer: the role of oncolytic viruses

Urinary tumors pose a significant health threat because of their high prevalence and recurrence rates. Despite the availability of various treatment options, many patients poorly respond to traditional therapies, highlighting the urgent need for alternative approaches. Oncolytic viruses are promising therapeutic agents. These viruses exploit the unique characteristics of cancer cells to specifically target and destroy them, thereby triggering potent antitumor immune responses. This review delves into recent advancements and future prospects of oncolytic viruses, focusing on their application in renal, bladder, and prostate cancers. By discussing practical implications and the potential of different viruses, including the cowpox virus, adenovirus, measles virus, coxsackievirus, and reovirus, we pave the way for further exploration and refinement of this exciting field.

Sex hormone-binding globulin and its critical role in prostate cancer: A comprehensive review

Prostate cancer (PC) is a common and widespread cancer that affects men globally. A complicated interaction of hormonal variables influences its development. Sex hormone-binding globulin (SHBG) is a crucial element in controlling the availability of sex hormones, especially androgens, which have a notable impact on the development and progression of PC. SHBG controls the levels of free, active androgens in the body, which helps regulate androgen-dependent processes associated with PC. The equilibrium between SHBG and androgens plays a critical role in maintaining the stability of the prostate. When this balance is disrupted, it is associated with the development and advancement of PC. The processes responsible for SHBG's role in PC are complex and have multiple aspects. SHBG primarily binds to androgens, preventing them from interacting with androgen receptors (ARs) in prostate cells. It reduces the activation of androgen signaling pathways essential for tumor development and survival. In addition, SHBG can directly affect prostate cells by interacting with specific receptors on the cell surface. This review thoroughly examines the role of SHBG in PC, including its physiological activities, methods of action, and clinical consequences.

Sex hormones and risk of lung and colorectal cancers in women: a Mendelian randomization study

The roles of sex hormones such as estradiol, testosterone, and sex hormone-binding globulin (SHBG) in the etiology of lung and colorectal cancers in women, among the most common cancers after breast cancer, are unclear. This Mendelian randomization (MR) study evaluated such potential causal associations in women of European ancestry. We used summary statistics data from genome-wide association studies (GWASs) on sex hormones and from the Trøndelag Health (HUNT) Study and large consortia on cancers. There was suggestive evidence of genetically predicted 1-standard deviation increase in total testosterone levels being associated with a lower risk of lung non-adenocarcinoma (hazard ratio (HR) 0.60, 95% CI 0.37-0.98) in the HUNT Study. However, this was not confirmed by using data from a larger consortium. In general, we did not find convincing evidence to support a causal role of sex hormones on risk of lung and colorectal cancers in women of European ancestry.

Obesity-Dependent Association of the rs10454142 PPP1R21 with Breast Cancer

The purpose of this work was to find a link between the breast cancer (BC)-risk effects of sex hormone-binding globulin (SHBG)-associated polymorphisms and obesity. The study was conducted on a sample of 1498 women (358 BC; 1140 controls) who, depending on the presence/absence of obesity, were divided into two groups: obese (119 BC; 253 controls) and non-obese (239 BC; 887 controls). Genotyping of nine SHBG-associated single nucleotide polymorphisms (SNP)-rs17496332 PRMT6, rs780093 GCKR, rs10454142 PPP1R21, rs3779195 BAIAP2L1, rs440837 ZBTB10, rs7910927 JMJD1C, rs4149056 SLCO1B1, rs8023580 NR2F2, and rs12150660 SHBG-was executed, and the BC-risk impact of these loci was analyzed by logistic regression separately in each group of obese/non-obese women. We found that the BC-risk effect correlated by GWAS with the SHBG-level polymorphism rs10454142 PPP1R21 depends on the presence/absence of obesity. The SHBG-lowering allele C rs10454142 PPP1R21 has a risk value for BC in obese women (allelic model: CvsT, OR = 1.52, 95%CI = 1.10-2.11, and pperm = 0.013; additive model: CCvsTCvsTT, OR = 1.71, 95%CI = 1.15-2.62, and pperm = 0.011; dominant model: CC + TCvsTT, OR = 1.95, 95%CI = 1.13-3.37, and pperm = 0.017) and is not associated with the disease in women without obesity. SNP rs10454142 PPP1R21 and 10 proxy SNPs have adipose-specific regulatory effects (epigenetic modifications of promoters/enhancers, DNA interaction with 51 transcription factors, eQTL/sQTL effects on five genes (PPP1R21, RP11-460M2.1, GTF2A1L, STON1-GTF2A1L, and STON1), etc.), can be "likely cancer driver" SNPs, and are involved in cancer-significant pathways. In conclusion, our study detected an obesity-dependent association of the rs10454142 PPP1R21 with BC in women.

Genetic contribution of reproductive traits to risk of uterine leiomyomata: a large-scale, genome-wide, cross-trait analysis

BACKGROUND

Although phenotypic associations between female reproductive characteristics and uterine leiomyomata have long been observed in epidemiologic investigations, the shared genetic architecture underlying these complex phenotypes remains unclear.

OBJECTIVE

We aimed to investigate the shared genetic basis, pleiotropic effects, and potential causal relationships underlying reproductive traits (age at menarche, age at natural menopause, and age at first birth) and uterine leiomyomata.

STUDY DESIGN

With the use of large-scale, genome-wide association studies conducted among women of European ancestry for age at menarche (n=329,345), age at natural menopause (n=201,323), age at first birth (n=418,758), and uterine leiomyomata (ncases/ncontrols=35,474/267,505), we performed a comprehensive, genome-wide, cross-trait analysis to examine systematically the common genetic influences between reproductive traits and uterine leiomyomata.

RESULTS

Significant global genetic correlations were identified between uterine leiomyomata and age at menarche (rg, -0.17; P=3.65×10-10), age at natural menopause (rg, 0.23; P=3.26×10-07), and age at first birth (rg, -0.16; P=1.96×10-06). Thirteen genomic regions were further revealed as contributing significant local correlations (P<.05/2353) to age at natural menopause and uterine leiomyomata. A cross-trait meta-analysis identified 23 shared loci, 3 of which were novel. A transcriptome-wide association study found 15 shared genes that target tissues of the digestive, exo- or endocrine, nervous, and cardiovascular systems. Mendelian randomization suggested causal relationships between a genetically predicted older age at menarche (odds ratio, 0.88; 95% confidence interval, 0.85-0.92; P=1.50×10-10) or older age at first birth (odds ratio, 0.95; 95% confidence interval, 0.90-0.99; P=.02) and a reduced risk for uterine leiomyomata and between a genetically predicted older age at natural menopause and an increased risk for uterine leiomyomata (odds ratio, 1.08; 95% confidence interval, 1.06-1.09; P=2.30×10-27). No causal association in the reverse direction was found.

CONCLUSION

Our work highlights that there are substantial shared genetic influences and putative causal links that underlie reproductive traits and uterine leiomyomata. The findings suggest that early identification of female reproductive risk factors may facilitate the initiation of strategies to modify potential uterine leiomyomata risk.

Causal Relationship Between Sleep Traits and Hypothalamic-Pituitary-Target Gland Axis Function: A Mendelian Randomization Study

Background

In recent years, multiple observational studies have confirmed the association between sleep traits and various human physiopathological states. However, the causal relationship between sleep traits and hypothalamic-pituitary-target gland axis (HPTGA) function remains unknown.

Methods

We obtained summary statistics on sleep traits (insomnia, chronotype, and sleep duration (long and short)) from the UK Biobank database. Data related to the HPTGA functions were obtained from the publicly available database. Subsequently, a two-sample Mendelian randomization (MR) analysis was performed to investigate the causal relationship between different sleep traits and the HPTGA function. Reverse MR analysis was conducted to examine the direction of causality.

Results

The MR analysis results suggested that chronotype is associated with decreased levels of six hormones in HPTGA. Sleep duration was causally associated with decreased levels of free thyroxine and progesterone. Both long and short sleep durations are detrimental to the secretion of prolactin-releasing peptide, somatostatin, and plasma cortisol, while short sleep duration can promote progesterone secretion. After gender stratification, we found that female reproductive function is more susceptible to the influence of unfavorable sleep traits.

Conclusion

Our MR analysis indicated a significant causal association between chronotype and suppressed gonadal function in healthy adult humans, with no apparent gender-specific effect. Extreme sleep durations were also found to be detrimental to the maintenance of normal HPTGA secretion function. Compared to males, gonadal function in the female cohort is more susceptible to extreme sleep habits. Subsequent observational studies are urgently needed to confirm the underlying mechanisms.

