Modification of the association between diabetes and birth defects by obesity, National Birth Defects Prevention Study, 1997-2011

Genetic and environmental factors driving congenital solitary functioning kidney

BACKGROUND

Congenital solitary functioning kidney (CSFK) is an anomaly predisposing to hypertension, albuminuria and chronic kidney disease. Its aetiology is complex and includes genetic and environmental factors. The role of gene-environment interactions (G×E), although relevant for other congenital anomalies, has not yet been investigated. Therefore, we performed a genome-wide G×E analysis with six preselected environmental factors to explore the role of these interactions in the aetiology of CSFK.

METHODS

In the AGORA (Aetiologic research into Genetic and Occupational/environmental Risk factors for Anomalies in children) data- and biobank, genome-wide single-nucleotide variant (SNV) data and questionnaire data on prenatal exposure to environmental risk factors were available for 381 CSFK patients and 598 healthy controls. Using a two-step strategy, we first selected independent significant SNVs associated with one of the six environmental risk factors. These SNVs were subsequently tested in G×E analyses using logistic regression models, with Bonferroni-corrected P-value thresholds based on the number of SNVs selected in step one.

RESULTS

In step one, 7-40 SNVs were selected per environmental factor, of which only rs3098698 reached statistical significance (P = .0016, Bonferroni-corrected threshold 0.0045) for interaction in step two. The interaction between maternal overweight and this SNV, which results in lower expression of the Arylsulfatase B (ARSB) gene, could be explained by lower insulin receptor activity in children heterozygous for rs3098698. Eight other G×E interactions had a P-value <.05, of which two were biologically plausible and warrant further study.

CONCLUSIONS

Interactions between genetic and environmental factors may contribute to the aetiology of CSFK. To better determine their role, large studies combining data on genetic and environmental risk factors are warranted.

Maternal Gestational Diabetes Mellitus and Congenital Heart Disease in Offspring: A Meta-Analysis

Maternal diabetes has been related to an increased risk of congenital heart disease (CHD) in offspring. However, inconsistent results were retrieved for studies evaluating the association between gestational diabetes mellitus (GDM) and CHD in offspring. We therefore performed a systematic review and meta-analysis for comprehensive investigation. Observational studies were identified by searching PubMed, Embase, and Web of Science according to the aim of the meta-analysis. A randomized-effects model was used to pool the data by incorporating the influence of potential heterogeneity. Twenty-three observational studies, involving 46953078 mother-child pairs, were available for the meta-analysis. Among them, 2131800 mothers were diagnosed as GDM and 214379 newborns had CHD. Overall, maternal GDM was associated with a higher incidence of CHD in offspring [odds ratio (OR): 1.32, 95% confidence interval (CI): 1.21 to 1.45, p<0.001; I2=62%]. Sensitivity analysis limited to studies with adjustment of maternal age and other potential confounding factors showed similar results (OR: 1.40, 95% CI: 1.30 to 1.51, p<0.001; I2=47%). Subgroup analysis suggested that the association between maternal GDM and CHD in offspring was not significantly affected by methods for diagnosis of GDM, methods for confirmation of CHD, or study quality scores (p for subgroup difference all>0.05). Subsequent analysis according to types of CHD showed that maternal GDM was associated with higher risks of atrial septal defect, ventricular septal defect, and Tetralogy of Fallot. Maternal GDM may be associated with a higher risk of CHD in offspring.

Hypoplastic Left Heart Syndrome: Signaling & Molecular Perspectives, and the Road Ahead

Hypoplastic left heart syndrome (HLHS) is a lethal congenital heart disease (CHD) affecting 8-25 per 100,000 neonates globally. Clinical interventions, primarily surgical, have improved the life expectancy of the affected subjects substantially over the years. However, the etiological basis of HLHS remains fundamentally unclear to this day. Based upon the existing paradigm of studies, HLHS exhibits a multifactorial mode of etiology mediated by a complicated course of genetic and signaling cascade. This review presents a detailed outline of the HLHS phenotype, the prenatal and postnatal risks, and the signaling and molecular mechanisms driving HLHS pathogenesis. The review discusses the potential limitations and future perspectives of studies that can be undertaken to address the existing scientific gap. Mechanistic studies to explain HLHS etiology will potentially elucidate novel druggable targets and empower the development of therapeutic regimens against HLHS in the future.

Epidemiology of birth defects based on a birth defects surveillance system in southwestern China and the associated risk factors

Background

Birth defects (BDs) are associated with many potential risk factors, and its causes are complex.

Objectives

This study aimed to explore the epidemiological characteristics of BDs in Guangxi of China and the associated risk factors of BDs.

Methods

BDs data of perinatal infants (PIs) were obtained from the Guangxi birth defects monitoring network between 2016 and 2020. Univariate Poisson regression was used to calculate the prevalence-rate ratios (PRR) to explore the changing trends of BDs prevalence by year and the correlation between the regarding of characteristics of BDs (including infant gender, maternal age, and quarter) and BDs. Clinical characteristics of PIs with BDs and general characteristics of their mothers were documented, and Spearman correlation analysis was used to explore the potential associated risk factors of BDs.

