A Multi-SNP Locus-Association Method Reveals a Substantial Fraction of the Missing Heritability.

There are many known examples of multiple semi-independent associations at individual loci; such associations might arise either because of true allelic heterogeneity or because of imperfect tagging of an unobserved causal variant. This phenomenon is of great importance in monogenic traits but has not yet been systematically investigated and quantified in complex-trait genome-wide association studies (GWASs). Here, we describe a multi-SNP association method that estimates the effect of loci harboring multiple association signals by using GWAS summary statistics. Applying the method to a large anthropometric GWAS meta-analysis (from the Genetic Investigation of Anthropometric Traits consortium study), we show that for height, body mass index (BMI), and waist-to-hip ratio (WHR), 3%, 2%, and 1%, respectively, of additional phenotypic variance can be explained on top of the previously reported 10% (height), 1.5% (BMI), and 1% (WHR). The method also permitted a substantial increase (by up to 50%) in the number of loci that replicate in a discovery-validation design. Specifically, we identified 74 loci at which the multi-SNP, a linear combination of SNPs, explains significantly more variance than does the best individual SNP. A detailed analysis of multi-SNPs shows that most of the additional variability explained is derived from SNPs that are not in linkage disequilibrium with the lead SNP, suggesting a major contribution of allelic heterogeneity to the missing heritability.

Association between bipolar disorder and monoamine oxidase A gene polymorphisms: results of a multicenter study

OBJECTIVE: Although genetic factors have been implicated in the etiology of bipolar disorder, no specific gene has been conclusively identified. Given the link between abnormalities in serotonergic neurotransmission and bipolar disorder, a candidate gene association approach was applied to study the involvement of the monoamine oxidase A (MAOA) gene, which codes for a catabolic enzyme of serotonin, in the susceptibility to bipolar disorder. METHOD: In France and Switzerland, 272 patients with bipolar disorder and 122 healthy subjects were typed for three polymorphic markers of the MAOA gene: the MAOA-CA repeat, the MAOA restriction fragment length polymorphism (RFLP), and a repeat directly adjacent to the variable number of tandem repeats (VNTR) locus. RESULTS: A significant difference in the distribution of the alleles for the MAOA-CA repeat was observed between the female bipolar patients and comparison group. CONCLUSIONS: The results obtained in the French and Swiss population confirm findings from two studies conducted in the United Kingdom.

Association of work related chronic stressors and psychiatric symptoms in a Swiss sample of police officers : a cross sectional questionnaire study

Purpose (1) To identify work related stressors that are associated with psychiatric symptoms in a Swiss sample of policemen and (2) to develop a model for identifying officers at risk for developing mental health problems. Method The study design is cross sectional. A total of 354 male police officers answered a questionnaire assessing a wide spectrum of work related stressors. Psychiatric symptoms were assessed using the "TST questionnaire" (Langner in J Health Hum Behav 4, 269-276, 1962). Logistic regression with backward procedure was used to identify a set of variables collectively associated with high scores for psychiatric symptoms. Results A total of 42 (11.9%) officers had a high score for psychiatric symptoms. Nearly all potential stressors considered were significantly associated (at P < 0.05) with a high score for psychiatric symptoms. A significant model including 6 independent variables was identified: lack of support from superior and organization OR = 3.58 (1.58-8.13), self perception of bad quality work OR = 2.99 (1.35-6.59), inadequate work schedule OR = 2.84 (1.22-6.62), high mental/intellectual demand OR = 2.56 (1.12-5.86), age (in decades) OR = 1.82 (1.21-2.73), and score for physical environment complaints OR = 1.30 (1.03-1.64). Conclusions Most of work stressors considered are associated with psychiatric symptoms. Prevention should target the most frequent stressors with high association to symptoms. Complaints of police officers about stressors should receive proper consideration by the management of public administration. Such complaints might be the expression of psychiatric caseness requiring medical assistance. Particular attention should be given to police officers complaining about many stressors identified in this study's multiple model. [Authors]

Absence of association between specific common variants of the obesity-related FTO gene and psychological and behavioral eating disorder phenotypes.

Extensive population-based genome-wide association studies have identified an association between the FTO gene and BMI; however, the mechanism of action is still unknown. To determine whether FTO may influence weight regulation through psychological and behavioral factors, seven single-nucleotide polymorphisms (SNPs) of the FTO gene were genotyped in 1,085 individuals with anorexia nervosa (AN) and 677 healthy weight controls from the international Price Foundation Genetic Studies of Eating Disorders. Each SNP was tested in association with eating disorder phenotypes and measures that have previously been associated with eating behavior pathology: trait anxiety, harm-avoidance, novelty seeking, impulsivity, obsessionality, compulsivity, and concern over mistakes. After appropriate correction for multiple comparisons, no significant associations between individual FTO gene SNPs and eating disorder phenotypes or related eating behavior pathology were identified in cases or controls. Thus, this study found no evidence that FTO gene variants associated with weight regulation in the general population are associated with eating disorder phenotypes in AN participants or matched controls. © 2011 Wiley-Liss, Inc.

