Shared genetic risk between major orofacial cleft phenotypes in an African population.

Nonsyndromic orofacial clefts (NSOFCs) represent a large proportion (70%-80%) of all OFCs. They can be broadly categorized into nonsyndromic cleft lip with or without cleft palate (NSCL/P) and nonsyndromic cleft palate only (NSCPO). Although NSCL/P and NSCPO are considered etiologically distinct, recent evidence suggests the presence of shared genetic risks. Thus, we investigated the genetic overlap between NSCL/P and NSCPO using African genome-wide association study (GWAS) data on NSOFCs. These data consist of 814 NSCL/P, 205 NSCPO cases, and 2159 unrelated controls. We generated common single-nucleotide variants (SNVs) association summary statistics separately for each phenotype (NSCL/P and NSCPO) under an additive genetic model. Subsequently, we employed the pleiotropic analysis under the composite null (PLACO) method to test for genetic overlap. Our analysis identified two loci with genome-wide significance (rs181737795 [p = 2.58E-08] and rs2221169 [p = 4.5E-08]) and one locus with marginal significance (rs187523265 [p = 5.22E-08]). Using mouse transcriptomics data and information from genetic phenotype databases, we identified MDN1, MAP3k7, KMT2A, ARCN1, and VADC2 as top candidate genes for the associated SNVs. These findings enhance our understanding of genetic variants associated with NSOFCs and identify potential candidate genes for further exploration.

Whole genome sequencing identifies associations for nonsyndromic sagittal craniosynostosis with the intergenic region of BMP2 and noncoding RNA gene LINC01428.

Craniosynostosis (CS) is a major birth defect resulting from premature fusion of cranial sutures. Nonsyndromic CS occurs more frequently than syndromic CS, with sagittal nonsyndromic craniosynostosis (sNCS) presenting as the most common CS phenotype. Previous genome-wide association and targeted sequencing analyses of sNCS have identified multiple associated loci, with the strongest association on chromosome 20. Herein, we report the first whole-genome sequencing study of sNCS using 63 proband-parent trios. Sequencing data for these trios were analyzed using the transmission disequilibrium test (TDT) and rare variant TDT (rvTDT) to identify high-risk rare gene variants. Sequencing data were also examined for copy number variants (CNVs) and de novo variants. TDT analysis identified a highly significant locus at 20p12.3, localized to the intergenic region between BMP2 and the noncoding RNA gene LINC01428. Three variants (rs6054763, rs6054764, rs932517) were identified as potential causal variants due to their probability of being transcription factor binding sites, deleterious combined annotation dependent depletion scores, and high minor allele enrichment in probands. Morphometric analysis of cranial vault shape in an unaffected cohort validated the effect of these three single nucleotide variants (SNVs) on dolichocephaly. No genome-wide significant rare variants, de novo loci, or CNVs were identified. Future efforts to identify risk variants for sNCS should include sequencing of larger and more diverse population samples and increased omics analyses, such as RNA-seq and ATAC-seq.

Rare Variants Analyses Suggest Novel Cleft Genes in the African Population.

Non-syndromic orofacial clefts (NSOFCs) are common birth defects with a complex etiology. While over 60 common risk loci have been identified, they explain only a small proportion of the heritability for NSOFC. Rare variants have been implicated in the missing heritability. Thus, our study aimed to identify genes enriched with nonsynonymous rare coding variants associated with NSOFCs. Our sample included 814 non-syndromic cleft lip with or without palate (NSCL/P), 205 non-syndromic cleft palate only (NSCPO), and 2150 unrelated control children from Nigeria, Ghana, and Ethiopia. We conducted a gene-based analysis separately for each phenotype using three rare-variants collapsing models: (1) protein-altering (PA), (2) missense variants only (MO); and (3) loss of function variants only (LOFO). Subsequently, we utilized relevant transcriptomics data to evaluate associated gene expression and examined their mutation constraint using the gnomeAD database. In total, 13 genes showed suggestive associations (p = E-04). Among them, eight genes (ABCB1, ALKBH8, CENPF, CSAD, EXPH5, PDZD8, SLC16A9, and TTC28) were consistently expressed in relevant mouse and human craniofacial tissues during the formation of the face, and three genes (ABCB1, TTC28, and PDZD8) showed statistically significant mutation constraint. These findings underscore the role of rare variants in identifying candidate genes for NSOFCs.