Sex-Hormone-Binding Globulin Gene Polymorphisms and Breast Cancer Risk in Caucasian Women of Russia

In our work, the associations of GWAS (genome-wide associative studies) impact for sex-hormone-binding globulin (SHBG)-level SNPs with the risk of breast cancer (BC) in the cohort of Caucasian women of Russia were assessed. The work was performed on a sample of 1498 women (358 BC patients and 1140 control (non BC) subjects). SHBG correlated in previously GWAS nine polymorphisms such as rs780093 GCKR, rs17496332 PRMT6, rs3779195 BAIAP2L1, rs10454142 PPP1R21, rs7910927 JMJD1C, rs4149056 SLCO1B1, rs440837 ZBTB10, rs12150660 SHBG, and rs8023580 NR2F2 have been genotyped. BC risk effects of allelic and non-allelic SHBG-linked gene SNPs interactions were detected by regression analysis. The risk genetic factor for BC developing is an SHBG-lowering allele variant C rs10454142 PPP1R21 ([additive genetic model] OR = 1.31; 95%CI = 1.08-1.65; pperm = 0.024; power = 85.26%), which determines 0.32% of the cancer variance. Eight of the nine studied SHBG-related SNPs have been involved in cancer susceptibility as part of nine different non-allelic gene interaction models, the greatest contribution to which is made by rs10454142 PPP1R21 (included in all nine models, 100%) and four more SNPs-rs7910927 JMJD1C (five models, 55.56%), rs17496332 PRMT6 (four models, 44.44%), rs780093 GCKR (four models, 44.44%), and rs440837 ZBTB10 (four models, 44.44%). For SHBG-related loci, pronounced functionality in the organism (including breast, liver, fibroblasts, etc.) was predicted in silico, having a direct relationship through many pathways with cancer pathophysiology. In conclusion, our results demonstrated the involvement of SHBG-correlated genes polymorphisms in BC risk in Caucasian women in Russia.

Genetic regulation of testosterone level in overweight males from the Kazakh population and its association with hypogonadism

Male hypogonadism and erectile dysfunction in different populations are associated with excess body weight. A key aspect in most studies is the metabolism of sexual hormones, primarily testosterone. At the same time, the binding protein sex hormone binding globulin (SHBG) can play a large role, as it determines the ratio of total and bioavailable testosterone in blood, i.e. both the hormone content and level of its production. Recent research has identified common mutations that affect SHBG levels, such as the rs727428 polymorphic locus, which is associated with alterations in histone protein function, affecting the regulation of ribonucleic acid (RNA) protein SHBG synthesis. Similar relationships have been observed for prevalent mutations, including rs5934505 and rs10822184, in diverse populations. This study involved 300 individuals of Kazakh nationality from the Eastern Kazakhstan region, examining three polymorphic variants of the SHBG gene (rs727428, rs5934505, and rs10822184). The participants were categorized into three groups: individuals with hypogonadism and obesity (group 1, n=85), those with excess body weight but no hypogonadism (group 2, n=70), and individuals with neither excess body weight nor hypogonadism (group 3, n=145). The frequency of mutant gene alleles impacting GPS (SHBG) synthesis in the Kazakh population was notably high, comparable to European and South-East Asian populations. However, the association between excess body weight and these mutations exhibited varying patterns. Hypogonadism was linked to decreased GPS levels, strongly correlating with total testosterone but not bioavailable testosterone. The retention of sexual functions in overweight men was not always directly related to BMI levels and GPS concentrations.

Overlapping pathogenic de novo CNVs in neurodevelopmental disorders and congenital anomalies impacting constraint genes regulating early development

Neurodevelopmental disorders (NDDs) and congenital anomalies (CAs) are rare disorders with complex etiology. In this study, we investigated the less understood genomic overlap of copy number variants (CNVs) in two large cohorts of NDD and CA patients to identify de novo CNVs and candidate genes associated with both phenotypes. We analyzed clinical microarray CNV data from 10,620 NDD and 3176 CA cases annotated using Horizon platform of GenomeArc Analytics and applied rigorous downstream analysis to evaluate overlapping genes from NDD and CA CNVs. Out of 13,796 patients, only 195 cases contained 218 validated de novo CNVs. Eighteen percent (31/170) de novo CNVs in NDD cases and 40% (19/48) de novo CNVs in CA cases contained genomic overlaps impacting developmentally constraint genes. Seventy-nine constraint genes (10.1% non-OMIM entries) were found to have significantly enriched genomic overlap within rare de novo pathogenic deletions (P value = 0.01, OR = 1.58) and 45 constraint genes (13.3% non-OMIM entries) within rare de novo pathogenic duplications (P value = 0.01, OR = 1.97). Analysis of spatiotemporal transcriptome demonstrated both pathogenic deletion and duplication genes to be highly expressed during the prenatal stage in human developmental brain (P value = 4.95 X 10-6). From the list of overlapping genes, EHMT1, an interesting known NDD gene encompassed pathogenic deletion CNVs from both NDD and CA patients, whereas FAM189A1, and FSTL5 are new candidate genes from non-OMIM entries. In summary, we have identified constraint overlapping genes from CNVs (including de novo) in NDD and CA patients that have the potential to play a vital role in common disease etiology.

Age-related loss of chromosome Y is associated with levels of sex hormone binding globulin and clonal hematopoiesis defined by TET2, TP53, and CBL mutations

Mosaic loss of the Y-chromosome (LOY) in peripheral blood leukocytes is the most common somatic alteration in men and linked to wide range of malignant and nonmalignant conditions. LOY is associated with age, smoking, and constitutional genetics. Here, we aimed to assess the relationships between LOY, serum biomarkers, and clonal hematopoiesis (CH). LOY in U.K. Biobank was strongly associated with levels of sex hormone binding globulin (SHBG), a key regulator of testosterone bioavailability. Mendelian randomization suggested a causal effect of SHBG on LOY but there was no evidence for an effect of LOY on SHBG. In contrast, age-related CH defined by somatic driver mutations was not associated with SHBG but was associated with LOY at clonal fractions above 30%. TET2, TP53, and CBL mutations were enriched in LOY cases, but JAK2 V617F was depleted. Our findings thus identify independent relationships between LOY, sex hormone levels, and CH.

Women's Reproductive Milestones and Cardiovascular Disease Risk: A Review of Reports and Opportunities From the CARDIA Study

In 1985 to 1986, the CARDIA (Coronary Artery Risk Development in Young Adults) study enrolled 5115 Black or White participants, including 2788 women, aged 18 to 30 years. Over the following 35 years, the CARDIA study amassed extensive longitudinal data on women's reproductive milestones, spanning menarche to menopause. Although not initially conceived as a study of women's health, >75 CARDIA study publications address relationships between reproductive factors and events with cardiovascular and metabolic risk factors, subclinical and clinical cardiovascular disease, and social determinants of health. The CARDIA study was one of the earliest population-based reports to note Black-White differences in age at menarche and associations with cardiovascular risk factors. Adverse pregnancy outcomes, particularly gestational diabetes and preterm birth, have been assessed along with postpartum behaviors, such as lactation. Existing studies have examined risk factors for adverse pregnancy outcomes and lactation, as well as their relationship to future cardiovascular and metabolic risk factors, diagnoses, and subclinical atherosclerosis. Ancillary studies examining components of polycystic ovary syndrome and ovarian biomarkers, such as anti-Müllerian hormone, have facilitated examination of reproductive health in a population-based cohort of young adult women. As the cohort transitioned through menopause, examination of the importance of premenopausal cardiovascular risk factors along with menopause has improved our understanding of shared mechanisms. The cohort is now aged in the 50s to mid-60s, and women will begin to experience a greater number of cardiovascular events as well as other conditions, such as cognitive impairment. Thus, in the next decade, the CARDIA study will provide a unique resource for understanding how the women's reproductive life course epidemiology informs cardiovascular risk, as well as reproductive and chronological aging.

Association Between Sex Hormone-Binding Globulin, Atherogenic Indices of Plasma Among Young Sedentary Males

Background

Males are more likely than females to suffer from cardiovascular disease (CVD). So, sex hormones may modify these variations and affect the lipid profile. We examined the relationship between sex hormone-binding globulin (SHBG) and CVD risk factors among young males in this study.

Methods

Using a cross-sectional design, we measured total testosterone, SHBG, lipids, glucose, insulin, antioxidant parameters, and anthropometric factors in 48 young males in the age range of 18 to 40 years. Atherogenic indices of plasma were calculated. In this study, a partial correlation analysis was carried out to assess the relationship between SHBG and other variables after adjustment for confounders.

Results

According to the results of multivariable analyses adjusted for age and energy, SHBG had a negative correlation with total cholesterol (r = -.454, P =.010), low-density lipoprotein cholesterol (r = -.496, P =.005), quantitative insulin-sensitivity check index, and positive correlation with high-density lipoprotein cholesterol (r = .463, P =.009). No significant correlation was observed between SHBG and triglycerides (P >.05). Several atherogenic indices of plasma have a negative correlation with SHBG levels. These include Atherogenic Index of Plasma (r = -.474, P = .006), Castelli Risk Index (CRI)1 (r = -.581, P < .001), CRI2 (r = -.564, P = .001), and Atherogenic Coefficient (r = -.581, P < .001).

