Frequent oil baths and skin barrier during infancy in the PreventADALL study.

BACKGROUND: In the general population randomized controlled trial PreventADALL, frequent emollient bath additives from 2 weeks of age did not prevent atopic dermatitis, while the effect on skin barrier function throughout infancy is not established. OBJECTIVES: The primary aim of this exploratory substudy was to assess the effect of mineral-based oil baths on transepidermal water loss (TEWL) and dry skin through infancy, and secondarily to explore if filaggrin (FLG) mutations modified the effect. METHODS: Overall, 2153 infants were included and randomized to either the 'Skin intervention' (SI) group (n = 995) (oil bath 4 times weekly from 2 weeks through 8 months) or 'No skin intervention' (NSI) group (n = 1158), with TEWL measurements at 3, 6 and/or 12 months of age. Information on FLG mutation status was available for 1683 of these infants. Effects of the skin intervention on TEWL and dry skin through infancy were assessed by mixed-effects regression modelling. Background characteristics and protocol adherence were collected from electronic questionnaires, birth records and weekly diaries. RESULTS: The TEWL (95% confidence interval) was on average 0.42 g m-2 h-1 (0.13-0.70, P = 0.004) higher in the SI group compared with the NSI group through the first year of life, with significantly higher levels at 3 months [8.6 (8.3-9.0) vs. 7.6 (7.3-7.9)], but similar at 6 and 12 months. Dry skin was observed significantly more often in the NSI group compared with the SI group at 3 months (59% vs. 51%) and at 6 months of age (63% vs. 53%), while at 12 months of age, the difference was no longer significant. At 3 months, the TEWL of FLG mutation carriers was similar to the TEWL in the SI group. No interaction between SI and FLG mutation was found in the first year of life. CONCLUSIONS: Infants given frequent oil baths from 2 weeks of age had reduced skin barrier function through infancy compared with controls, largely attributed to higher TEWL at 3 months of age, while the skin at 3 and 6 months appeared less dry in infants subjected to the skin intervention.

Atopic dermatitis (AD) affects approximately 20% of children in industrialized countries. AD causes dry, itchy skin and can increase the chance of infections. This study was a substudy of the large Scandinavian PreventADALL trial, including 2394 infants, recruited from the general population between 2014 and 2016. Children in this trial were allocated randomly to receive either a skin intervention, food intervention, combined intervention, or no intervention. Children were examined at 3, 6 and 12 months of age. The examinations involved an investigation of the skin, to evaluate dry skin and skin barrier function by transepidermal water loss (TEWL) in the outer layers of the skin (higher TEWL suggests decreased skin barrier function). The skin intervention consisted of oil baths at least 4 times per week from 2 weeks of age through 8 months of age, and have previously not been shown to prevent AD by 1 and 3 years of age. We aimed to investigate whether frequent oil baths had any effect on TEWL and dry skin. We found that the skin intervention increased TEWL in the first year of life, especially at 3 months of age. Dry skin was less common in the skin intervention groups compared with the groups with no skin intervention. Infants with mutations in the gene coding for a skin barrier protein, called filaggrin, were associated with increased TEWL; however, in the skin intervention group, TEWL was similar among the infants with or without filaggrin mutations. Our findings suggest that oil baths several times per week from early infancy transiently decreases skin barrier function.

Atypical Neuropsychiatric Presentation of FTD-ALS Caused by a Pathogenic Repeat Expansion in C9orf72: A Case Report.

The case report describes the presentation of a 42-year-old male ultimately diagnosed with FTD-ALS caused by a genetic mutation, who initially presented with atypical psychiatric symptoms. Given that the initial clinical manifestations of FTD-ALS can be quite variable, the diagnosis is often challenging; the case report aims to highlight several key considerations in the diagnostic assessment, including genetic testing in order to guide clinicians in more timely diagnosis and ultimately improve patient care.

A case report of an atypical severe case of skin picking disorder managed by a multidisciplinary team.