Associations between maternal periconceptional alcohol consumption and risk of omphalocele among offspring, National Birth Defects Prevention Study, 1997-2011.

OBJECTIVE: Previous studies of alcohol consumption during pregnancy and omphalocele have produced mixed results. We updated an earlier analysis of National Birth Defects Prevention Study (NBDPS) data, adding six years of participants, to examine associations between maternal alcohol consumption and omphalocele. METHODS: NBDPS was a multi-site, population-based case-control study in the United States. Cases were identified from birth defect surveillance programs in 10 states; controls were liveborn infants without a birth defect randomly selected from the same catchment areas. Mothers self-reported alcohol consumption during the periconceptional period (one month before through the third gestational month) via telephone interview. Our study included mothers of 410 omphalocele cases and 11,219 controls with estimated dates of delivery (EDDs) during 1997-2011. We used logistic regression to estimate adjusted odds ratios (AORs) and 95% confidence intervals (CIs) for periconceptional alcohol consumption and omphalocele. We performed a probabilistic bias analysis to evaluate the impact of alcohol exposure misclassification on our results. RESULTS: Overall, 44% of case and 38% of control mothers reported periconceptional alcohol consumption; 22% and 17%, respectively, reported binge drinking. Any maternal periconceptional alcohol consumption was associated with modestly increased odds of omphalocele (AOR 1.35, 95% CI 1.09, 1.68), as was binge drinking (AOR 1.47, 95% CI 1.08, 2.01). Our bias analysis yielded estimates further from the null. CONCLUSIONS: We observed modest associations between maternal periconceptional alcohol consumption and omphalocele. Based on our bias analysis, studies of alcohol and birth defects not accounting for exposure misclassification may underestimate associations.

Antifungal medication use during early pregnancy and the risk of congenital heart defects in the National Birth Defects Prevention Study, 1997-2011.

BACKGROUND: Fungal infections are common among pregnant people. Recent studies suggest positive associations between oral antifungals used to treat fungal infections and congenital heart defects (CHDs). METHODS: We estimated associations between first trimester antifungal use and 20 major, specific CHDs using data from the National Birth Defects Prevention Study (NBDPS), a multi-site, case-control study that included pregnancies with estimated delivery dates from October 1997 through December 2011. Infants with CHDs ("cases") were ascertained from 10 birth defect surveillance programs. Live born infants without major birth defects ("controls") were randomly selected from birth records or hospital discharge lists. First trimester antifungal use was self-reported via maternal interview. We estimated adjusted odds ratios (AORs) and 95% confidence intervals (CIs) using logistic regression with Firth's penalized likelihood. RESULTS: First trimester antifungal use was reported by 148/11,653 (1.3%) case and 123/11,427 (1.1%) control participants. We estimated AORs for 12 CHDs; six had AORs >1.5 (tetralogy of Fallot, double outlet right ventricle with transposition of the great arteries [DORV-TGA], atrioventricular septal defect, hypoplastic left heart syndrome, pulmonary atresia, muscular ventricular septal defect), and one (pulmonary valve stenosis) had an AOR <0.7. All CIs included the null, except for DORV-TGA. CONCLUSIONS: First trimester antifungal use was rare. We observed some positive associations for several specific CHDs in our analysis, although the CIs largely included the null. Results do not support a large increase in risk, but smaller increases in risk for certain CHD cannot be ruled out.

Prophylactic use of cardiac medications for delay of left ventricular dysfunction in Duchenne muscular dystrophy.