Conclusion

Among young men, high plasma SHBG was associated with reduced CVD risk factors, modified lipid profile and atherogenic ratios, and better glycemic markers. Therefore, reduced SHBG concentrations could be a prognostic marker of CVD among young sedentary males.

Integrated Computational Approaches for Inhibiting Sex Hormone-Binding Globulin in Male Infertility by Screening Potent Phytochemicals

Male infertility is significantly influenced by the plasma-protein sex hormone-binding globulin (SHBG). Male infertility, erectile dysfunction, prostate cancer, and several other male reproductive system diseases are all caused by reduced testosterone bioavailability due to its binding to SHBG. In this study, we have identified 345 phytochemicals from 200 literature reviews that potentially inhibit severe acute respiratory syndrome coronavirus 2. Only a few studies have been done using the SARS-CoV-2 inhibitors to identify the SHBG inhibitor, which is thought to be the main protein responsible for male infertility. In virtual-screening and molecular-docking experiments, cryptomisrine, dorsilurin E, and isoiguesterin were identified as potential SHBG inhibitors with binding affinities of -9.2, -9.0, and -8.8 kcal/mol, respectively. They were also found to have higher binding affinities than the control drug anastrozole (-7.0 kcal/mol). In addition to favorable pharmacological properties, these top three phytochemicals showed no adverse effects in pharmacokinetic evaluations. Several molecular dynamics simulation profiles' root-mean-square deviation, radius of gyration, root-mean-square fluctuation, hydrogen bonds, and solvent-accessible surface area supported the top three protein-ligand complexes' better firmness and stability than the control drug throughout the 100 ns simulation period. These combinatorial drug-design approaches indicate that these three phytochemicals could be developed as potential drugs to treat male infertility.

LSD1/PRMT6-targeting gene therapy to attenuate androgen receptor toxic gain-of-function ameliorates spinobulbar muscular atrophy phenotypes in flies and mice

Spinobulbar muscular atrophy (SBMA) is caused by CAG expansions in the androgen receptor gene. Androgen binding to polyQ-expanded androgen receptor triggers SBMA through a combination of toxic gain-of-function and loss-of-function mechanisms. Leveraging cell lines, mice, and patient-derived specimens, we show that androgen receptor co-regulators lysine-specific demethylase 1 (LSD1) and protein arginine methyltransferase 6 (PRMT6) are overexpressed in an androgen-dependent manner specifically in the skeletal muscle of SBMA patients and mice. LSD1 and PRMT6 cooperatively and synergistically transactivate androgen receptor, and their effect is enhanced by expanded polyQ. Pharmacological and genetic silencing of LSD1 and PRMT6 attenuates polyQ-expanded androgen receptor transactivation in SBMA cells and suppresses toxicity in SBMA flies, and a preclinical approach based on miRNA-mediated silencing of LSD1 and PRMT6 attenuates disease manifestations in SBMA mice. These observations suggest that targeting overexpressed co-regulators can attenuate androgen receptor toxic gain-of-function without exacerbating loss-of-function, highlighting a potential therapeutic strategy for patients with SBMA.

Statistical methods for cis-Mendelian randomization with two-sample summary-level data

Mendelian randomization (MR) is the use of genetic variants to assess the existence of a causal relationship between a risk factor and an outcome of interest. Here, we focus on two-sample summary-data MR analyses with many correlated variants from a single gene region, particularly on cis-MR studies which use protein expression as a risk factor. Such studies must rely on a small, curated set of variants from the studied region; using all variants in the region requires inverting an ill-conditioned genetic correlation matrix and results in numerically unstable causal effect estimates. We review methods for variable selection and estimation in cis-MR with summary-level data, ranging from stepwise pruning and conditional analysis to principal components analysis, factor analysis, and Bayesian variable selection. In a simulation study, we show that the various methods have comparable performance in analyses with large sample sizes and strong genetic instruments. However, when weak instrument bias is suspected, factor analysis and Bayesian variable selection produce more reliable inferences than simple pruning approaches, which are often used in practice. We conclude by examining two case studies, assessing the effects of low-density lipoprotein-cholesterol and serum testosterone on coronary heart disease risk using variants in the HMGCR and SHBG gene regions, respectively.

The performance of multi-gene panels for breast/ovarian cancer predisposition

BRCA1 and BRCA2 are the most mutated genes in breast cancer. We analyzed 48 breast cancer subjects using two methods that differ in terms of number of genes investigated and strategy used (primers: Panel A - 12 genes - vs probes: Panel B - 48 genes). Both the panels and procedures identified "pathogenic" or "likely pathogenic" variants in TP53, ATM, CHEK2 and BARD1 besides BRCA1 and BRCA2. Panel B identified two other putatively pathogenic variants in RNASEL and in RAD50. Identification of variants other than the BRCA genes can be useful in patient management. A total of 121 variants were distributed within the 12 genes and were correctly detected by both panels. However, the number of calls without divergence, namely ± 0.10 difference of allelic frequency, was 78.3%, while calls with a divergence below 0.10 was 16.7%, thus indicating that only 5% (n = 275) of 5,412 calls had a divergence above 0.10. Although these panels differ from each other, both are useful in different situations, particularly when patients should be tested for genes other than BRCA1/2 (as occurs in patients affected by a so called hereditary syndrome) or for therapeutic purposes.

Construction of copy number variation landscape and characterization of associated genes in a Bangladeshi cohort of neurodevelopmental disorders

Introduction: Copy number variations (CNVs) play a critical role in the pathogenesis of neurodevelopmental disorders (NDD) among children. In this study, we aim to identify clinically relevant CNVs, genes and their phenotypic characteristics in an ethnically underrepresented homogenous population of Bangladesh. Methods: We have conducted chromosomal microarray analysis (CMA) for 212 NDD patients with male to female ratio of 2.2:1.0 to identify rare CNVs. To identify candidate genes within the rare CNVs, gene constraint metrics [i.e., "Critical-Exon Genes (CEGs)"] were applied to the population data. Autism Diagnostic Observation Schedule-Second Edition (ADOS-2) was followed in a subset of 95 NDD patients to assess the severity of autism and all statistical tests were performed using the R package. Results: Of all the samples assayed, 12.26% (26/212) and 57.08% (121/212) patients carried pathogenic and variant of uncertain significance (VOUS) CNVs, respectively. While 2.83% (6/212) patients' pathogenic CNVs were found to be located in the subtelomeric regions. Further burden test identified females are significant carriers of pathogenic CNVs compared to males (OR = 4.2; p = 0.0007). We have observed an increased number of Loss of heterozygosity (LOH) within cases with 23.85% (26/109) consanguineous parents. Our analyses on imprinting genes show, 36 LOH variants disrupting 69 unique imprinted genes and classified these variants as VOUS. ADOS-2 subset shows severe social communication deficit (p = 0.014) and overall ASD symptoms severity (p = 0.026) among the patients carrying duplication CNV compared to the CNV negative group. Candidate gene analysis identified 153 unique CEGs in pathogenic CNVs and 31 in VOUS. Of the unique genes, 18 genes were found to be in smaller (<1 MB) focal CNVs in our NDD cohort and we identified PSMC3 gene as a strong candidate gene for Autism Spectrum Disorder (ASD). Moreover, we hypothesized that KMT2B gene duplication might be associated with intellectual disability. Conclusion: Our results show the utility of CMA for precise genetic diagnosis and its integration into the diagnosis, therapy and management of NDD patients.

Serum sex hormone-binding globulin is a mediator of the association between intrahepatic lipid content and type 2 diabetes: the Maastricht Study

AIMS/HYPOTHESIS

Serum sex hormone-binding globulin (SHBG) has been proposed to act as a hepatokine that contributes to the extrahepatic complications observed in non-alcoholic fatty liver disease (NAFLD). However, it remains uncertain whether serum SHBG mediates the association between intrahepatic lipids (IHL) and type 2 diabetes. Therefore, we studied whether, and to what extent, serum SHBG mediates the association between IHL content and type 2 diabetes.

METHODS

We used cross-sectional data from the Maastricht Study (n=1554), a population-based cohort study with oversampling of individuals with type 2 diabetes. Type 2 diabetes status was assessed by oral glucose tolerance test, and IHL content was measured using 3T Dixon MRI. Mediation analyses were performed to assess the role of serum SHBG in mediating the association between IHL content and type 2 diabetes.

RESULTS

IHL content was significantly associated with type 2 diabetes in women and men (OR 1.08 [95% CI 1.04, 1.14] and OR 1.12 [95% CI 1.08, 1.17], respectively). Serum SHBG significantly mediated the association between IHL content and type 2 diabetes. The contribution of serum SHBG was higher in women (OR 1.04 [95% CI 1.02, 1.07]; proportion mediated 50.9% [95% CI 26.7, 81.3]) than in men (OR 1.02 [95% CI 1.01, 1.03]; proportion mediated 17.2% [95% CI 9.6, 27.6]). Repeat analyses with proxies of type 2 diabetes and adjustment for covariates did not substantially affect the results.