BACKGROUND: While skin picking disorder remains relatively common, it often does not present to psychiatry until significant morbidity or comorbidities are reached. It is described as recurrent picking of skin leading to skin lesions, with repeated attempts to decrease or stop skin picking. It is also often associated with significant distress or functional impairment. There has been limited research in this specific disorder and treatment efficacy has often been poor in severe cases. For various reasons, only a small amount of patients with this disorder present to care, and often to a multidisciplinary team prior to psychiatry. CASE PRESENTATION: This is a case presentation of a 44 year old male with a complex past psychiatric history, ultimately untreated for an underlying skin picking disorder. He presented for urgent medical care following a self-inflicted wound through the central frontal bone and dura over the course of 2 years. He was treated with current psychiatric evidence based medicine, including an SSRI, antipsychotic augmentation and NAC, along with habit reversal techniques during the admission. He was concurrently managed with the neurosurgery team, initially with a poor prognosis due to the severity of his presentation. He required debriding of the devitalized bone within the adjacent brain to cover the dural defect, IV antibiotics for 6 weeks, and an initial skin graft on his initial admission. CONCLUSIONS: This case in particular highlighted the importance of urgent treatment via a multidisciplinary approach to avoid mortality. It highlights the importance of increasing awareness about the disorder and that treatment with SSRI's, along with antipsychotic and NAC adjuncts remains the mainstay of acute treatment.

Early food intervention and skin emollients to prevent food allergy in young children (PreventADALL): a factorial, multicentre, cluster-randomised trial.

BACKGROUND: Primary prevention of food allergy by early introduction of allergenic foods seems promising. We aimed to determine whether early food introduction or the application of regular skin emollients in infants from a general population reduced the risk of food allergy. METHODS: This 2 × 2 factorial, cluster-randomised trial was done at Oslo University Hospital and Østfold Hospital Trust, Oslo, Norway, and Karolinska University Hospital, Stockholm, Sweden. Infants of women recruited antenatally at the routine 18-week ultrasound examination were cluster-randomised at birth to the following groups: (1) no intervention group; (2) the skin intervention group (skin emollients; bath additives and facial cream; from age 2 weeks to <9 months, both at least four times per week); (3) the food intervention group (early complementary feeding of peanut, cow's milk, wheat, and egg from age 3 months); or (4) combined intervention group (skin and food interventions). Participants were randomly assigned (1:1:1:1) using computer-generated randomisation based on clusters of 92 geographical areas and eight 3-month time blocks. Study personnel performing clinical assessments were masked to group allocation. The primary outcome was allergy to any interventional food at 36 months of age. The primary efficacy analysis was done by intention-to-treat analysis, which included all participants who were randomly assigned, apart from three individuals who withdrew their consent. This was a study performed within ORAACLE (the Oslo Research Group of Asthma and Allergy in Childhood; the Lung and Environment). This study is registered as ClinicalTrials.gov, NCT02449850. FINDINGS: We recruited 2697 women with 2701 pregnancies, from whom 2397 newborn infants were enrolled between April 14, 2015, and April 11, 2017. Of these infants, 597 were randomly assigned to the no intervention group, 575 to the skin intervention group, 642 to the food intervention group, and 583 to the combined intervention group. One participant in each of the no intervention, food intervention, and skin intervention groups withdrew consent and were therefore not included in any analyses. Food allergy was diagnosed in 44 children; 14 (2·3%) of 596 infants in the non-intervention group, 17 (3·0%) of 574 infants in the skin intervention group, six (0·9%) of 641 infants in the food intervention group, and seven (1·2%) of 583 infants in the combined intervention group. Peanut allergy was diagnosed in 32 children, egg allergy in 12 children, and milk allergy in four children. None had allergy to wheat. Prevalence of food allergy was reduced in the food intervention group compared with the no food intervention group (risk difference -1·6% [95% CI -2·7 to -0·5]; odds ratio [OR] 0·4 [95% CI 0·2 to 0·8]), but not compared with the skin intervention group (0·4% [95% CI -0·6 to 1· 5%]; OR 1·3 [0·7 to 2·3]), with no significant interaction effect (p=1·0). Preventing food allergy in one child required early exposure to allergenic foods in 63 children. No serious adverse events were observed. INTERPRETATION: Exposure to allergenic foods from 3 months of age reduced food allergy at 36 months in a general population. Our results support that early introduction of common allergenic foods is a safe and effective strategy to prevent food allergy. FUNDING: Full funding sources listed at end of paper (see Acknowledgments).

Feeding Practices and Dietary Diversity in the First Year of Life: PreventADALL, a Scandinavian Randomized Controlled Trial and Birth Cohort Study.