BACKGROUND: Epidemiological support for prophylactic treatment of left ventricular dysfunction (LVD) in Duchenne muscular dystrophy is limited. We used retrospective, population-based surveillance data from the Muscular Dystrophy Surveillance, Tracking and Research Network to evaluate whether prophylaxis delays LVD onset. METHODS: We analyzed 455 males born during 1982-2009. Age at first abnormal echocardiogram (ejection fraction <55% or shortening fraction <28%) determined LVD onset. Prophylaxis was defined as cardiac medication use at least 1 year prior to LVD. Corticosteroid use was also coded. Kaplan-Meier curve estimation and Cox Proportional Hazard modeling with time-varying covariates describe associations. RESULTS: LVD was identified among 40.7%; average onset age was 14.2 years. Prophylaxis was identified for 20.2% and corticosteroids for 57.4%. Prophylaxis showed delayed LVD onset (p < .001) and lower hazard of dysfunction (adjusted hazard ratio [aHR] = 0.39, 95%CL = 0.22, 0.65) compared to untreated. Compared to no treatment, continuous corticosteroids only (aHR = 1.01, 95%CL = 0.66, 1.53) and prophylaxis only (aHR = 0.67, 95%CL = 0.25, 1.50) were not cardioprotective, but prophylaxis plus continuous corticosteroids were associated with lower hazard of dysfunction (aHR = 0.37, 95%CL = 0.15, 0.80). CONCLUSIONS: Proactive cardiac treatment and monitoring are critical aspects of managing Duchenne muscular dystrophy. Consistent with clinical care guidelines, this study supports clinical benefit from cardiac medications initiated prior to documented LVD and suggests further benefit when combined with corticosteroids.

Scientific impact of the National Birth Defects Prevention Network multistate collaborative publications.

BACKGROUND: Given the lack of a national, population-based birth defects surveillance program in the United States, the National Birth Defects Prevention Network (NBDPN) has facilitated important studies on surveillance, research, and prevention of major birth defects. We sought to summarize NBDPN peer-reviewed publications and their impact. METHODS: We obtained and reviewed a curated list of 49 NBDPN multistate collaborative publications during 2000-2022, as of December 31, 2022. Each publication was reviewed and classified by type (e.g., risk factor association analysis). Key characteristics of study populations and analytic approaches used, along with publication impact (e.g., number of citations), were tabulated. RESULTS: NBDPN publications focused on prevalence estimates (N = 17), surveillance methods (N = 11), risk factor associations (N = 10), mortality and other outcomes among affected individuals (N = 6), and descriptive epidemiology of various birth defects (N = 5). The most cited publications were those that reported on prevalence estimates for a spectrum of defects and those that assessed changes in neural tube defects (NTD) prevalence following mandatory folic acid fortification in the United States. CONCLUSIONS: Results from multistate NBDPN publications have provided critical information not available through other sources, including US prevalence estimates of major birth defects, folic acid fortification and NTD prevention, and improved understanding of defect trends and surveillance efforts. Until a national birth defects surveillance program is established in the United States, NBDPN collaborative publications remain an important resource for investigating birth defects and informing decisions related to health services planning of secondary disabilities prevention and care.

Outcomes up to age 36 months after congenital Zika virus infection-U.S. states.