CONCLUSIONS/INTERPRETATION

In this large-scale population-based cohort study, serum SHBG was found to be a mediator of the association between IHL content and type 2 diabetes. These findings extend our understanding of the potential mechanisms by which NAFLD is a risk factor for type 2 diabetes, and further elaborate on the role of SHBG as a hepatokine.

Genome-Wide Association Study Revealed the Effect of rs312715211 in ZNF652 Gene on Abdominal Fat Percentage of Chickens

Abdominal fat percentage (AFP) is an important economic trait in chickens. Intensive growth selection has led to the over-deposition of abdominal fat in chickens, but the genetic basis of AFP is not yet clear. Using 520 female individuals from selection and control lines of Jingxing yellow chicken, we investigated the genetic basis of AFP using a genome-wide association study (GWAS) and fixation indices (F_ST). A 0.15 MB region associated with AFP was located on chromosome 27 and included nine significant single nucleotide polymorphisms (SNPs), which could account for 3.34-5.58% of the phenotypic variation. In addition, the π value, genotype frequency, and dual-luciferase results identified SNP rs312715211 in the intron region of ZNF652 as the key variant. The wild genotype was associated with lower AFP and abdominal fat weight (AFW), but higher body weight (BW). Finally, annotated genes based on the top 1% SNPs were used to investigate the physiological function of ZNF652. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis suggested that ZNF652 may reduce AFW and BW in broilers through the TGF-β1/SMad2/3 and MAPK/FoxO pathways via EGFR and TGFB1. Our findings elucidated the genetic basis of chicken AFP, rs312715211 on the ZNF652 gene, which can affect BW and AFW and was the key variant associated with AFP. These data provide new insight into the genetic mechanism underlying AF deposition in chickens and could be beneficial in breeding chickens for AF.

Usefulness of routine assessment of free testosterone for the diagnosis of functional male hypogonadism

OBJECTIVE

To investigate whether routine assessment of free testosterone improves the diagnostic accuracy of functional hypogonadism.

METHODS

Total and free testosterone (calculated on SHBG levels) were determined in 188 patients with sexual symptoms and 184 with infertility.

RESULTS

Hypogonadism (calculated free testosterone <63 pg/ml) was found in 47/188 (25.0%) patients with sexual symptoms and in 21/184 (11.4%) with infertility. Total testosterone determination misdiagnosed hypogonadism in 8.4% (12/143) of men with sexual symptoms and in 2% (3/152) with infertility. In subjects with borderline total testosterone, only 24.7% (19/77) had hypogonadism confirmed by free testosterone levels. Free testosterone levels significantly correlated with age, haematocrit, gonadotropins, gynecomastia, BMI, and number of co-morbidities, whereas total testosterone associated only with the latter two. Furthermore, age, haematocrit, BMI, and the presence of erectile dysfunction and of low libido were significantly different between men with normal and low free testosterone, whereas only BMI and low libido were significantly different between patients with normal and low total testosterone.

CONCLUSION

Routine assessment of free testosterone allows a more accurate diagnosis of functional hypogonadism, especially in men with sexual symptoms. Free testosterone levels associate with clinical and biochemical parameters of androgen deficiency better than total testosterone levels.

Role of sex hormone-binding globulin in the free hormone hypothesis and the relevance of free testosterone in androgen physiology

According to the free hormone hypothesis, biological activity of a certain hormone is best reflected by free rather than total hormone concentrations. A crucial element in this theory is the presence of binding proteins, which function as gatekeepers for steroid action. For testosterone, tissue exposure is governed by a delicate equilibrium between free and total testosterone which is determined through interaction with the binding proteins sex hormone-binding globulin and albumin. Ageing, genetics and various pathological conditions influence this equilibrium, hereby possibly modulating hormonal exposure to the target tissues. Despite ongoing controversy on the subject, strong evidence from recent in vitro, in vivo and human experiments emphasizes the relevance of free testosterone. Currently, however, clinical possibilities for free hormone diagnostics are limited. Direct immunoassays are inaccurate, while gold standard liquid chromatography with tandem mass spectrometry (LC-MS/MS) coupled equilibrium dialysis is not available for clinical routine. Calculation models for free testosterone, despite intrinsic limitations, provide a suitable alternative, of which the Vermeulen calculator is currently the preferred method. Calculated free testosterone is indeed associated with bone health, frailty and other clinical endpoints. Moreover, the added value of free testosterone in the clinical diagnosis of male hypogonadism is clearly evident. In suspected hypogonadal men in whom borderline low total testosterone and/or altered sex hormone-binding globulin levels are detected, the determination of free testosterone avoids under- and overdiagnosis, facilitating adequate prescription of hormonal replacement therapy. As such, free testosterone should be integrated as a standard biochemical parameter, on top of total testosterone, in the diagnostic workflow of male hypogonadism.

Mendelian randomization analyses of 23 known and suspected risk factors and biomarkers for breast cancer overall and by molecular subtypes

Many risk factors have been identified for breast cancer. The potential causality for some of them remains uncertain, and few studies have comprehensively investigated these associations by molecular subtypes. We performed a two-sample Mendelian randomization (MR) study to evaluate potential causal associations of 23 known and suspected risk factors and biomarkers with breast cancer risk overall and by molecular subtypes using data from the Breast Cancer Association Consortium. The inverse-variance weighted method was used to estimate odds ratios (OR) and 95% confidence interval (CI) for association of each trait with breast cancer risk. Significant associations with breast cancer risk were found for 15 traits, including age at menarche, age at menopause, body mass index, waist-to-hip ratio, height, physical activity, cigarette smoking, sleep duration, and morning-preference chronotype, and six blood biomarkers (estrogens, insulin-like growth factor-1, sex hormone-binding globulin [SHBG], telomere length, HDL-cholesterol and fasting insulin). Noticeably, an increased circulating SHBG was associated with a reduced risk of estrogen receptor (ER)-positive cancer (OR = 0.83, 95% CI: 0.73-0.94), but an elevated risk of ER-negative (OR = 1.12, 95% CI: 0.93-1.36) and triple negative cancer (OR = 1.19, 95% CI: 0.92-1.54) (P_{heterogeneity}  = 0.01). Fasting insulin was most strongly associated with an increased risk of HER2-negative cancer (OR = 1.94, 95% CI: 1.18-3.20), but a reduced risk of HER2-enriched cancer (OR = 0.46, 95% CI: 0.26-0.81) (P_{heterogeneity}  = 0.006). Results from sensitivity analyses using MR-Egger and MR-PRESSO were generally consistent. Our study provides strong evidence supporting potential causal associations of several risk factors for breast cancer and suggests potential heterogeneous associations of SHBG and fasting insulin levels with subtypes of breast cancer.

Serum sex hormone-binding globulin levels are reduced and inversely associated with intrahepatic lipid content and saturated fatty acid fraction in adult patients with glycogen storage disease type 1a

PURPOSE

De novo lipogenesis has been inversely associated with serum sex hormone-binding globulin (SHBG) levels. However, the directionality of this association has remained uncertain. We, therefore, studied individuals with glycogen storage disease type 1a (GSD1a), who are characterized by a genetic defect in glucose-6-phosphatase resulting in increased rates of de novo lipogenesis, to assess the downstream effect on serum SHBG levels.

METHODS

A case-control study comparing serum SHBG levels in patients with GSD1a (n = 10) and controls matched for age, sex, and BMI (n = 10). Intrahepatic lipid content and saturated fatty acid fraction were quantified by proton magnetic resonance spectroscopy.

RESULTS

Serum SHBG levels were statistically significantly lower in patients with GSD1a compared to the controls (p = 0.041), while intrahepatic lipid content and intrahepatic saturated fatty acid fraction-a marker of de novo lipogenesis-were significantly higher in patients with GSD1a (p = 0.001 and p = 0.019, respectively). In addition, there was a statistically significant, inverse association of intrahepatic lipid content and saturated fatty acid fraction with serum SHBG levels in patients and controls combined (β: - 0.28, 95% CI: - 0.47;- 0.09 and β: - 0.02, 95% CI: - 0.04;- 0.01, respectively).

CONCLUSION

Patients with GSD1a, who are characterized by genetically determined higher rates of de novo lipogenesis, have lower serum SHBG levels than controls.

Association of Prudent, Western, and Alternate Healthy Eating Index (AHEI-2010) dietary patterns with serum testosterone and sex hormone binding globulin levels in men

PURPOSE

The association of dietary patterns with testosterone (T) and sex hormone binding globulin (SHBG) levels remains unclear. We investigated the associations of dietary patterns with T and SHBG levels to determine whether these associations vary by obesity status.