BACKGROUND: Breastmik is considered the optimal source of nutrition in early infancy. However, recommendations and practices for when and how complementary food should be introduced in the first year of life vary worldwide. Early introduction of allergenic foods may prevent food allergies, but if early food introduction influences infant feeding practices is less known. OBJECTIVES: We sought to assess infant feeding practices in the first year of life and to determine if early interventional food introduction influences breastfeeding and dietary diversity. METHODS: Dietary intake was assessed in infants from the population-based clinical trial Preventing Atopic Dermatitis and ALLergies (PreventADALL) in children study. A total of 2397 infants were cluster-randomized at birth into 4 different groups: 1) control, 2) skin intervention, 3) introduction to 4 allergenic foods between 3 and 4 mo of age: peanut, cow milk, wheat, and egg, as small tastings until 6 mo, and 4) combined skin and food interventions. Dietary data were available from at least one of the 3-, 6-, 9-, and 12-mo questionnaires in 2059 infants. In the present analysis, groups 1 and 2 constitute the No Food Intervention group, whereas groups 3 and 4 constitute the Food Intervention group. We used the log-rank test and Cox regression to assess the impact of food intervention on age of breastfeeding cessation. Mixed effects logistic regression was used to compare dietary diversity, defined as the number of food categories consumed, between intervention groups. RESULTS: At 3, 6, 9, and 12 mo, 95%, 88%, 67%, and 51% were breastfed, respectively, and breastfeeding duration was not affected by the food intervention. In the No Food Intervention group, mean age of complementary food introduction was 18.3 wk (confidence interval [CI]: 18.1, 18.5). In the Food Intervention group, the dietary diversity score was 1.39 units (CI: 1.16, 1.62) higher at 9 mo (P < 0.001) and 0.7 units (CI: 0.5, 0.9) higher at 12 mo (P < 0.001) compared to the No Food Intervention group. CONCLUSIONS: Early food intervention did not affect breastfeeding rates and increased dietary diversity at 9 and 12 mo.

Evaluation of Skin Prick Test Reading Time at 10 versus 15 min in Young Infants.

INTRODUCTION: The optimal time point for reading the mean wheal diameter (MWD) of a skin prick test (SPT) in infants is not established. We aimed to assess if either of two reading time points of the SPT, 10 or 15 min, was superior to detect allergic sensitization (AS) in 6-month-old infants. METHODS: In 1,431 6-month-old infants from the population-based Preventing Atopic Dermatitis and ALLergies in children (PreventADALL) mother-child cohort, the SPT was performed with standard solutions for egg, cow's milk, peanut, wheat, soy, birch, timothy, dog, and cat. The MWD was measured after 10 and 15 min. AS was defined as a positive SPT with MWD ≥2 mm larger than the negative control. RESULTS: Overall, 149 (10.4%) infants were sensitized to at least one allergen at 10 and/or 15 min, while 138 (9.6%) had a positive SPT at 10 min and 141 (9.9%) at 15 min. A total of 12,873 allergen pricks were performed with 212 (1.6%) being positive at any time point, 194 (1.5%) positive at 10 min, and 196 (1.5%) positive at 15 min. The mean (95% CI) histamine MWD of 3.8 (3.8, 3.9) mm at 10 min was significantly larger than the 3.6 (3.6, 3.7) mm at 15 min. DISCUSSION/CONCLUSIONS: Reading the SPT after both 10 and 15 min increased the number of 6-month-old infants with documented AS compared to reading after one time point only. As neither 10 nor 15 min reading time was superior to the other in detecting AS, our results indicate that readings at both time points should be considered. However, the histamine MWD was significantly larger at 10 min compared to 15 min. Reappraisal of SPT reading in infancy may be warranted.

Adherence to a healthy and potentially sustainable Nordic diet is associated with child development in The Norwegian Mother, Father and Child Cohort Study (MoBa).