BACKGROUND: To characterize neurodevelopmental abnormalities in children up to 36 months of age with congenital Zika virus exposure. METHODS: From the U.S. Zika Pregnancy and Infant Registry, a national surveillance system to monitor pregnancies with laboratory evidence of Zika virus infection, pregnancy outcomes and presence of Zika associated birth defects (ZBD) were reported among infants with available information. Neurologic sequelae and developmental delay were reported among children with ≥1 follow-up exam after 14 days of age or with ≥1 visit with development reported, respectively. RESULTS: Among 2248 infants, 10.1% were born preterm, and 10.5% were small-for-gestational age. Overall, 122 (5.4%) had any ZBD; 91.8% of infants had brain abnormalities or microcephaly, 23.0% had eye abnormalities, and 14.8% had both. Of 1881 children ≥1 follow-up exam reported, neurologic sequelae were more common among children with ZBD (44.6%) vs. without ZBD (1.5%). Of children with ≥1 visit with development reported, 46.8% (51/109) of children with ZBD and 7.4% (129/1739) of children without ZBD had confirmed or possible developmental delay. CONCLUSION: Understanding the prevalence of developmental delays and healthcare needs of children with congenital Zika virus exposure can inform health systems and planning to ensure services are available for affected families. IMPACT: We characterize pregnancy and infant outcomes and describe neurodevelopmental abnormalities up to 36 months of age by presence of Zika associated birth defects (ZBD). Neurologic sequelae and developmental delays were common among children with ZBD. Children with ZBD had increased frequency of neurologic sequelae and developmental delay compared to children without ZBD. Longitudinal follow-up of infants with Zika virus exposure in utero is important to characterize neurodevelopmental delay not apparent in early infancy, but logistically challenging in surveillance models.

Antifungal medication use during pregnancy and the risk of selected major birth defects in the National Birth Defects Prevention Study, 1997-2011.

PURPOSE: Recent studies suggest increased birth defect risk associated with maternal use of specific oral antifungals. We estimated associations between first-trimester antifungal use and selected non-cardiac birth defects using National Birth Defects Prevention Study (NBDPS) data. METHODS: Participants with a pregnancy affected by a study-eligible birth defect ("cases") were ascertained from 10 birth defect surveillance programs; participants who delivered livebirths without a major birth defect ("controls") were randomly selected from birth records or hospital discharge lists. First-trimester antifungal use was self-reported via maternal interview. We estimated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for birth defects with ≥5 exposed cases using logistic regression. We estimated crude ORs and exact 95% CIs for birth defects with 3-4 exposed cases. Additionally, we conducted a probabilistic bias analysis of exposure misclassification. RESULTS: Our analysis included 19 624 cases and 11 427 controls; 257 (1.3%) cases and 123 (1.1%) controls reported first-trimester antifungal use. Of those who reported antifungals, 62.6% of cases and 64.2% of controls reported topical antifungals; 10.1% of cases and 4.9% of controls reported oral antifungals. We observed the strongest associations for encephalocele and Dandy-Walker malformation and modestly elevated estimates for several other defects. Bias-adjusted estimates were similar to the main analysis. CONCLUSION: First-trimester antifungal use was positively associated with several birth defects in our analysis, although CIs were imprecise. Further study is warranted to investigate associations between antifungal use and birth defects, including potential bias due to confounding by indication.

Bias analyses to investigate the impact of differential participation: Application to a birth defects case-control study.

BACKGROUND: Certain associations observed in the National Birth Defects Prevention Study (NBDPS) contrasted with other research or were from areas with mixed findings, including no decrease in odds of spina bifida with periconceptional folic acid supplementation, moderately increased cleft palate odds with ondansetron use and reduced hypospadias odds with maternal smoking. OBJECTIVES: To investigate the plausibility and extent of differential participation to produce effect estimates observed in NBDPS. METHODS: We searched the literature for factors related to these exposures and participation and conducted deterministic quantitative bias analyses. We estimated case-control participation and expected exposure prevalence based on internal and external reports, respectively. For the folic acid-spina bifida and ondansetron-cleft palate analyses, we hypothesized the true odds ratio (OR) based on prior studies and quantified the degree of exposure over- (or under-) representation to produce the crude OR (cOR) in NBDPS. For the smoking-hypospadias analysis, we estimated the extent of selection bias needed to nullify the association as well as the maximum potential harmful OR. RESULTS: Under our assumptions (participation, exposure prevalence, true OR), there was overrepresentation of folic acid use and underrepresentation of ondansetron use and smoking among participants. Folic acid-exposed spina bifida cases would need to have been ≥1.2× more likely to participate than exposed controls to yield the observed null cOR. Ondansetron-exposed cleft palate cases would need to have been 1.6× more likely to participate than exposed controls if the true OR is null. Smoking-exposed hypospadias cases would need to have been ≥1.2 times less likely to participate than exposed controls for the association to falsely appear protective (upper bound of selection bias adjusted smoking-hypospadias OR = 2.02). CONCLUSIONS: Differential participation could partly explain certain associations observed in NBDPS, but questions remain about why. Potential impacts of other systematic errors (e.g. exposure misclassification) could be informed by additional research.