METHODS

A cross-sectional analysis was conducted in 1376 middle-aged (≥ 40 years old) men of the Health Professionals Follow-up Study. Prudent (rich in whole grains and dietary fiber) and Western (rich in red meat and refined grains) diet scores were identified using principal component analysis. The Alternate Healthy Eating Index 2010 (AHEI-2010) score, a measure of overall diet quality, was defined based on foods and nutrients predictive of chronic disease risk.

RESULTS

We identified a weak inverse association between AHEI-2010 and T levels (P_trend = 0.07), but no associations with other dietary patterns. Null associations were observed between diet scores and SHBG. Obesity status appeared to modify the associations for the Prudent diet and AHEI-2010 with both T and SHBG (P_interaction ≤ 0.05). T levels were lower (Q1 vs. Q4, 4.23 vs. 3.38) and SHBG higher (Q1 vs. Q4, 48.6 vs. 64.3) with adherence to a more prudent diet among obese men (P_trends ≤ 0.05).

CONCLUSION

We observed a weak inverse association between AHEI-2010 and T levels. Null associations were identified for SHBG. Obesity status seemed to modulate associations of T and SHBG levels with diet scores, especially the AHEI-2010 and prudent diets. However, this research question warrants further investigation in prospective studies.

Pyruvate kinase L/R links metabolism dysfunction to neuroendocrine differentiation of prostate cancer by ZBTB10 deficiency

Neuroendocrine differentiation (NED) frequently occurs in androgen-deprivation therapy (ADT)-resistant prostate cancer (PCa) and is typically associated with metabolic pathway alterations, acquisition of lineage plasticity, and malignancy. There is no conventional therapeutic approach for PCa patients with NED pathologic features because the molecular targets are unknown. Here, we evaluated the regulatory mechanism of NED-associated metabolic reprogramming induced by ADT. We detected that the loss of the androgen-responsive transcription factor, zinc finger, and BTB domain containing 10 (ZBTB10), can activate pyruvate kinase L/R (PKLR) to enhance a NED response that is associated with glucose uptake by PCa cells. PKLR exhibits a tumor-promoting effect in PCa after ADT, but ZBTB10 can compensate for the glucose metabolism and NED capacity of PKLR through the direct transcriptional downregulation of PKLR. Targeting PKLR by drug repurposing with FDA-approved compounds can reduce the aggressiveness and NED of ADT-resistant PCa. We demonstrated that PKLR acts as a modulator to activate NED in PCa enhancement by loss of ZBTB10, thereby enabling PCa cells to mount a glycolysis response essential for therapeutic resistance. Our findings highlight the broad relation between NED and metabolic dysfunction to provide gene expression-based biomarkers for NEPC treatment.

Genetically predicted sex hormone binding globulin and ischemic heart disease in men and women: a univariable and multivariable Mendelian randomization study

Men are more vulnerable to ischemic heart disease (IHD) than women, possibly due to testosterone. Correspondingly, sex hormone binding globulin (SHBG) which lowers circulating testosterone might protect men against IHD. SHBG may also affect IHD independent of testosterone, which has not previously been examined. To assess the sex-specific role of SHBG in IHD, in univariable Mendelian randomization (MR), we used sex-specific, genome-wide significant genetic variants to predict SHBG, and examined their association with IHD in the UK Biobank. We also replicated using genetic instruments from Japanese men and applied to Biobank Japan. To assess the role of SHGB independent of testosterone in men, we used multivariable MR controlling for testosterone. Genetically predicted SHBG was associated with lower IHD risk in men [odds ratio (OR) 0.78 per standard deviation, 95% confidence interval (CI) 0.70 to 0.87], and the association was less clear in women. The estimates were similar in Japanese. The inverse association remained after controlling for testosterone in men (OR 0.79, 95% CI 0.71 to 0.88). SHBG might lower the risk of IHD in men, with a role independent of testosterone. Exploring intervention strategies that increase SHBG is important for targeting IHD treatments.

Genome-wide Association Study of Estradiol Levels and the Causal Effect of Estradiol on Bone Mineral Density

CONTEXT

Estradiol is the primary female sex hormone and plays an important role for skeletal health in both sexes. Several enzymes are involved in estradiol metabolism, but few genome-wide association studies (GWAS) have been performed to characterize the genetic contribution to variation in estrogen levels.

OBJECTIVE

Identify genetic loci affecting estradiol levels and estimate causal effect of estradiol on bone mineral density (BMD).

DESIGN

We performed GWAS for estradiol in males (n = 147 690) and females (n = 163 985) from UK Biobank. Estradiol was analyzed as a binary phenotype above/below detection limit (175 pmol/L). We further estimated the causal effect of estradiol on BMD using Mendelian randomization.

RESULTS

We identified 14 independent loci associated (P < 5 × 10-8) with estradiol levels in males, of which 1 (CYP3A7) was genome-wide and 7 nominally (P < 0.05) significant in females. In addition, 1 female-specific locus was identified. Most loci contain functionally relevant genes that have not been discussed in relation to estradiol levels in previous GWAS (eg, SRD5A2, which encodes a steroid 5-alpha reductase that is involved in processing androgens, and UGT3A1 and UGT2B7, which encode enzymes likely to be involved in estradiol elimination). The allele that tags the O blood group at the ABO locus was associated with higher estradiol levels. We identified a causal effect of high estradiol levels on increased BMD in both males (P = 1.58 × 10-11) and females (P = 7.48 × 10-6).

CONCLUSION

Our findings further support the importance of the body's own estrogen to maintain skeletal health in males and in females.

Impact of sex hormone-binding globulin on the human phenome

Background: Sex hormone-binding globulin (SHBG) is a circulating glycoprotein and a regulator of sex hormone levels, which has been shown to influence various traits and diseases. The molecular nature of SHBG makes it a feasible target for preventative or therapeutic interventions. A systematic study of its effects across the human phenome may uncover novel associations. Methods: We used a Mendelian randomization phenome-wide association study (MR-pheWAS) approach to systematically appraise the potential functions of SHBG while reducing potential biases such as confounding and reverse causation common to the literature. We searched for potential causal effects of SHBG in UK Biobank (N = 334 977) and followed-up our top findings using two-sample MR analyses to evaluate whether estimates may be biased due to horizontal pleiotropy. Results: Results of the MR-pheWAS across over 21 000 outcome phenotypes identified 12 phenotypes associated with genetically elevated SHBG after Bonferroni correction for multiple testing. Follow-up analysis using two-sample MR indicated the associations of increased natural log SHBG with higher impedance of the arms and whole body, lower pulse rate, lower bone density, higher odds of hip replacement, lower odds of high cholesterol or cholesterol medication use and higher odds of gallbladder removal. Conclusions: Our systematic MR-pheWAS of SHBG, which was comprehensive to the range of phenotypes available in UK Biobank, suggested that higher circulating SHBG affects the body impedance, bone density and cholesterol levels, among others. These phenotypes should be prioritized in future studies aiming to investigate the biological effects of SHBG or develop targets for therapeutic intervention.

Sex hormone-binding globulin: biomarker and hepatokine?

Over the past decade, there have been important breakthroughs in our understanding of the regulation and function of sex hormone-binding globulin (SHBG). A recent genome-wide association and Mendelian randomization study has provided new insights at the population level. Thorough study of genetic variants affecting serum SHBG has identified de novo lipogenesis as one of the mechanistic links between the metabolic syndrome and reduced serum SHBG levels in humans. Furthermore, careful deduction of the Mendelian randomization results suggests a direct, causal role for SHBG in the pathogenesis of type 2 diabetes, as a hepatokine, in women. These findings prompt the development of SHBG-raising therapies as a means to prevent or treat disorders such as type 2 diabetes and polycystic ovary syndrome.

Circulating Levels of Testosterone, Sex Hormone Binding Globulin and Colorectal Cancer Risk: Observational and Mendelian Randomization Analyses

BACKGROUND

Epidemiologic studies evaluating associations between sex steroid hormones and colorectal cancer risk have yielded inconsistent results. To elucidate the role of circulating levels of testosterone, and sex hormone-binding globulin (SHBG) in colorectal cancer risk, we conducted observational and Mendelian randomization (MR) analyses.

METHODS

The observational analyses included 333,530 participants enrolled in the UK Biobank with testosterone and SHBG measured. HRs and 95% confidence intervals (CI) were estimated using multivariable Cox proportional hazards models. For MR analyses, genetic variants robustly associated with hormone levels were identified and their association with colorectal cancer (42,866 cases/42,752 controls) was examined using two-sample MR.

RESULTS

In the observational analysis, there was little evidence that circulating levels of total testosterone were associated with colorectal cancer risk; the MR analyses showed a greater risk for women (OR per 1-SD = 1.09; 95% CI, 1.01-1.17), although pleiotropy may have biased this result. Higher SHBG concentrations were associated with greater colorectal cancer risk for women (HR per 1-SD = 1.16; 95% CI, 1.05-1.29), but was unsupported by the MR analysis. There was little evidence of associations between free testosterone and colorectal cancer in observational and MR analyses.