BACKGROUND: The rapid neurodevelopment that occurs during the first years of life hinges on adequate nutrition throughout fetal life and early childhood. Therefore, adhering to a dietary pattern based on healthy foods during pregnancy and the first years of life may be beneficial for future development. The aim of this paper was to investigate the relationship between adherence to a healthy and potentially sustainable Nordic diet during pregnancy and in early childhood and child development. METHODS: This study is based on the Norwegian Mother, Father and Child Cohort Study (MoBa) and uses data from the Medical Birth Registry of Norway (MBRN). In 83,800 mother-child pairs, maternal pregnancy diet and child diet at 6 months, 18 months and 3 years were scored according to adherence to the New Nordic Diet (NND). NND scores were calculated both as a total score and categorized into low, medium, or high adherence. Child communication and motor development skills were reported by parents at 6 months, 18 months, 3 and 5 years, using short forms of the Ages and Stages Questionnaire and the Child Development Inventory. Associations of NND adherence with child development were estimated with linear and logistic regression in crude and adjusted models. RESULTS: When examining the NND and child developmental scores as percentages of the total scores, we found positive associations between the NND scores (both maternal pregnancy diet and child diet) and higher scoring on child development (adjusted [Formula: see text] s [95% confidence intervals] ranging from 0.007 [0.004, 0.009] to 0.045 [0.040, 0.050]). We further found that low and medium adherence to NND were associated with higher odds of later emerging developmental skills compared to high NND adherence at nearly all measured timepoints (odds ratios [95% CI] ranging from significant values 1.15 [1.03-1.29] to 1.79 [1.55, 2.06] in adjusted analyses). CONCLUSIONS: Our findings support that adherence to a healthy and potentially sustainable diet early in life is important for child development every step of the way from pregnancy until age 5 years.

Letter to the editor regarding "Covid-19 transmission in fitness centers in Norway - a randomized trial".

In a recently published paper in BMC Public Health we read about a randomized trial on Covid-19 transmission performed in five fitness centers in Oslo, Norway, during the spring of 2020. In our opinion, this study has major shortcomings in design and methodology, which have not been addressed by the authors.

Fetal Thoracic Circumference and Lung Volume and Their Relation to Fetal Size and Pulmonary Artery Blood Flow.

OBJECTIVE: Research on early origins of lung disease suggests the need for studying the relationships of thoracic and lung size with fetal size and pulmonary circulation. The primary aim of this study is therefore to explore the associations between fetal thoracic circumference, lung volume, and fetal size. We also aim to assess if lung volume and thoracic circumference are associated with fetal pulmonary artery blood flow velocity measures. METHODS: Cross-sectional assessment of singleton pregnancies from the general population (n = 447) at 30 gestational weeks (GW) was performed using ultrasound measurement of fetal thoracic circumference, lung volume, head and abdominal circumference, and femur length. We obtained Doppler blood flow velocity measures from the proximal branches of the fetal pulmonary artery. Associations between variables were studied using Pearson's correlation and multiple linear regression analyses. RESULTS: Both thoracic circumference and lung volume correlated with fetal size measures, ranging from r = 0.64 between thoracic circumference and abdominal circumference, to r = 0.28 between lung volume and femur length. Adjustment for gestational age, maternal nicotine use, pre-pregnancy body mass index, and fetal sex marginally influenced the associations with abdominal circumference. The correlations of thoracic circumference and lung volume with pulmonary artery blood flow velocity measures were weak (r ≤ 0.17). CONCLUSION: We found moderate to low correlation between thoracic circumference, lung volume, and fetal size at 30 GW. The closest relationship was with the abdominal circumference. We found low correlations of thoracic circumference and lung volume with pulmonary artery blood flow velocity measures.

Skin emollient and early complementary feeding to prevent infant atopic dermatitis (PreventADALL): a factorial, multicentre, cluster-randomised trial.