Joint multi-ancestry and admixed GWAS reveals the complex genetics behind human cranial vault shape.

The cranial vault in humans is highly variable, clinically relevant, and heritable, yet its genetic architecture remains poorly understood. Here, we conduct a joint multi-ancestry and admixed multivariate genome-wide association study on 3D cranial vault shape extracted from magnetic resonance images of 6772 children from the ABCD study cohort yielding 30 genome-wide significant loci. Follow-up analyses indicate that these loci overlap with genomic risk loci for sagittal craniosynostosis, show elevated activity cranial neural crest cells, are enriched for processes related to skeletal development, and are shared with the face and brain. We present supporting evidence of regional localization for several of the identified genes based on expression patterns in the cranial vault bones of E15.5 mice. Overall, our study provides a comprehensive overview of the genetics underlying normal-range cranial vault shape and its relevance for understanding modern human craniofacial diversity and the etiology of congenital malformations.

Trends in congenital clubfoot prevalence and co-occurring anomalies during 1994-2021 in Denmark: a nationwide register-based study.

BACKGROUND: Congenital talipes equinovarus (clubfoot) is a common musculoskeletal anomaly, with a suspected multifactorial etiopathogenesis. Herein, we used publicly available data to ascertain liveborn infants with clubfoot delivered in Denmark during 1994-2021, and to classify co-occurring congenital anomalies, estimate annual prevalence, and compare clubfoot occurrence with maternal smoking rates, a commonly reported risk factor. Characterizing this nationwide, liveborn cohort provides a population-based resource for etiopathogenic investigations and life course surveillance. METHODS: This case-cohort study used data from the Danish National Patient Register and Danish Civil Registration System, accessed through the publicly available Danish Biobank Register, to identify 1,315,282 liveborn infants delivered during 1994-2021 in Denmark to Danish parents. Among these, 2,358 infants (65.1% male) were ascertained with clubfoot and classified as syndromic (co-occurring chromosomal, genetic, or teratogenic syndromes) and nonsyndromic (isolated or co-occurring multiple congenital anomalies [MCA]). Annual prevalence estimates and corresponding 95% confidence intervals (CIs) for children with nonsyndromic clubfoot were estimated using Poisson regression and compared with population-based, maternal annual smoking rates obtained from publicly available resources. RESULTS: Infants most often presented with nonsyndromic clubfoot (isolated = 88.6%; MCA = 11.4%); limb and heart anomalies were the most frequently identified MCAs. Prevalence (per 1,000 liveborn infants) was 1.52 (CI 1.45-1.58) for isolated and 0.19 (CI 0.17-0.22) for MCA clubfoot. Prevalence estimates for both isolated and MCA clubfoot remained relatively stable during the study period, despite marked decreases in population-based maternal smoking rates. CONCLUSIONS: From 1994 to 2021, prevalence of nonsyndromic clubfoot in Denmark was relatively stable. Reduction in population-level maternal smoking rates did not seem to impact prevalence estimates, providing some support for the suspected multifactorial etiopathogenesis of this anomaly. This nationwide, liveborn cohort, ascertained and clinically characterized using publicly available data from the Danish Biobank Register, provides a population-based clinical and biological resource for future etiopathogenic investigations and life course surveillance.

Rare variants in CAPN2 increase risk for isolated hypoplastic left heart syndrome.