CONCLUSIONS

Circulating concentrations of sex hormones are unlikely to be causally associated with colorectal cancer. Additional experimental studies are required to better understand the possible role of androgens in colorectal cancer development.

IMPACT

Our results from large-scale analyses provide little evidence for sex hormone pathways playing a causal role in colorectal cancer development.See related commentary by Hang and Shen, p. 1302.

Patterns of recent natural selection on genetic loci associated with sexually differentiated human body size and shape phenotypes

Levels of sex differences for human body size and shape phenotypes are hypothesized to have adaptively reduced following the agricultural transition as part of an evolutionary response to relatively more equal divisions of labor and new technology adoption. In this study, we tested this hypothesis by studying genetic variants associated with five sexually differentiated human phenotypes: height, body mass, hip circumference, body fat percentage, and waist circumference. We first analyzed genome-wide association (GWAS) results for UK Biobank individuals (~194,000 females and ~167,000 males) to identify a total of 114,199 single nucleotide polymorphisms (SNPs) significantly associated with at least one of the studied phenotypes in females, males, or both sexes (P<5x10^-8). From these loci we then identified 3,016 SNPs (2.6%) with significant differences in the strength of association between the female- and male-specific GWAS results at a low false-discovery rate (FDR<0.001). Genes with known roles in sexual differentiation are significantly enriched for co-localization with one or more of these SNPs versus SNPs associated with the phenotypes generally but not with sex differences (2.73-fold enrichment; permutation test; P = 0.0041). We also confirmed that the identified variants are disproportionately associated with greater phenotype effect sizes in the sex with the stronger association value. We then used the singleton density score statistic, which quantifies recent (within the last ~3,000 years; post-agriculture adoption in Britain) changes in the frequencies of alleles underlying polygenic traits, to identify a signature of recent positive selection on alleles associated with greater body fat percentage in females (permutation test; P = 0.0038; FDR = 0.0380), directionally opposite to that predicted by the sex differences reduction hypothesis. Otherwise, we found no evidence of positive selection for sex difference-associated alleles for any other trait. Overall, our results challenge the longstanding hypothesis that sex differences adaptively decreased following subsistence transitions from hunting and gathering to agriculture.

There is uncertainty regarding the evolutionary history of human sex differences for quantitative body size and shape phenotypes. In this study we identified thousands of genetic loci that differentially impact body size and shape trait variation between females and males using a large sample of UK Biobank individuals. After confirming the biological plausibility of these loci, we used a population genomics approach to study the recent (over the past ~3,000 years) evolutionary histories of these loci in this population. We observed significant increases in the frequencies of alleles associated with greater body fat percentage in females. This result is contradictory to longstanding hypotheses that sex differences have adaptively decreased following subsistence transitions from hunting and gathering to agriculture.

Genetically Predicted Sex Hormone-Binding Globulin and Bone Mineral Density: A Mendelian Randomization Study

Previous observational studies have identified various risk factors associated with the development of osteoporosis, including sex hormone-binding globulin (SHBG). The aim of this study was to determine the potential causal effects of circulating SHBG concentrations on bone mineral density (BMD). Two-sample Mendelian randomization (MR) approach was applied in analyses. From summary-level data of genome-wide association studies (GWAS), we selected 11 single-nucleotide polymorphisms (SNPs) associated with SHBG levels as instrumental variable, and used summary statistics for BMD at forearm (FA) (n = 8143), femoral neck (FN) (n = 32,735), lumbar spine (LS) (n = 28,498) and heel (HL) (n = 394,929), and total-body BMD of different age-stages (15 or less, 15-30, 30-45, 45-60, 60 or more years old) (n = 67,358). Inverse causal associations was observed between SHBG levels and FA BMD (Effect = - 0.26; 95% CI - 0.49 to - 0.04; P = 0.022), HL eBMD (Effect = - 0.09; 95% CI - 0.12 to - 0.06; P = 3.19 × 10^-9), and total-body BMD in people aged 45-60 years (Effect = - 0.16; 95% CI - 0.31 to - 2.4 × 10^-3; P = 0.047) and over 60 years (Effect = - 0.19; 95% CI - 0.33 to - 0.05; P = 0.006). Our study demonstrates that circulating SHBG concentrations are inversely associated with FA and HL eBMD, and total-body BMD in people aged over 45 years, suggesting that the role of SHBG in the development of osteoporosis might be affected by chronological age of patients and skeletal sites.

Sex-specific Associations of Sex Hormone Binding Globulin with CKD and Kidney Function: A Univariable and Multivariable Mendelian Randomization Study in the UK Biobank

BACKGROUND

Kidney function declines faster in men. Testosterone levels may mediate the sex disparity. Correspondingly, levels of sex hormone binding globulin (SHBG), which modulates sex hormones, might also be relevant to the lower kidney function in men. The sex-specific role of SHBG is unclear.

METHODS

A sex-specific, Mendelian randomization (MR) study provided unconfounded estimates of SHBG levels among the United Kingdom Biobank population. Univariable MR applied 357 single nucleotide polymorphisms (SNPs) in men and 359 SNPs in women. These published SNPs strongly (P<5×10^-8) predict SHBG level. They were profiled in 179,916 white British men (6016 patients with CKD) and 212,079 white British women (5958 patients with CKD), to obtain the effect of SHBG on CKD, albuminuria, and eGFR. Multivariable MR controlling for testosterone was used to assess the effect of SHBG on CKD and kidney function independent of testosterone in men.

RESULTS

Genetically predicted higher SHBG was associated with a lower risk of CKD in men (odds ratio [OR], 0.78 per SD; 95% confidence interval [95% CI], 0.65 to 0.93) but had no benefit in women. The effect in men remained in multivariable MR, allowing for testosterone (OR, 0.61; 95% CI, 0.45 to 0.82).

CONCLUSIONS

Genetically predicted higher SHBG was associated with a lower risk of CKD and better kidney function in men, but not in women, suggesting that SHBG may play a role in CKD specifically in men. Identifying drivers of SHBG and the underlying pathways could provide new insights into CKD prevention and treatment.

Association between sex hormones regulation-related SNP rs12233719 and lung cancer risk among never-smoking Chinese women

BACKGROUND

The mechanism of rapidly increased non-small cell lung cancer (NSCLC) among never-smoking Chinese women has not been elucidated. Ovarian sex steroid hormones have been suggested to counteract lung cancer development, and sex hormone-binding globulin (SHBG) is essential in sex hormones regulation. This study aims to exploring single nucleotide polymorphisms (SNPs) in genomic regions associated with SHBG concentrations that contributed to never-smoking female NSCLC.

METHODS

Candidate genes were selected by a genome-wide association (GWAS) meta-analysis and gene expression profiles of never-smoking NSCLC of Chinese women. The candidate SNPs limited to common minor allele frequency (MAF), missense variant, ethnic heterogeneous distribution, and SNPs were genotyped using the TaqMan method. A two-stage case-control design was adopted for exploration and validation of associations between candidate SNPs and risk of NSCLC. All participants were never-smoking Chinese women. Chi-square test and multivariate logistic regression were applied.

RESULTS

Beginning with 12 genomic regions associated with circulating SHBG concentrations and gene expression profiles from never-smoking NSCLC in Chinese women, candidate SNP rs12233719 and rs7439366 both located in candidate gene UGT₂ B_7, which may be related to circulating SHBG concentrations and cancer risk, were identified. A two-stage case-control study was conducted in Shenyang and Tianjin represented as the training stage and validation stage, respectively. Under the dominant model, compared to individuals with the wild G/G genotype, the adjusted OR of those with the T allele was 1.58 (95% CI: 1.15-2.16) in Chinese Shenyang training set, and was 1.49 (95% CI: 1.02-2.18) in Chinese Tianjin validation set, both accompanied with a significant trend relationship consistently. UGT2B7 was upregulated in female NSCLC patients' tumor tissues and was associated with a poor prognosis in NSCLC.

CONCLUSION

Our findings indicated that a sex hormones regulation-related SNP rs12233719 was associated with never-smoking female lung cancer risk, which might partially explain NSCLC-susceptibility in Chinese women.

GWAS of three molecular traits highlights core genes and pathways alongside a highly polygenic background

Genome-wide association studies (GWAS) have been used to study the genetic basis of a wide variety of complex diseases and other traits. We describe UK Biobank GWAS results for three molecular traits-urate, IGF-1, and testosterone-with better-understood biology than most other complex traits. We find that many of the most significant hits are readily interpretable. We observe huge enrichment of associations near genes involved in the relevant biosynthesis, transport, or signaling pathways. We show how GWAS data illuminate the biology of each trait, including differences in testosterone regulation between females and males. At the same time, even these molecular traits are highly polygenic, with many thousands of variants spread across the genome contributing to trait variance. In summary, for these three molecular traits we identify strong enrichment of signal in putative core gene sets, even while most of the SNP-based heritability is driven by a massively polygenic background.

