Comparison of Concordance of Peptic Ulcer Disease, Non-Adenomatous Intestinal Polyp, and Gallstone Disease in Korean Monozygotic and Dizygotic Twins: A Cross-Sectional Study

Epidemiological studies have suggested the role of multiple genetic and environmental factors in the development of non-neoplastic gastrointestinal (GI) diseases; however, little information is available on these factors in the Korean population. Therefore, this cross-sectional study explored the effect of these factors by analyzing the concordance of several benign GI disorders in 525 monozygotic twins compared to that in 122 dizygotic twins aged >20 years from the Healthy Twin Study data of the Korean Genome and Epidemiology Study (2005-2014). Chi-square test, Wilcoxon rank-sum, and binomial and multinomial logistic regression models were used for statistical analysis. There was lack of concordance of gastric/duodenal ulcers and cholelithiasis/cholangitis between monozygotic twins compared to that in dizygotic twins, suggesting that environmental factors may mediate those concordant disease expressions in monozygotic twins. The concordance of intestinal polyps in monozygotic twins was 32% lower than that in dizygotic twins (p = 0.028), indicating that the effect of genetic factors on the risk for intestinal polyp development may be low. In conclusion, the lack or low concordance of several benign GI diseases between monozygotic and dizygotic twin groups suggests the relative importance of environmental factors, indicating that these are preventable diseases.

Clinical Manifestations and Genetic Influences in Sulfonamide-Induced Hypersensitivity

Drug hypersensitivity is an inflammatory or immune reaction induced by drugs. It can be fatal if not appropriately treated and cause the risk of long-term complications. Sulfonamides are classified as antimicrobial drugs with a broad spectrum effective for gram-positive and gram-negative bacteria. This antibacterial agent works by competitively inhibiting folic acid synthesis, which prevents the growth and proliferation of microorganisms. In its use as antibiotics, sulfonamides can also cause adverse reactions in specific individuals. It has been widely reported that sulfonamide antimicrobials cause hypersensitivity reactions mediated by IgE or T cells. This review identifies symptoms or signs that can appear, as well as genes associated with sulfonamide hypersensitivity reactions, as sulfonamide may cause hypersensitivity in the form of uveitis, skin rash, Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN), parotitis, angioedema, drug reaction with eosinophilia and systemic symptoms (DRESS), and pruritus. In addition, several genes were found to be associated with sulfonamide hypersensitivity, including HLA-A29, HLA-B12, HLA-DR7, HLA-B44, and HLA A*11:01.

Nutrients, Genetic Factors, and Their Interaction in Non-Alcoholic Fatty Liver Disease and Cardiovascular Disease

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in Western countries and expose patients to increased risk of hepatic and cardiovascular (CV) morbidity and mortality. Both environmental factors and genetic predisposition contribute to the risk. An inappropriate diet, rich in refined carbohydrates, especially fructose, and saturated fats, and poor in fibers, polyunsaturated fats, and vitamins is one of the main key factors, as well as the polymorphism of patatin-like phospholipase domain containing 3 (PNPLA3 gene) for NAFLD and the apolipoproteins and the peroxisome proliferator-activated receptor (PPAR) family for the cardiovascular damage. Beyond genetic influence, also epigenetics modifications are responsible for various clinical manifestations of both hepatic and CV disease. Interestingly, data are accumulating on the interplay between diet and genetic and epigenetic modifications, modulating pathogenetic pathways in NAFLD and CV disease. We report the main evidence from literature on the influence of both macro and micronutrients in NAFLD and CV damage and the role of genetics either alone or combined with diet in increasing the risk of developing both diseases. Understanding the interaction between metabolic alterations, genetics and diet are essential to treat the diseases and tailoring nutritional therapy to control NAFLD and CV risk.

Early classroom reading gains moderate shared environmental influences on reading comprehension in adolescence

BACKGROUND

Reading is important for children's success in school and beyond, yet many adolescents fail to reach expected levels of proficiency. This highlights the need to better understand the factors that influence reading effectiveness over time, including genes and environment. Greater expression of genetic influence on first- and second-grade reading fluency has been observed in higher quality classroom reading environments. To what degree this early environment continues to influence genetic and other environmental influences on later reading is unknown and was tested in this study.

METHODS

The quality of the early classroom reading environment was approximated by gains in oral reading fluency (ORF) across the school year among first- or second-grade classmates of 546 MZ and 1,016 DZ twin children (mean age = 7.13 years; SD = 0.45) who had reading comprehension scores from a state-wide mandatory test in school year 2013-2014 when most twin pairs were in seventh to tenth grade (mean age = 14.41; SD = 1.13) in a variable called Class ORF Gain. Biometrical models were fit to the data to assess whether Class ORF Gain moderated the genetic, shared environmental and/or nonshared environmental variance associated with adolescent reading comprehension.

RESULTS

Class ORF Gain moderated shared environmental influences on reading comprehension 6-9 years later. When early classroom reading gains were poor, variability in reading comprehension in adolescence was high and was associated largely with shared environmental influences. When early classroom reading gains were good, overall and shared environmentally influenced variability in adolescent reading comprehension was lower so that genetic influences were most relevant in explaining that variability.

CONCLUSIONS

Our findings suggested that classroom reading environment experienced when children were learning to read had a lasting influence on the factors underlying variability in later reading effectiveness.

