The association of elevated maternal genetic risk scores for hypertension, type 2 diabetes and obesity and having a child with a congenital heart defect

Association of maternal hypertension and diabetes with variants of the NKX2-5, LEFTY1 and LEFTY2 genes in children with congenital heart defects: a case-control study from Pakistani Population

BACKGROUND

Globally, congenital heart defect (CHD) is the most common congenital malformation, responsible for higher morbidity and mortality in the pediatric population. It is a complex multifactorial disease influenced by gene-environment and gene-gene interactions. The current study was the first attempt to study these polymorphisms in common clinical phenotypes of CHD in Pakistan and the association between maternal hypertension and diabetes with single nucleotide polymorphisms (SNPs) in children.

METHODS

A total of 376 subjects were recruited in this current case-control study. Six variants from three genes were analyzed by cost-effective multiplex PCR and genotyped by minisequencing. Statistical analysis was done by GraphPad prism and Haploview. The association of SNPs and CHD was determined using logistic regression.

RESULTS

The risk allele frequency was higher in cases as compared to healthy subjects, but the results were not significant for rs703752. However, stratification analysis suggested that rs703752 was significantly associated with the tetralogy of Fallot. The rs2295418 was significantly associated with maternal hypertension (OR = 16.41, p = 0.003), while a weak association was present between maternal diabetes and rs360057 (p = 0.08).

CONCLUSION

In conclusion, variants in transcriptional and signaling genes were associated with Pakistani pediatric CHD patients that showed varied susceptibility between different clinical phenotypes of CHD. In addition, this study was the first report regarding the significant association between maternal hypertension and the LEFTY2 gene variant.

Maternal genetic factors in the development of congenital heart defects

Congenital heart defects (CHDs) are among the most common, serious birth defects. However, the cause of CHDs is unknown for approximately half of affected individuals and there are few prevention strategies. Although not extensively investigated, maternal genes may contribute to CHD etiology by modifying the effects of maternal exposures (e.g. medications, nutrients), contributing to maternal phenotypes that are associated with an increased risk of CHDs in offspring (e.g. diabetes), or acting as maternal effect genes. Since maternal genes could serve as a target for the primary prevention of CHDs, efforts to further define the contribution of the maternal genome to CHD etiology are warranted.

The Impact of Maternal Obesity on Offspring Cardiovascular Health: A Systematic Literature Review

Objective

Obesity and cardiovascular disease are major global public health problems. Maternal obesity has been linked to multiple adverse health consequences for both mother and baby. Obesity during pregnancy may adversely alter the intrauterine environment, which has been hypothesised to predispose the offspring to poorer cardiovascular health throughout life. In this paper, we systematically review current literature examining the links between maternal obesity and offspring cardiovascular health.

Methods

This study is registered with PROSPERO (CRD42021278567) and was conducted in accordance with the PRISMA guidelines. A comprehensive systematic literature search was conducted, including two electronic databases (Ovid Medline, Embase), cross-referencing, author searching, and grey literature searches. We selected studies exploring the relationship between maternal obesity and offspring cardiovascular health, using pre-defined eligibility criteria. Studies were critically appraised using the ROBINS-I tool.

Results

From 1,214 results, 27 articles met the eligibility criteria. Multiple cardiovascular outcomes were considered, including congenital heart disease, cardiometabolic parameters, and cardiovascular diseases in neonates, children, and adults. In these studies, maternal obesity was consistently associated with congenital heart disease, several adverse cardiometabolic parameters throughout life including higher body mass index and insulin levels, and greater risk of cardiovascular disease in adulthood. Hypothesized underlying mechanisms are complex and multifactorial comprising genetic, environmental, and socioeconomic components, which can be difficult to quantify. Heterogeneity in study designs, highly selected study samples, and high risk of bias in some studies limit conclusions regarding causality.

Conclusions

We identified consistent evidence of links between maternal obesity and poorer offspring cardiovascular health throughout the lifecourse, extending from the neonatal period into adulthood. Although underlying mechanisms are unclear, our findings support consideration of targeted maternal obesity prevention for promotion of offspring cardiovascular health. This all-encompassing systematic review provides critical appraisal of the latest evidence, defines gaps and biases of existing literature, and may inform potential new public health strategies for cardiovascular disease prevention.

Systematic Review Registration

[https://www.crd.york.ac.uk/prospero], identifier PROSPERO (CRD42021278567).

Genome-Wide De Novo Variants in Congenital Heart Disease Are Not Associated With Maternal Diabetes or Obesity

BACKGROUND

Congenital heart disease (CHD) is the most common anomaly at birth, with a prevalence of ≈1%. While infants born to mothers with diabetes or obesity have a 2- to 3-fold increased incidence of CHD, the cause of the increase is unknown. Damaging de novo variants (DNV) in coding regions are more common among patients with CHD, but genome-wide rates of coding and noncoding DNVs associated with these prenatal exposures have not been studied in patients with CHD.

