Gender difference in interactions between MAOA promoter uVNTR polymorphism and negative familial stressors on body mass index among Chinese adolescents

Gestational Weight Gain: Is the Role of Genetic Variants a Determinant? A Review

Excessive or insufficient gestational weight gain (GWG) leads to diverse adverse maternal and neonatal outcomes. There is evidence that pregestational body mass index (pBMI) plays a role in GWG, but no genetic cause has been identified. In this review, we aim to analyze genotype variants associated with GWG. Results: We identified seven genotype variants that may be involved in GWG regulation that were analyzed in studies carried out in Brazil, Romania, the USA, Turkey, Ukraine, and Canada. Some genetic variants were only associated with GWG in certain races or depending on the pBMI. In women who were obese or overweight before gestation, some genetic variants were associated with GWG. Environmental and genetic factors together showed a greater association with GWG than genetic factors alone; for example, type of diet was observed to have a significant influence. Conclusions: We found little scientific evidence of an association between genotype variants in countries with a high prevalence of women of reproductive age who are overweight and obese, such as in Latin America. GWG may be more dependent on environmental factors than genetic variants. We suggest a deeper study of genetic variants, cytokines, and their possible association with GWG, always with the respective control of potential cofounding factors, such as pBMI, diet, and race.

ADHD co-morbidities: A review of implication of gene × environment effects with dopamine-related genes

ADHD is a major burden in adulthood, where co-morbid conditions such as depression, substance use disorder and obesity often dominate the clinical picture. ADHD has substantial shared heritability with other mental disorders, contributing to comorbidity. However, environmental risk factors exist but their interaction with genetic makeup, especially in relation to comorbid disorders, remains elusive. This review for the first time summarizes present knowledge on gene x environment (GxE) interactions regarding the dopamine system. Hitherto, mainly candidate (GxE) studies were performed, focusing on the genes DRD4, DAT1 and MAOA. Some evidence suggest that the variable number tandem repeats in DRD4 and MAOA may mediate GxE interactions in ADHD generally, and comorbid conditions specifically. Nevertheless, even for these genes, common variants are bound to suggest risk only in the context of gender and specific environments. For other polymorphisms, evidence is contradictory and less convincing. Particularly lacking are longitudinal studies testing the interaction of well-defined environmental with polygenic risk scores reflecting the dopamine system in its entirety.

The contribution of recently identified adult BMI risk loci to paediatric obesity in a Singaporean Chinese childhood dataset

INTRODUCTION

Recent genome-wide association studies have identified 103 adult obesity risk loci; however, it is unclear if these findings are relevant to East-Asian childhood body mass index (BMI) levels.

METHODS AND RESULTS

We evaluated for paediatric obesity associations at these risk loci utilizing genome-wide data from Chinese childhood subjects in the Singapore Cohort study Of the Risk factors for Myopia study (N = 1006). A weighted gene-risk score of all adult obesity risk loci in the Singapore Cohort study Of the Risk factors for Myopia study showed strong associations with BMI at age 9 (p-value = 3.40 × 10^-12 ) and 4-year average BMI (age 9 to 12, p-value = 6.67 × 10^-8 ). Directionally consistent nominal associations for 15 index single nucleotide polymorphisms (SNPs) (p-value < 0.05) were observed. Pathway analysis with genes from these 15 replicating loci revealed over-representation for the G-protein-coupled receptor (GPCR)-mediated integration of entero-endocrine signalling pathway exemplified by L-cell (adjusted p-value = 0.018). Evaluations of birth weight to modify the effects of BMI risk SNPs in paediatric obesity did not reveal significant interactions, and these SNPs were generally not associated with birth weight.

CONCLUSIONS

At least some common adult BMI risk variants predispose to paediatric obesity risk in East-Asians.

Genetic and epigenetic associations to obesity-related appetite phenotypes among African-American children

BACKGROUND

Genetic and epigenetic variations may be an important contributer to altered eating behaviors in childhood which may lead to weight gain and obesity later in life.

OBJECTIVE

This study aimed to evaluate epigenetic as well as genetic associations with appetite in young children.

SUBJECTS AND METHODS

Participants were 32 non-obese and 32 obese African-American children aged 5-6 years. Saliva was collected from each child, and RNA and DNA were extracted for analysis. Individuals were genotyped for eating- and obesity-associated single nucleotide polymorphisms in seven candidate genes (FTO, MAOA, SH2B1, LEPR, DNMT3B, BDNF and CCKAR), and DNA methylation levels were measured in the upstream promoter region of each. Transcript levels of MAOA and FTO were also assessed. The Children's Eating Behavior Questionnaire (CEBQ) was used to assess the aspects of appetite. Child obesity was assessed using measured height and weight, and percent body fat was measured by dual-energy X-ray absorptiometry.

RESULTS

Food responsiveness was higher and satiety responsiveness was lower among obese than non-obese female children (P = 0.001 and P = 0.031), but did not differ among male children. Epigenetic analysis of the BDNF promoter revealed associations with altered satiety responsiveness among female children (P < 0.01).

CONCLUSION

The findings provide new evidence of epigenetic associations with altered appetite among young African-American girls.