The influence of host genetics on the microbiome

It is well understood that genetic differences among hosts contribute to variation in pathogen susceptibility and the ability to associate with symbionts. However, it remains unclear just how influential host genes are in shaping the overall microbiome. Studies of both animal and plant microbial communities indicate that host genes impact species richness and the abundances of individual taxa. Analyses of beta diversity (that is, overall similarity), on the other hand, often conclude that hosts play a minor role in shaping microbial communities. In this review, we discuss recent attempts to identify the factors that shape host microbial communities and whether our understanding of these communities is affected by the traits chosen to represent them.

Weak Genetic Explanation 20 Years Later: Reply to Plomin et al. (2016)

Plomin, DeFries, Knopik, and Neiderhiser (2016, this issue) are correct in their assertion that many discoveries of behavior genetics have proven to be robust and replicable. I note, in contrast, that more specific assertions about the role of genetics in the development of behavior have failed to replicate. Reflecting on why more general findings replicate better than specific ones sheds light on the difficulties of studying complex human development and on the role played by genes in determining its course.

Why some children with externalising problems develop internalising symptoms: testing two pathways in a genetically sensitive cohort study

BACKGROUND

Children with externalising problems are at risk of developing internalising problems as they grow older. The pathways underlying this developmental association remain to be elucidated. We tested two processes that could explain why some children with externalising problems develop internalising symptoms in preadolescence: a mediation model whereby the association between early externalising and later new internalising symptoms is explained by negative experiences; and a genetic model, whereby genes influence both problems.

METHODS

We used data from the Environmental Risk (E-Risk) Study, a 1994-1995 birth cohort of 2,232 twins born in England and Wales. We assessed externalising and internalising problems using combined mothers' and teachers' ratings at age 5 and 12. We measured bullying victimisation, maternal dissatisfaction and academic difficulties between age 7 and 10 and used linear regression analyses to test the effects of these negative experiences on the association between early externalising and later internalising problems. We employed a Cholesky decomposition to examine the genetic influences on the association.

RESULTS

Children with externalising problems at age 5 showed increased rates of new internalising problems at age 12 (r = .24, p < .001). Negative experiences accounted for some of the association between early externalising and later internalising problems. Behavioural-genetic analyses indicated that genes influencing early externalising problems also affected later internalising problems.

CONCLUSIONS

Our findings highlight the role of genetic influences in explaining why some children with externalising problems develop internalising symptoms in preadolescence. Negative experiences also contribute to the association, possibly through gene-environment interplay. Mental health professionals should monitor the development of internalising symptoms in young children with externalising problems.

The cortisol awakening response and major depression: examining the evidence

A vast body of literature has revealed that dysregulation of the hypothalamic-pituitary-adrenal (HPA) stress axis is associated with etiology of major depressive disorder (MDD). There are many ways that the dysregulation of the HPA axis can be assessed: by sampling diurnal basal secretion and/or in response to a stress task, pharmacological challenge, and awakening. Here, we focus on the association between cortisol awakening response (CAR), as one index of HPA axis function, and MDD, given that the nature of this association is particularly unclear. Indeed, in the following selective review, we attempt to reconcile sometimes-divergent evidence of the role of CAR in the pathway to depression. We first examine association of CAR with psychological factors that have been linked with increased vulnerability to develop depression. Then, we summarize the findings regarding the CAR profile in those with current depression, and evaluate evidence for the role of CAR following depression resolution and continued vulnerability. Finally, we showcase longitudinal studies showing the role of CAR in predicting depression onset and recurrence. Overall, the studies reveal an important, but complex, association between CAR and vulnerability to depression.

GNB3 and FTO Polymorphisms and Pregnancy Weight Gain in Black Women

BACKGROUND

Gestational weight gain (GWG) is a modifiable risk factor for obesity in women. Black women have the greatest prevalence of high body mass, which predisposes them to excessive GWG. Increased understanding of genetic influences on GWG has implications for the health of women. The purpose of this study was to explore the associations of GNB3 and FTO risk alleles in pregnant women with prepregnancy body mass index (BMI), GWG, and postpartum and infant birth weights.

RESEARCH DESIGN AND METHODS

This was an observational, prospective candidate gene association study. Pregnant, low-income Black women (N = 97) were enrolled in early pregnancy and followed until 6 months postpartum.

RESULTS

GWG differed depending on number of FTO risk alleles. The mean 6-month postpartum BMI differed, although not significantly, by 4 kg/m(2) between homozygous women. There was an interaction between the FTO risk allele and prepregnancy BMI (p = .022), with obese homozygote AA women having significantly higher mean GWG than obese TT women. When controlling for age and smoking, the FTO gene and physical activity predicted GWG (p = .032). Although not statistically significant, women who carried the GNB3 T risk allele gained 6 pounds more than noncarriers, and mean 6-month postpartum BMI differed by 2.2 kg/m(2) between homozygous women. Neither the GNB3 nor FTO gene predicted prepregnancy BMI, infant birth weight, or postpartum weight.

CONCLUSION

Obese women homozygous for the FTO risk allele were at greater risk of excessive GWG compared to nonrisk allele homozygous obese women or nonobese women. This study provides evidence of the FTO gene's effect on GWG in Black women.