Results

Between 2016 and 2020, 44,146 PIs with BDs were monitored, with an overall BDs prevalence of 121.71 (95% CI: 120.58-122.84) per 10,000 PIs, showing a significant increase trend (PRR = 1.116, 95% CI: 1.108-1.123), especially the prevalence of congenital heart defects (CHDs) that most significantly increased (PRR = 1.300, 95% CI: 1.283-1.318). The 10 most common BDs were CHDs, polydactyly, congenital talipes equinovarus, other malformation of external ear, syndactyly, hypospadias, cleft lip with cleft palate, cleft lip, hemoglobin Bart's hydrops fetalis syndrome (BHFS), and congenital atresia of the rectum and anus. BDs were positively correlated with pregnant women's age (R = 0.732, P < 0.01) and education level (R = 0.586, P < 0.05) and having pre-gestational diabetes mellitus (PGDM)/gestational diabetes mellitus (GDM) (R = 0.711, P < 0.01), while when the pregnant women had a family history of a dead fetus (R = -0.536, P < 0.05) and a birth of a fetus with BDs (R = -0.528, P < 0.05) were negatively correlated with BDs.

Conclusion

A significant increase in the prevalence of BDs was detected between 2016 and 2020 in Guangxi, especially the prevalence of CHDs that most significantly increased. Older maternal age, higher maternal education level, and having PGDM before pregnancy or GDM in early pregnancy were the risk factors for BDs.

Folate Supplementation in Women with Pre-Existing Diabetes

Folate supplementation in the periconceptual period is the standard of care for the prevention of neural tube defects. To support dietary folate intake, some countries have introduced mandatory folic acid fortification of food products. Robust evidence supports the additional use of a low-dose folic acid supplement (0.4 mg/day) in all women from 2-3 months preconception until the end of the 12th week of gestation. For women with pre-existing diabetes, high-dose folic acid supplementation (5 mg/day) is recommended in some, but not all international guidelines. The recommendation is made based on consensus opinion and reflects the increased risk of neural tube defects in pregnant women with pre-existing diabetes. However, there is limited evidence to clarify the high-risk groups that benefit from high-dose folic acid versus those that do not. There are also some data to suggest that high-dose folic acid may be harmful to mothers and offspring, although this issue remains controversial. This narrative review explores the evidence that supports the recommendation for women with pre-existing diabetes to take high-dose folic acid in the periconceptual period. It explores the potential benefits of high-dose supplemental folate beyond the prevention of neural tube defects, and also the potential adverse impacts of high-dose folate use. These topics are considered with a specific focus on the issues that are pertinent to women with pre-existing diabetes. Based on the available evidence, a pragmatic approach to the use of folic acid supplements in women with pre-existing diabetes during the periconception period is suggested. The need for comprehensive preconception care that optimises glycaemic control and addresses other modifiable risk factors before pregnancy is emphasized.

Environmental and parental risk factors for congenital solitary functioning kidney - a case-control study

BACKGROUND

The etiology of congenital solitary functioning kidney (CSFK) is largely unknown but likely includes various risk factors. We performed a case-control study to compare exposure to environmental and parental risk factors during embryonic kidney development between children with CSFK and healthy controls.

METHODS

We included 434 children with CSFK and 1302 healthy controls from the AGORA data- and biobank matched on year of birth. Exposure to potential risk factors was investigated using parental questionnaire data. Crude and adjusted odds ratios (aORs) with 95% confidence intervals (CIs) were estimated for each potential risk factor. Multiple imputation was used to deal with missing values. Confounders for each potential risk factor were selected using directed acyclic graphs.

RESULTS

Maternal stress was newly identified as a risk factor for CSFK (aOR 2.1, 95% CI 1.2-3.5). Known associations with conception using in vitro fertilization/intracytoplasmic sperm injection (aOR 1.8, 95% CI 1.0-3.2), maternal infections during pregnancy (aOR 2.5, 95% CI 1.4-4.7), smoking during pregnancy (aOR 1.4, 95% CI 1.0-2.0), and parental CAKUT (aOR 6.6, 95% CI 2.9-15.1) were confirmed, but previous associations with diabetes and obesity could not be replicated. Folic acid supplement use and younger maternal age seemed to reduce the risk of CSFK (aORs 0.7, 95% CI 0.5-1.0, and 0.8, 95% CI 0.6-1.0, respectively).

CONCLUSIONS

Environmental and parental risk factors are likely to be involved in the development of CSFK and future studies should combine genetic, environmental, and gene-environment interaction analyses. Women wanting to become pregnant should consider optimizing their health and lifestyle. A higher-resolution version of the Graphical abstract is available as Supplementary information.

Endocardium in Hypoplastic Left Heart Syndrome: Implications from In Vitro Study

Endocardium lines the inner layer of the heart ventricle and serves as the source of valve endothelial cells and interstitial cells. Previously, endocardium-associated abnormalities in hypoplastic left heart syndrome (HLHS) have been reported, including endocardial fibroelastosis (EFE) and mitral and aortic valve malformation. However, few mechanistic studies have investigated the molecular pathological changes in endocardial cells. Recently, the emergence of a powerful in vitro system-induced pluripotent stem cells (iPSCs)-was applied to study various genetic diseases, including HLHS. This review summarized current in vitro studies in understanding the endocardial pathology in HLHS, emphasizing new findings of the cellular phenotypes and underlying molecular mechanisms. Lastly, a future perspective is provided regarding the better recapitulation of endocardial phenotypes in a dish.

Considering the Genetic Architecture of Hypoplastic Left Heart Syndrome

Hypoplastic left heart syndrome (HLHS) is among the most severe cardiovascular malformations and understanding its causes is crucial to making progress in prevention and treatment. Genetic analysis is a broadly useful tool for dissecting complex causal mechanisms and it is playing a significant role in HLHS research. However, unlike classical Mendelian disorders where a relatively small number of genes are largely determinative of the occurrence and severity of the disease, the picture in HLHS is complex. De novo single-gene and copy number variant (CNV) disorders make an important contribution, but there is emerging evidence for causal contributions from lower penetrance and common variation. Integrating this emerging knowledge into clinical diagnostics and translating the findings into effective prevention and treatment remain challenges for the future.