METHODS

DNV frequencies were determined for 1812 patients with CHD who had whole-genome sequencing and prenatal history data available from the Pediatric Cardiac Genomics Consortium's CHD GENES study (Genetic Network). The frequency of DNVs was compared between subgroups using t test or linear model.

RESULTS

Among 1812 patients with CHD, the number of DNVs per patient was higher with maternal diabetes (76.5 versus 72.1, t test P=3.03×10^-11), but the difference was no longer significant after including parental ages in a linear model (paternal and maternal correction P=0.42). No interaction was observed between diabetes risk and parental age (paternal and maternal interaction P=0.80 and 0.68, respectively). No difference was seen in DNV count per patient based on maternal obesity (72.0 versus 72.2 for maternal body mass index <25 versus maternal body mass index >30, t test P=0.86).

CONCLUSIONS

After accounting for parental age, the offspring of diabetic or obese mothers have no increase in DNVs compared with other children with CHD. These results emphasize the role for other mechanisms in the cause of CHD associated with these prenatal exposures.

REGISTRATION

URL: https://clinicaltrials.gov; NCT01196182.

Maternal Hypertension-Related Genotypes and Congenital Heart Defects

BACKGROUND

Maternal hypertension has been associated with congenital heart defect occurrence in several studies. We assessed whether maternal genotypes associated with this condition were also associated with congenital heart defect occurrence.

METHODS

We used data from the National Birth Defects Prevention Study to identify non-Hispanic white (NHW) and Hispanic women with (cases) and without (controls) a pregnancy in which a select simple, isolated heart defect was present between 1999 and 2011. We genotyped 29 hypertension-related single nucleotide polymorphisms (SNPs). We conducted logistic regression analyses separately by race/ethnicity to assess the relationship between the presence of any congenital heart defect and each SNP and an overall blood pressure genetic risk score (GRS). All analyses were then repeated to assess 4 separate congenital heart defect subtypes.

RESULTS

Four hypertension-related variants were associated with congenital heart defects among NHW women (N = 1,568 with affected pregnancies). For example, 1 intronic variant in ARHGAP2, rs633185, was associated with conotruncal defects (odds ratio [OR]: 1.3, 95% confidence interval [CI]: 1.1-1.6). Additionally, 2 variants were associated with congenital heart defects among Hispanic women (N = 489 with affected pregnancies). The GRS had a significant association with septal defects (OR: 2.1, 95% CI: 1.2-3.5) among NHW women.

CONCLUSIONS

We replicated a previously reported association between rs633185 and conotruncal defects. Although additional hypertension-related SNPs were also associated with congenital heart defects, more work is needed to better understand the relationship between genetic risk for maternal hypertension and congenital heart defects occurrence.

Adverse pregnancy outcomes associated with first-trimester exposure to angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers: A systematic review and meta-analysis

This study aimed to determine the effects of prenatal exposure to angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs), particularly when exposure is limited to the first trimester of pregnancy, on adverse maternal and neonatal outcomes. A systematic search was performed on four databases, that is, PubMed, Scopus, Web of Science, and Cochrane Library, to identify relevant articles published up to December 31, 2019. Included studies were limited to original investigations assessing the association between prenatal exposure to ACEIs/ARBs and adverse pregnancy outcomes. Odds ratios were used as a summary effect measure. Pooled-effect estimates of each outcome were calculated by the random-effects meta-analysis. The main outcomes included overall and specific congenital malformations, low birth weight, miscarriage, elective termination of pregnancy, stillbirth, and preterm delivery. Of 19 included articles involving a total of 4 163 753 pregnant women, 13 studies reported an increased risk of, at least, one adverse pregnancy outcome in pregnant women who were exposed to ACEIs/ARBs. Meta-analysis revealed a significant association between overall congenital malformations and first trimester-only exposure to ACEIs/ARBs (OR = 1.94, 95% CI = 1.71-2.21, P < .0001). Cardiovascular malformations, miscarriage, and stillbirth also provided a significant relation with ACEI/ARB exposure. In conclusion, prenatal exposure to ACEIs/ARBs in the first trimester of pregnancy was found to be associated with an increased risk of adverse pregnancy outcomes. Women of reproductive age should be aware of the potential teratogenic risks of these drugs if they become pregnant.

Gene-based analyses of the maternal genome implicate maternal effect genes as risk factors for conotruncal heart defects

Congenital heart defects (CHDs) affect approximately 1% of newborns. Epidemiological studies have identified several genetically-mediated maternal phenotypes (e.g., pregestational diabetes, chronic hypertension) that are associated with the risk of CHDs in offspring. However, the role of the maternal genome in determining CHD risk has not been defined. We present findings from gene-level, genome-wide studies that link CHDs to maternal effect genes as well as to maternal genes related to hypertension and proteostasis. Maternal effect genes, which provide the mRNAs and proteins in the oocyte that guide early embryonic development before zygotic gene activation, have not previously been implicated in CHD risk. Our findings support a role for and suggest new pathways by which the maternal genome may contribute to the development of CHDs in offspring.