Hypoplastic left heart syndrome (HLHS) is a severe congenital heart defect (CHD) characterized by hypoplasia of the left ventricle and aorta along with stenosis or atresia of the aortic and mitral valves. HLHS represents only ∼4%-8% of all CHDs but accounts for ∼25% of deaths. HLHS is an isolated defect (i.e., iHLHS) in 70% of families, the vast majority of which are simplex. Despite intense investigation, the genetic basis of iHLHS remains largely unknown. We performed exome sequencing on 331 families with iHLHS aggregated from four independent cohorts. A Mendelian-model-based analysis demonstrated that iHLHS was not due to single, large-effect alleles in genes previously reported to underlie iHLHS or CHD in >90% of families in this cohort. Gene-based association testing identified increased risk for iHLHS associated with variation in CAPN2 (p = 1.8 × 10-5), encoding a protein involved in functional adhesion. Functional validation studies in a vertebrate animal model (Xenopus laevis) confirmed CAPN2 is essential for cardiac ventricle morphogenesis and that in vivo loss of calpain function causes hypoplastic ventricle phenotypes and suggest that human CAPN2707C>T and CAPN21112C>T variants, each found in multiple individuals with iHLHS, are hypomorphic alleles. Collectively, our findings show that iHLHS is typically not a Mendelian condition, demonstrate that CAPN2 variants increase risk of iHLHS, and identify a novel pathway involved in HLHS pathogenesis.

Neighborhood Deprivation and Neural Tube Defects.

BACKGROUND: Individual measures of socioeconomic status (SES) have been associated with an increased risk of neural tube defects (NTDs); however, the association between neighborhood SES and NTD risk is unknown. Using data from the National Birth Defects Prevention Study (NBDPS) from 1997 to 2011, we investigated the association between measures of census tract SES and NTD risk. METHODS: The study population included 10,028 controls and 1829 NTD cases. We linked maternal addresses to census tract SES measures and used these measures to calculate the neighborhood deprivation index. We used generalized estimating equations to calculate adjusted odds ratios (aORs) and 95% confidence intervals (CIs) estimating the impact of quartiles of census tract deprivation on NTDs adjusting for maternal race-ethnicity, maternal education, and maternal age at delivery. RESULTS: Quartiles of higher neighborhood deprivation were associated with NTDs when compared with the least deprived quartile (Q2: aOR = 1.2; 95% CI = 1.0, 1.4; Q3: aOR = 1.3, 95% CI = 1.1, 1.5; Q4 (highest): aOR = 1.2; 95% CI = 1.0, 1.4). Results for spina bifida were similar; however, estimates for anencephaly and encephalocele were attenuated. Associations differed by maternal race-ethnicity. CONCLUSIONS: Our findings suggest that residing in a census tract with more socioeconomic deprivation is associated with an increased risk for NTDs, specifically spina bifida.

Using a health observance event to raise awareness: An assessment of World Birth Defects Day.

World Birth Defects Day (WorldBDDay), observed annually on March 3, was launched in 2015 to advocate for public health surveillance, research, and prevention of birth defects, along with improved care and treatment for affected individuals. Following its fifth observance in 2019, we assessed WorldBDDay by analyzing: (a) engagement and content of over 2000 WorldBDDay posts on Facebook, Twitter, and Instagram; (b) interview responses from 9 WorldBDDay charter (founding) organizations on their perceptions of strengths and areas for improvement for WorldBDDay; (c) survey responses from 61 WorldBDDay 2019 partner (participating) organizations on their WorldBDDay 2019 activities; and (d) post-2019 social media engagement. Most social media posts (60%) occurred from organizations using Twitter (80% vs. 14% for Instagram and 6% for Facebook), although posts from individuals had higher levels of engagement (e.g., likes and comments). The highest engagement occurred for posts focused on general awareness, prevention, or events. Charter organizations reported the need for existing and new partner engagement, including a designated WorldBDDay contact for regular communication and coordination of activities and prepared prevention-focused messaging. Partner organizations reported using the WorldBDDay toolkit, especially key messages and social media tips, and suggested expanding the toolkit with relevant resources. Post-2019 Twitter engagement was lower than 2019 WorldBDDay (peak event) but showed similar reach to WorldBDDay events prior to 2019. Our assessment identified WorldBDDay health observance events as an important tool to support knowledge dissemination and global community engagement around birth defects. Moving forward, engagement with more individuals and organizations may improve the reach of WorldBDDay.