Mendelian randomization for studying the effects of perturbing drug targets

Drugs whose targets have genetic evidence to support efficacy and safety are more likely to be approved after clinical development. In this paper, we provide an overview of how natural sequence variation in the genes that encode drug targets can be used in Mendelian randomization analyses to offer insight into mechanism-based efficacy and adverse effects. Large databases of summary level genetic association data are increasingly available and can be leveraged to identify and validate variants that serve as proxies for drug target perturbation. As with all empirical research, Mendelian randomization has limitations including genetic confounding, its consideration of lifelong effects, and issues related to heterogeneity across different tissues and populations. When appropriately applied, Mendelian randomization provides a useful empirical framework for using population level data to improve the success rates of the drug development pipeline.

Mendelian randomization for studying the effects of perturbing drug targets

Drugs whose targets have genetic evidence to support efficacy and safety are more likely to be approved after clinical development. In this paper, we provide an overview of how natural sequence variation in the genes that encode drug targets can be used in Mendelian randomization analyses to offer insight into mechanism-based efficacy and adverse effects. Large databases of summary level genetic association data are increasingly available and can be leveraged to identify and validate variants that serve as proxies for drug target perturbation. As with all empirical research, Mendelian randomization has limitations including genetic confounding, its consideration of lifelong effects, and issues related to heterogeneity across different tissues and populations. When appropriately applied, Mendelian randomization provides a useful empirical framework for using population level data to improve the success rates of the drug development pipeline.

Association Between Levels of Sex Hormones and Risk of Esophageal Adenocarcinoma and Barrett's Esophagus

BACKGROUND & AIMS

Esophageal adenocarcinoma (EAC) occurs most frequently in men. We performed a Mendelian randomization analysis to investigate whether genetic factors that regulate levels of sex hormones are associated with risk of EAC or Barrett's esophagus (BE).

METHODS

We conducted a Mendelian randomization analysis using data from patients with EAC (n = 2488) or BE (n = 3247) and control participants (n = 2127), included in international consortia of genome-wide association studies in Australia, Europe, and North America. Genetic risk scores or single-nucleotide variants were used as instrumental variables for 9 specific sex hormones. Logistic regression provided odds ratios (ORs) with 95% CIs.

RESULTS

Higher genetically predicted levels of follicle-stimulating hormones were associated with increased risks of EAC and/or BE in men (OR, 1.14 per allele increase; 95% CI, 1.01-1.27) and in women (OR, 1.28; 95% CI, 1.03-1.59). Higher predicted levels of luteinizing hormone were associated with a decreased risk of EAC in men (OR, 0.92 per SD increase; 95% CI, 0.87-0.99) and in women (OR, 0.93; 95% CI, 0.79-1.09), and decreased risks of BE (OR, 0.88; 95% CI, 0.77-0.99) and EAC and/or BE (OR, 0.89; 95% CI, 0.79-1.00) in women. We found no clear associations for other hormones studied, including sex hormone-binding globulin, dehydroepiandrosterone sulfate, testosterone, dihydrotestosterone, estradiol, progesterone, or free androgen index.

CONCLUSIONS

In a Mendelian randomization analysis of data from patients with EAC or BE, we found an association between genetically predicted levels of follicle-stimulating and luteinizing hormones and risk of BE and EAC.

Research progress on the relationship between sex hormone-binding globulin and male reproductive system diseases

Sex hormone-binding globulin, also known as testosterone-estradiol-binding globulin, is a multifunctional protein synthesised by hepatocytes. Sex hormone-binding globulin specifically binds and transports sex hormones to regulate plasma bioactive sex hormone levels and affects their bioavailability. As male sex hormone expression is dominated by testosterone, the binding of sex hormone-binding globulin with testosterone leads to the reduction in bioavailable testosterone, which cannot fulfil its physiological roles, thereby resulting in male infertility, erectile and gonadal dysfunction, prostate cancer and other male reproductive system diseases. Sex hormone-binding globulin may be involved in the pathogenesis of male reproductive system diseases, seriously affecting the quality of life of men. In this article, we review the association between sex hormone-binding globulin and male reproductive system diseases.

Associations between androgens and sexual function in premenopausal women: a cross-sectional study

BACKGROUND

Although clinicians often measure the serum concentration of androgens in premenopausal women presenting with sexual dysfunction, with some women given testosterone or dehydroepiandrosterone as treatment if their concentrations are low, whether androgens are determinants of sexual function in women of reproductive age is uncertain. We aimed to clarify the associations between androgens and sexual function in a community-based sample of non-health-care-seeking women.

METHODS

This is a substudy of the Grollo-Ruzzene cross-sectional study, which recruited women aged 18-39 years from eastern states in Australia (QLD, NSW, VIC). After providing consent, women completed an online survey that included the Profile of Female Secual Function (PFSF) questionnaire, and those who were who were not pregnant, breastfeeding, or using systemic steroids were asked to provide a blood sample. At sampling, women were asked the dates of their last menstrual bleed. Serum androgens was measured by liquid chromatography and tandem mass spectrometry and sex hormone binding globulin (SHBG) by immunoassay. Associations between androgens and domains of sexual function, assessed by the PFSF, were examined in participants with regular menstrual cycles. After univariable linear regression (model 1), age, BMI, stage of menstrual cycle, and smoking status were added to the model (model 2), and then parity, partner status, and psychotropic medication use (model 3).

FINDINGS

Of 6986 women who completed the online survey (surveys completed between Nov 11, 2016, and July 21, 2017), 3698 were eligible and 761 (20·6%) provided blood samples by Sept 30, 2017. Of those who provided a blood sample, 588 (77·3%) had regular menstrual cycles and were included in the analysis. Adjusting for age, BMI, cycle stage, smoking, parity, partner status, and psychoactive medication, sexual desire was positively associated with serum dehydroepiandrosterone (β-coefficient 3·39, 95% CI 0·65 to 6·03) and androstenedione (4·81, 0·16 to 9·12), and negatively with SHBG (-5.74, -9.54 to -1·90), each model explaining less than 4% of the variation in desire. Testosterone (6·00, 1·29 to 10·94) and androstenedione (6·05, 0·70 to 11·51) were significantly associated with orgasm, with the final models explaining less than 1% of the variation in orgasm. Significant associations were found between androstenedione (7·32, 0·93 to 13·08) and dehydroepiandrosterone (4·44, 0·86 to 7·95) and pleasure, and between testosterone and sexual self-image 5·87 (1·27 to 10·61), with inclusion of parity, partners status, and psychotropic drug use increasing the proportion of variation explained by each model to approximately 10%. There were no statistically significant associations between 11-oxygenated steroids and any PFSF domain, or between arousal or responsiveness and any hormone. No associations were seen between 11-oxygenated steroids and any sexual domain, or between arousal or responsiveness and any hormone.

INTERPRETATION

Associations between androgens and sexual function in premenopausal women are small, and their measurement offers no diagnostic use in this context. Further research to determine whether 11-ketoandrostenedione or 11-ketotestosterone are of clinical significance is warranted.

FUNDING

The Grollo-Ruzzene Foundation.

Testosterone replacement therapy: Pre-treatment sex hormone-binding globulin levels and age may identify clinical subgroups

BACKGROUND

Testosterone replacement therapy (TRT) improves health in some but not all men with type 2 diabetes (T2DM) and adult-onset testosterone deficiency (TD). Such heterogeneity is compatible with the concept of patient subgroups that respond differently to therapy.

OBJECTIVES

Use baseline SHBG and age to identify putative subgroups that demonstrate different responses in variables such as waist circumference and HbA1c following TRT.

MATERIALS AND METHODS

A randomized double-blind trial approach was used to recruit and randomize men with T2DM and adult-onset TD into placebo and TRT-treated groups. Multiple regression was used to study differences between groups.

RESULTS

Baseline SHBG and change in SHBG (∆SHBG) were inversely related in the TRT group. Both median values of SHBG and age mediated the effect of TRT on ∆SHBG depending on whether baseline values were ≤ or>median (28.1 nmol/L, 63 years, respectively). In men with both SHBG ≤ 28.1 nmol/L and age ≤ 63 years (subgroup 1), TRT was positively associated with ∆SHBG (c = 4.67, 95%CI 1.17-8.16, P = .010) while in those with SHBG > 28.1 nmol/L and age > 63.1 years (subgroup 4) the association was inverse (c = -7.07, 95%CI -11.64 to -2.49, P = .003). The association between TRT and change (∆) in waist circumference, HbA1c and International Index of Erectile Function (IIEF) score differed between subgroups; in subgroup 4 but not subgroup 1, the therapy was significantly associated with ∆waist circumference, ∆HbA1c and ∆IIEF.