BACKGROUND: Skin emollients applied during early infancy could prevent atopic dermatitis, and early complementary food introduction might reduce food allergy in high-risk infants. The study aimed to determine if either regular skin emollients applied from 2 weeks of age, or early complementary feeding introduced between 12 and 16 weeks of age, reduced development of atopic dermatitis by age 12 months in the general infant population. METHODS: This population-based 2×2 factorial, randomised clinical trial was done at Oslo University Hospital and Østfold Hospital Trust, Oslo, Norway; and Karolinska University Hospital, Stockholm, Sweden. Infants of women recruited antenatally at the routine ultrasound pregnancy screening at 18 weeks were cluster-randomised at birth from 2015 to 2017 to the following groups: (1) controls with no specific advice on skin care while advised to follow national guidelines on infant nutrition (no intervention group); (2) skin emollients (bath additives and facial cream; skin intervention group); (3) early complementary feeding of peanut, cow's milk, wheat, and egg (food intervention group); or (4) combined skin and food interventions (combined intervention group). Participants were randomly assigned (1:1:1:1) using computer- generated cluster randomisation based on 92 geographical living area blocks as well as eight 3-month time blocks. Carers were instructed to apply the interventions on at least 4 days per week. Atopic dermatitis by age 12 months was the primary outcome, based on clinical investigations at 3, 6 and 12 months by investigators masked to group allocation. Atopic dermatitis was assessed after completing the 12-month investigations and diagnosed if either of the UK Working Party and Hanifin and Rajka (12 months only) diagnostic criteria were fulfilled. The primary efficacy analyses was done by intention-to-treat analysis on all randomly assigned participants. Food allergy results will be reported once all investigations at age 3 years are completed in 2020. This was a study performed within ORAACLE (the Oslo Research Group of Asthma and Allergy in Childhood; the Lung and Environment). The study is registered at clinicaltrials.gov, NCT02449850. FINDINGS: 2697 women were recruited between Dec 9, 2014, and Oct 31, 2016, from whom 2397 newborn infants were enrolled from April 14, 2015, to April 11, 2017. Atopic dermatitis was observed in 48 (8%) of 596 infants in the no intervention group, 64 (11%) of 575 in the skin intervention group, 58 (9%) of 642 in the food intervention group, and 31 (5%) of 583 in the combined intervention group. Neither skin emollients nor early complementary feeding reduced development of atopic dermatitis, with a risk difference of 3·1% (95% CI -0·3 to 6·5) for skin intervention and 1·0% (-2·1 to 4·1) for food intervention, in favour of control. No safety concerns with the interventions were identified. Reported skin symptoms and signs (including itching, oedema, exanthema, dry skin, and urticaria) were no more frequent in the skin, food, and combined intervention groups than in the no intervention group. INTERPRETATION: Neither early skin emollients nor early complementary feeding reduced development of atopic dermatitis by age 12 months. Our study does not support the use of these interventions to prevent atopic dermatitis by 12 months of age in infants. FUNDING: The study was funded by several public and private funding bodies: The Regional Health Board South East, The Norwegian Research Council, Health and Rehabilitation Norway, The Foundation for Healthcare and Allergy Research in Sweden-Vårdalstiftelsen, Swedish Asthma and Allergy Association's Research Foundation, Swedish Research Council-the Initiative for Clinical Therapy Research, The Swedish Heart-Lung Foundation, SFO-V at the Karolinska Institute, Freemason Child House Foundation in Stockholm, Swedish Research Council for Health, Working Life and Welfare-FORTE, Oslo University Hospital, the University of Oslo, and Østfold Hospital Trust.

Functional annotation of chemical libraries across diverse biological processes.

Chemical-genetic approaches offer the potential for unbiased functional annotation of chemical libraries. Mutations can alter the response of cells in the presence of a compound, revealing chemical-genetic interactions that can elucidate a compound's mode of action. We developed a highly parallel, unbiased yeast chemical-genetic screening system involving three key components. First, in a drug-sensitive genetic background, we constructed an optimized diagnostic mutant collection that is predictive for all major yeast biological processes. Second, we implemented a multiplexed (768-plex) barcode-sequencing protocol, enabling the assembly of thousands of chemical-genetic profiles. Finally, based on comparison of the chemical-genetic profiles with a compendium of genome-wide genetic interaction profiles, we predicted compound functionality. Applying this high-throughput approach, we screened seven different compound libraries and annotated their functional diversity. We further validated biological process predictions, prioritized a diverse set of compounds, and identified compounds that appear to have dual modes of action.

Errata: Functional annotation of chemical libraries across diverse biological processes.

This corrects the article DOI: 10.1038/nchembio.2436.

Errata: Functional annotation of chemical libraries across diverse biological processes.

This corrects the article DOI: 10.1038/nchembio.2436.

Prenatal maternal depressive symptoms and infant DNA methylation: a longitudinal epigenome-wide study.