Association of moderate alcohol use and binge drinking during pregnancy with neonatal health.

Background:  Heavy drinking and smoking during pregnancy are known to have a negative impact on the unborn child. However, the impact of low-to-moderate alcohol consumption and binge drinking has been debated recently. The aim of this study was to examine the relationship of moderate prenatal drinking and binge drinking with birthweight, being small for gestational age (SGA) at birth, preterm birth, and neonatal asphyxia. Methods:  Moderate alcohol drinking, binge drinking, and several possible confounders were assessed in 1,258 pregnant women; information on neonatal health was obtained at birth. Results:  Results indicate that 30.8% of the women drank at low levels (<2 glasses/wk), 7.9% drank moderately (2 to 4 glasses/wk), and 0.9% showed higher levels of drinking (≥5 glasses/wk); 4.7% reported binge drinking (defined as ≥3 glasses/occasion). 6.4% of the children were SGA (<10th percentile of birthweight adjusted for gestational age), 4.6% were preterm (<37th week of gestation), and 13.0% showed asphyxia (arterial cord pH <7.10 and/or arterial cord lactate >6.35 mmol and/or Apgar score <7 at 5 minutes). When controlling for maternal age, citizenship, occupational status, parity, smoking, use of prescription/over-the-counter drugs, illicit drug use, and child gender moderate drinking was related to lower birthweight (p < 0.01), and moderate drinking and binge drinking were associated with neonatal asphyxia at trend level (p = 0.06 and p = 0.09). Moderate drinking and binge drinking were not related to length of gestation. Conclusions:  In contrast to recent reviews in the field, our results assume that moderate drinking and binge drinking are risk factors for neonatal health.

Five years of denosumab exposure in women with postmenopausal osteoporosis: results from the first two years of the FREEDOM extension.

The 3-year FREEDOM trial assessed the efficacy and safety of 60 mg denosumab every 6 months for the treatment of postmenopausal women with osteoporosis. Participants who completed the FREEDOM trial were eligible to enter an extension to continue the evaluation of denosumab efficacy and safety for up to 10 years. For the extension results presented here, women from the FREEDOM denosumab group had 2 more years of denosumab treatment (long-term group) and those from the FREEDOM placebo group had 2 years of denosumab exposure (cross-over group). We report results for bone turnover markers (BTMs), bone mineral density (BMD), fracture rates, and safety. A total of 4550 women enrolled in the extension (2343 long-term; 2207 cross-over). Reductions in BTMs were maintained (long-term group) or occurred rapidly (cross-over group) following denosumab administration. In the long-term group, lumbar spine and total hip BMD increased further, resulting in 5-year gains of 13.7% and 7.0%, respectively. In the cross-over group, BMD increased at the lumbar spine (7.7%) and total hip (4.0%) during the 2-year denosumab treatment. Yearly fracture incidences for both groups were below rates observed in the FREEDOM placebo group and below rates projected for a "virtual untreated twin" cohort. Adverse events did not increase with long-term denosumab administration. Two adverse events in the cross-over group were adjudicated as consistent with osteonecrosis of the jaw. Five-year denosumab treatment of women with postmenopausal osteoporosis maintained BTM reduction and increased BMD, and was associated with low fracture rates and a favorable risk/benefit profile.

Association of sports club participation with fitness and fatness in children.

Decreased fitness and increased fatness are relevant factors for decreased cardiovascular and bone health in children. One way to increase physical activity and hence fitness and to reduce the risk for overweight might be sports club participation (SCP). PURPOSE: To investigate the association of SCP with fatness and fitness in children in general and in those with increased risk for overweight and/or low fitness. METHODS: A cross-sectional study was conducted in a random sample of 502 first- and fifth-grade primary school children. Fitness components were determined by 10 motor tests and body fatness by the sum of four skinfolds. SCP was defined as participation of at least once a week. RESULTS: Two thirds of all children were participating in a sports club. Girls' and boys' participation rate as well as those of overweight children and of children with overweight parents were comparable to their respective normal weight peers. In contrast, children from migrant families (odds ratio = 0.31; 95% confidence interval = 0.20-0.48) and from inactive parents (odds ratio = 0.16; 95% confidence interval = 0.05-0.45) participated significantly less (all P < 0.001). SCP was associated with endurance (0.53 > beta > 0.37, all P < 0.05) and partly with speed, strength, and coordination (0.41 > beta > 0.18, all P < 0.05). In overweight children and in children from overweight parents and migrant families, this association was not found. There was no association between SCP and fatness in any of the groups. CONCLUSIONS: SCP rates were high and were associated with higher levels of most fitness components in children. Participation rates were lower for children of migrant families and children from inactive parents. In addition, the association between SCP and fitness components was not found in overweight children and in children from overweight parents and migrant families.

Familial occurrence of an association of multiple intestinal atresia and choanal atresia: a new syndrome?