DISCUSSION

Though the mechanism remains unclear, our finding of different responses to TRT in terms of change in waist circumference, HbA1c and IIEF score supports the concept of subgroups in men with T2DM and adult-onset TD.

CONCLUSION

Our approach may provide a basis for identifying men who will or will not derive benefit from TRT though a larger study is required.

Sex hormone-binding globulin and arthritis: a Mendelian randomization study

Background

Sex hormone-binding globulin (SHBG) has been reported to be a risk factor associated with the development of arthritis by previous observational studies more so of three common forms of arthritis: osteoarthritis (OA), rheumatoid arthritis (RA), and ankylosing spondylitis (AS). This study aimed to determine whether the concentrations of circulating SHBG are causally associated with the risk of OA, RA, and AS.

Methods

The two-sample Mendelian randomization (MR) approach was used for this study. The inverse-variance-weighted (IVW) method was used for the main analysis. Single-nucleotide polymorphisms (SNPs) associated with SHBG were selected from a large genome-wide association study (GWAS) of 28,837 European individuals. The summary statistics for OA, RA, and AS were extracted from the UK Biobank Resource (n = 361,141) and a GWAS dataset (n = 455,221).

Results

Positive causal associations were found between circulating SHBG concentrations and OA (effect = 1.086; 95% CI, 1.009 to 1.168; P = 0.027) and RA (effect = 1.003; 95% CI, 1.000 to 1.007; P = 0.047) in overall analyses. However, there was no evidence of association between SHBG levels and AS. Based on the stratification of skeletal sites, SHBG levels were found to be significantly associated with hip OA (effect = 1.423; 95% CI, 1.219 to 1.660; P = 7.753 × 10⁻⁶). However, this was not the case with knee OA.

Conclusions

There were positive causal effects of circulating SHBG on the development of OA and RA. Moreover, there was a site-specific association between SHBG and hip OA. Evidently, measurement of SHBG in serum could be valuable in the clinical assessment of arthritis especially in early screening and prevention of OA and RA. However, the mechanisms by which SHBG plays causal roles in the development of arthritis require further investigations.

Genome-wide association study of semen volume, sperm concentration, testis size, and plasma inhibin B levels

Semen quality is affected by environmental factors, endocrine function abnormalities, and genetic factors. A GWAS recently identified ERBB4 at 2q34 as a genetic locus associated with sperm motility. However, GWASs for human semen volume and sperm concentration have not been conducted. In addition, testis size also reportedly correlates with semen quality, and it is important to identify genes that affect testis size. Reproductive hormones also play an important role in spermatogenesis. To date, genetic loci associated with plasma testosterone, sex hormone-binding globulin (SHBG), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) levels have been identified using GWASs. However, GWASs have not identified any relevant loci for plasma inhibin B levels. We conducted a two-stage GWAS using 811 Japanese men in a discovery stage followed by a replication stage using an additional 721 Japanese men. The results of the discovery and replication stages were combined into a meta-analysis. After setting a suggestive significance threshold for P values < 5 × 10^-6　in the discovery stage, we identified ten regions with SNPs (semen volume: one, sperm concentration: three, testes size: two, and inhibin B: four). We selected only the most significant SNP in each region for replication genotyping. Combined discovery and replication results in the meta-analysis showed that the locus 12q21.31 associated with plasma inhibin B levels (rs11116724) had the most significant association (P = 5.7 × 10^-8). The LRRIQ1 and TSPAN19 genes are located in the 12q21.31 region. This study provides new susceptibility variants that contribute to plasma inhibin B levels.

Genetic Variation in Steroid and Xenobiotic Metabolizing Pathways and Enterolactone Excretion Before and After Flaxseed Intervention in African American and European American Women

BACKGROUND

Metabolism and excretion of the phytoestrogen enterolactone (ENL), which has been associated with breast cancer risk, may be affected by variation in steroid hormone and xenobiotic-metabolizing genes.

METHODS

We conducted a randomized, crossover flaxseed intervention study in 252 healthy, postmenopausal women [137 European ancestry (EA) and 115 African ancestry (AA)] from western New York. Participants were randomly assigned to maintain usual diet or consume 10 g/day ground flaxseed for 6 weeks. After a 2-month washout period, participants crossed over to the other diet condition for an additional 6 weeks. Urinary ENL excretion was measured by gas chromatography-mass spectrometry and 70 polymorphisms in 29 genes related to steroid hormone and xenobiotic metabolism were genotyped. Mixed additive genetic models were constructed to examine association of genetic variation with urinary ENL excretion at baseline and after the flaxseed intervention.

RESULTS

SNPs in several genes were nominally (P < 0.05) associated with ENL excretion at baseline and/or after intervention: ESR1, CYP1B1, COMT, CYP3A5, ARPC1A, BCL2L11, SHBG, SLCO1B1, and ZKSCAN5. A greater number of SNPs were associated among AA women than among EA women, and no SNPs were associated in both races. No SNP-ENL associations were statistically significant after correction for multiple comparisons.

CONCLUSIONS

Variation in several genes related to steroid hormone metabolism was associated with lignan excretion at baseline and/or after flaxseed intervention among postmenopausal women.

IMPACT

These findings may contribute to our understanding of the differences observed in urinary ENL excretion among AA and EA women and thus hormone-related breast cancer risk.

A genome-wide association study identifies FSHR rs2300441 associated with follicle-stimulating hormone levels

Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) play critical roles in female reproduction, while the underlying genetic basis is poorly understood. Genome-wide association studies (GWASs) of FSH and LH levels were conducted in 2590 Chinese females including 1882 polycystic ovary syndrome (PCOS) cases and 708 controls. GWAS for FSH level identified multiple variants at FSHR showing genome-wide significance with the top variant (rs2300441) located in the intron of FSHR. The A allele of rs2300441 led to a reduced level of FSH in the PCOS group (β = -.43, P = 6.70 × 10^-14 ) as well as in the control group (β = -.35, P = 6.52 × 10^-4 ). In the combined sample, this association was enhanced after adjusting for the PCOS status (before: β = -.38, P = 1.77 × 10^-13 ; after: β = -.42, P = 3.33 × 10^-16 ), suggesting the genetic effect is independent of the PCOS status. The rs2300441 explained sevenfold higher proportion of the FSH variance than the total variance explained by the two previously reported FSHR missense variants (rs2300441 R² = 1.40% vs rs6166 R² = 0.17%, rs6165 R² = 0.03%). GWAS for LH did not identify any genome-wide significant associations. In conclusion, we identified genome-wide significant association between variants in FSHR and circulating FSH first, with the top associated variant rs2300441 might be a primary contributor at the population level.

Using human genetics to understand the disease impacts of testosterone in men and women

Testosterone supplementation is commonly used for its effects on sexual function, bone health and body composition, yet its effects on disease outcomes are unknown. To better understand this, we identified genetic determinants of testosterone levels and related sex hormone traits in 425,097 UK Biobank study participants. Using 2,571 genome-wide significant associations, we demonstrate that the genetic determinants of testosterone levels are substantially different between sexes and that genetically higher testosterone is harmful for metabolic diseases in women but beneficial in men. For example, a genetically determined 1 s.d. higher testosterone increases the risks of type 2 diabetes (odds ratio (OR) = 1.37 (95% confidence interval (95% CI): 1.22-1.53)) and polycystic ovary syndrome (OR = 1.51 (95% CI: 1.33-1.72)) in women, but reduces type 2 diabetes risk in men (OR = 0.86 (95% CI: 0.76-0.98)). We also show adverse effects of higher testosterone on breast and endometrial cancers in women and prostate cancer in men. Our findings provide insights into the disease impacts of testosterone and highlight the importance of sex-specific genetic analyses.

Unraveling the functional role of the orphan solute carrier, SLC22A24 in the transport of steroid conjugates through metabolomic and genome-wide association studies

Variation in steroid hormone levels has wide implications for health and disease. The genes encoding the proteins involved in steroid disposition represent key determinants of interindividual variation in steroid levels and ultimately, their effects. Beginning with metabolomic data from genome-wide association studies (GWAS), we observed that genetic variants in the orphan transporter, SLC22A24 were significantly associated with levels of androsterone glucuronide and etiocholanolone glucuronide (sentinel SNPs p-value <1x10-30). In cells over-expressing human or various mammalian orthologs of SLC22A24, we showed that steroid conjugates and bile acids were substrates of the transporter. Phylogenetic, genomic, and transcriptomic analyses suggested that SLC22A24 has a specialized role in the kidney and appears to function in the reabsorption of organic anions, and in particular, anionic steroids. Phenome-wide analysis showed that functional variants of SLC22A24 are associated with human disease such as cardiovascular diseases and acne, which have been linked to dysregulated steroid metabolism. Collectively, these functional genomic studies reveal a previously uncharacterized protein involved in steroid homeostasis, opening up new possibilities for SLC22A24 as a pharmacological target for regulating steroid levels.