Background: Prenatal maternal stress increases the risk of offspring developmental and psychological difficulties. The biological mechanisms behind these associations are mostly unknown. One explanation suggests that exposure of the fetus to maternal stress may influence DNA methylation. However, this hypothesis is largely based on animal studies, and human studies of candidate genes from single timepoints. Aim: The aim of this study was to investigate if prenatal maternal stress, in the form of maternal depressive symptoms, was associated with variation in genome-wide DNA methylation at two timepoints. Methods: One-hundred and eighty-four mother-child dyads were selected from a population of pregnant women in the Little-in-Norway study. The Edinburgh Postnatal Depression Scale (EPDS) measured maternal depressive symptoms. It was completed by the pregnant mothers between weeks 17 and 32 of gestation. DNA was obtained from infant saliva cells at two timepoints (age 6 weeks and 12 months). DNA methylation was measured in 274 samples from 6 weeks (n = 146) and 12 months (n = 128) using the Illumina Infinium HumanMethylation 450 BeadChip. Linear regression analyses of prenatal maternal depressive symptoms and infant methylation were performed at 6 weeks and 12 months separately, and for both timepoints together using a mixed model. Results: The analyses revealed no significant genome-wide association between maternal depressive symptoms and infant DNA methylation in the separate analyses and for both timepoints together. Conclusions: This sample of pregnant women and their infants living in Norway did not reveal associations between maternal depressive symptoms and infant DNA methylation.

A correction for sample overlap in genome-wide association studies in a polygenic pleiotropy-informed framework.

BACKGROUND: There is considerable evidence that many complex traits have a partially shared genetic basis, termed pleiotropy. It is therefore useful to consider integrating genome-wide association study (GWAS) data across several traits, usually at the summary statistic level. A major practical challenge arises when these GWAS have overlapping subjects. This is particularly an issue when estimating pleiotropy using methods that condition the significance of one trait on the signficance of a second, such as the covariate-modulated false discovery rate (cmfdr). RESULTS: We propose a method for correcting for sample overlap at the summary statistic level. We quantify the expected amount of spurious correlation between the summary statistics from two GWAS due to sample overlap, and use this estimated correlation in a simple linear correction that adjusts the joint distribution of test statistics from the two GWAS. The correction is appropriate for GWAS with case-control or quantitative outcomes. Our simulations and data example show that without correcting for sample overlap, the cmfdr is not properly controlled, leading to an excessive number of false discoveries and an excessive false discovery proportion. Our correction for sample overlap is effective in that it restores proper control of the false discovery rate, at very little loss in power. CONCLUSIONS: With our proposed correction, it is possible to integrate GWAS summary statistics with overlapping samples in a statistical framework that is dependent on the joint distribution of the two GWAS.

Quality control for Illumina 450K methylation data in the absence of iDat files using correlation structure in pedigrees and repeated measures.

BACKGROUND: An important feature in many genomic studies is quality control and normalization. This is particularly important when analyzing epigenetic data, where the process of obtaining measurements can be bias prone. The GAW20 data was from the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN), a study with multigeneration families, where DNA cytosine-phosphate-guanine (CpG) methylation was measured pre- and posttreatment with fenofibrate. We performed quality control assessment of the GAW20 DNA methylation data, including normalization, assessment of batch effects and detection of sample swaps. RESULTS: We show that even after normalization, the GOLDN methylation data has systematic differences pre- and posttreatment. Through investigation of (a) CpGs sites containing a single nucleotide polymorphism, (b) the stability of breeding values for methylation across time points, and (c) autosomal gender-associated CpGs, 13 sample swaps were detected, 11 of which were posttreatment. CONCLUSIONS: This paper demonstrates several ways to perform quality control of methylation data in the absence of raw data files and highlights the importance of normalization and quality control of the GAW20 methylation data from the GOLDN study.

Epigenetics, heritability and longitudinal analysis.

BACKGROUND: Longitudinal data and repeated measurements in epigenome-wide association studies (EWAS) provide a rich resource for understanding epigenetics. We summarize 7 analytical approaches to the GAW20 data sets that addressed challenges and potential applications of phenotypic and epigenetic data. All contributions used the GAW20 real data set and employed either linear mixed effect (LME) models or marginal models through generalized estimating equations (GEE). These contributions were subdivided into 3 categories: (a) quality control (QC) methods for DNA methylation data; (b) heritability estimates pretreatment and posttreatment with fenofibrate; and (c) impact of drug response pretreatment and posttreatment with fenofibrate on DNA methylation and blood lipids. RESULTS: Two contributions addressed QC and identified large statistical differences with pretreatment and posttreatment DNA methylation, possibly a result of batch effects. Two contributions compared epigenome-wide heritability estimates pretreatment and posttreatment, with one employing a Bayesian LME and the other using a variance-component LME. Density curves comparing these studies indicated these heritability estimates were similar. Another contribution used a variance-component LME to depict the proportion of heritability resulting from a genetic and shared environment. By including environmental exposures as random effects, the authors found heritability estimates became more stable but not significantly different. Two contributions investigated treatment response. One estimated drug-associated methylation effects on triglyceride levels as the response, and identified 11 significant cytosine-phosphate-guanine (CpG) sites with or without adjusting for high-density lipoprotein. The second contribution performed weighted gene coexpression network analysis and identified 6 significant modules of at least 30 CpG sites, including 3 modules with topological differences pretreatment and posttreatment. CONCLUSIONS: Four conclusions from this GAW20 working group are: (a) QC measures are an important consideration for EWAS studies that are investigating multiple time points or repeated measurements; (b) application of heritability estimates between time points for individual CpG sites is a useful QC measure for DNA methylation studies; (c) drug intervention demonstrated strong epigenome-wide DNA methylation patterns across the 2 time points; and (d) new statistical methods are required to account for the environmental contributions of DNA methylation across time. These contributions demonstrate numerous opportunities exist for the analysis of longitudinal data in future epigenetic studies.