We report on two familial cases from a non-consanguineous marriage, presenting multiple intestinal and choanal atresia. Massive hydramnios and dilatation of the bowel were observed at 29 weeks of gestation during routine ultrasound scan of a healthy mother. The fetal karyotype was normal and cystic fibrosis screening was negative. Regular scans were performed throughout the pregnancy. The child was born at 34 weeks gestation. Choanal atresia was diagnosed at birth and abdominal investigations showed multiple atresia interesting both the small bowel and the colon. Further interventions were necessary because of recurrent obstructions. During the following pregnancy, a dilatation of the fetal intestinal tract was detected by ultrasonography at 27 weeks of gestation. Pregnancy was interrupted. Post-mortem examination of the fetus confirmed the stenosis of long segments of the small intestine associated with areas of colonic atresia. In both cases, histology and distribution were consistent with those reported in hereditary multiple intestinal atresia (HMIA). An association between multiple intestinal and choanal atresia has never been reported. We suggest it could correspond to a new autosomal recessive entity for which cytogenetic investigations and high-resolution array CGH revealed no visible anomalies.

Association between Inflammatory and Obesity Markers in a Swiss Population-Based Sample (CoLaus Study).

Objective: To assess the associations between obesity markers (BMI, waist circumference and %body fat) and inflammatory markers (interleukin-1β (IL-1β); interleukin-6 (IL-6); tumor necrosis factor-α (TNF-α) and high-sensitivity C-reactive protein (hs-CRP)). Methods: Population sample of 2,884 men and 3,201 women aged 35-75 years. Associations were assessed using ridge regression adjusting for age, leisure-time physical activity, and smoking. Results: No differences were found in IL-1β levels between participants with increased obesity markers and healthy counterparts; multivariate regression showed %body fat to be negatively associated with IL-1β. Participants with high %body fat or abdominal obesity had higher IL-6 levels, but no independent association between IL-6 levels and obesity markers was found on multivariate regression. Participants with abdominal obesity had higher TNF-α levels, and positive associations were found between TNF-α levels and waist circumference in men and between TNF-α levels and BMI in women. Obese participants had higher hs-CRP levels, and these differences persisted after multivariate adjustment; similarly, positive associations were found between hs-CRP levels and all obesity markers studied. Conclusion: Obesity markers are differentially associated with cytokine levels. %Body fat is negatively associated with IL-1β; BMI (in women) and waist circumference (in men) are associated with TNF-α; all obesity markers are positively associated with hs-CRP. Copyright © 2012 S. Karger GmbH, Freiburg.

Genome-wide association study identifies six new loci influencing pulse pressure and mean arterial pressure.

Numerous genetic loci have been associated with systolic blood pressure (SBP) and diastolic blood pressure (DBP) in Europeans. We now report genome-wide association studies of pulse pressure (PP) and mean arterial pressure (MAP). In discovery (N = 74,064) and follow-up studies (N = 48,607), we identified at genome-wide significance (P = 2.7 × 10(-8) to P = 2.3 × 10(-13)) four new PP loci (at 4q12 near CHIC2, 7q22.3 near PIK3CG, 8q24.12 in NOV and 11q24.3 near ADAMTS8), two new MAP loci (3p21.31 in MAP4 and 10q25.3 near ADRB1) and one locus associated with both of these traits (2q24.3 near FIGN) that has also recently been associated with SBP in east Asians. For three of the new PP loci, the estimated effect for SBP was opposite of that for DBP, in contrast to the majority of common SBP- and DBP-associated variants, which show concordant effects on both traits. These findings suggest new genetic pathways underlying blood pressure variation, some of which may differentially influence SBP and DBP.

Genome-wide association study of virologic response with efavirenz-containing or abacavir-containing regimens in AIDS clinical trials group protocols.

BACKGROUND: Efavirenz and abacavir are components of recommended first-line regimens for HIV-1 infection. We used genome-wide genotyping and clinical data to explore genetic associations with virologic failure among patients randomized to efavirenz-containing or abacavir-containing regimens in AIDS Clinical Trials Group (ACTG) protocols. PARTICIPANTS AND METHODS: Virologic response and genome-wide genotype data were available from treatment-naive patients randomized to efavirenz-containing (n=1596) or abacavir-containing (n=786) regimens in ACTG protocols 384, A5142, A5095, and A5202. RESULTS: Meta-analysis of association results across race/ethnic groups showed no genome-wide significant associations (P<5×10) with virologic response for either efavirenz or abacavir. Our sample size provided 80% power to detect a genotype relative risk of 1.8 for efavirenz and 2.4 for abacavir. Analyses focused on CYP2B genotypes that define the lowest plasma efavirenz exposure stratum did not show associations nor did analysis limited to gene sets predicted to be relevant to efavirenz and abacavir disposition. CONCLUSION: No single polymorphism is associated strongly with virologic failure with efavirenz-containing or abacavir-containing regimens. Analyses to better consider context, and that minimize confounding by nongenetic factors, may show associations not apparent here.