Identifying Novel Gene Variants in Coronary Artery Disease and Shared Genes With Several Cardiovascular Risk Factors.

RATIONALE: Coronary artery disease (CAD) is a critical determinant of morbidity and mortality. Previous studies have identified several cardiovascular disease risk factors, which may partly arise from a shared genetic basis with CAD, and thus be useful for discovery of CAD genes. OBJECTIVE: We aimed to improve discovery of CAD genes and inform the pathogenic relationship between CAD and several cardiovascular disease risk factors using a shared polygenic signal-informed statistical framework. METHODS AND RESULTS: Using genome-wide association studies summary statistics and shared polygenic pleiotropy-informed conditional and conjunctional false discovery rate methodology, we systematically investigated genetic overlap between CAD and 8 traits related to cardiovascular disease risk factors: low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, type 2 diabetes mellitus, C-reactive protein, body mass index, systolic blood pressure, and type 1 diabetes mellitus. We found significant enrichment of single-nucleotide polymorphisms associated with CAD as a function of their association with low-density lipoprotein, high-density lipoprotein, triglycerides, type 2 diabetes mellitus, C-reactive protein, body mass index, systolic blood pressure, and type 1 diabetes mellitus. Applying the conditional false discovery rate method to the enriched phenotypes, we identified 67 novel loci associated with CAD (overall conditional false discovery rate <0.01). Furthermore, we identified 53 loci with significant effects in both CAD and at least 1 of low-density lipoprotein, high-density lipoprotein, triglycerides, type 2 diabetes mellitus, C-reactive protein, systolic blood pressure, and type 1 diabetes mellitus. CONCLUSIONS: The observed polygenic overlap between CAD and cardiometabolic risk factors indicates a pathogenic relation that warrants further investigation. The new gene loci identified implicate novel genetic mechanisms related to CAD.

Germline mutations in MAP3K6 are associated with familial gastric cancer.

Gastric cancer is among the leading causes of cancer-related deaths worldwide. While heritable forms of gastric cancer are relatively rare, identifying the genes responsible for such cases can inform diagnosis and treatment for both hereditary and sporadic cases of gastric cancer. Mutations in the E-cadherin gene, CDH1, account for 40% of the most common form of familial gastric cancer (FGC), hereditary diffuse gastric cancer (HDGC). The genes responsible for the remaining forms of FGC are currently unknown. Here we examined a large family from Maritime Canada with FGC without CDH1 mutations, and identified a germline coding variant (p.P946L) in mitogen-activated protein kinase kinase kinase 6 (MAP3K6). Based on conservation, predicted pathogenicity and a known role of the gene in cancer predisposition, MAP3K6 was considered a strong candidate and was investigated further. Screening of an additional 115 unrelated individuals with non-CDH1 FGC identified the p.P946L MAP3K6 variant, as well as four additional coding variants in MAP3K6 (p.F849Sfs*142, p.P958T, p.D200Y and p.V207G). A somatic second-hit variant (p.H506Y) was present in DNA obtained from one of the tumor specimens, and evidence of DNA hypermethylation within the MAP3K6 gene was observed in DNA from the tumor of another affected individual. These findings, together with previous evidence from mouse models that MAP3K6 acts as a tumor suppressor, and studies showing the presence of somatic mutations in MAP3K6 in non-hereditary gastric cancers and gastric cancer cell lines, point towards MAP3K6 variants as a predisposing factor for FGC.