Maternal dietary caffeine consumption and risk of birth defects in the National Birth Defects Prevention Study, 1997-2011.

BACKGROUND: Caffeine consumption is common during pregnancy, but published associations with birth defects are mixed. We updated estimates of associations between prepregnancy caffeine consumption and 48 specific birth defects from the National Birth Defects Prevention Study (NBDPS) for deliveries from 1997 to 2011. METHODS: NBDPS was a large population-based case-control study conducted in 10 U.S. states. We categorized self-reported total dietary caffeine consumption (mg/day) from coffee, tea, soda, and chocolate as: <10, 10 to <100, 100 to <200, 200 to <300, and ≥ 300. We used logistic regression to estimate adjusted odds ratios (aORs [95% confidence intervals]). Analyses for defects with ≥5 exposed case children were adjusted for maternal race/ethnicity, age at delivery, body mass index, early pregnancy cigarette smoking and alcohol use, and study site. RESULTS: Our analysis included 30,285 case and 11,502 control children, with mothers of 52% and 54%, respectively, reporting consuming <100 mg caffeine, and 11% of mothers of both cases and controls reported consuming ≥300 mg per day. Low (10 to <100 mg/day) levels of prepregnancy caffeine consumption were associated with statistically significant increases in aORs (1.2-1.7) for 10 defects. Associations with high (≥300 mg/day) levels of caffeine were generally weaker, except for craniosynostosis and aortic stenosis (aORs = 1.3 [1.1-1.6], 1.6 [1.1-2.3]). CONCLUSIONS: Given the large number of estimates generated, some of the statistically significant results may be due to chance and thus the weakly increased aORs should be interpreted cautiously. This study supports previous observations suggesting lack of evidence for meaningful associations between caffeine consumption and the studied birth defects.

Exome-wide assessment of isolated biliary atresia: A report from the National Birth Defects Prevention Study using child-parent trios and a case-control design to identify novel rare variants.

The etiology of biliary atresia (BA) is unknown, but recent studies suggest a role for rare protein-altering variants (PAVs). Exome sequencing data from the National Birth Defects Prevention Study on 54 child-parent trios, one child-mother duo, and 1513 parents of children with other birth defects were analyzed. Most (91%) cases were isolated BA. We performed (1) a trio-based analysis to identify rare de novo, homozygous, and compound heterozygous PAVs and (2) a case-control analysis using a sequence kernel-based association test to identify genes enriched with rare PAVs. While we replicated previous findings on PKD1L1, our results do not suggest that recurrent de novo PAVs play important roles in BA susceptibility. In fact, our finding in NOTCH2, a disease gene associated with Alagille syndrome, highlights the difficulty in BA diagnosis. Notably, IFRD2 has been implicated in other gastrointestinal conditions and warrants additional study. Overall, our findings strengthen the hypothesis that the etiology of BA is complex.

Influenza vaccination during pregnancy and risk of selected major structural congenital heart defects, National Birth Defects Prevention Study 2006-2011.

BACKGROUND: Although results from studies of first-trimester influenza vaccination and congenital heart defects (CHDs) have been reassuring, data are limited for specific CHDs. METHODS: We assessed associations between reported maternal influenza vaccination, 1 month before pregnancy (B1) through end of third pregnancy month (P3), and specific CHDs using data from a multisite, population-based case-control study. Analysis included 2,982 case children diagnosed with a simple CHD (no other cardiac involvement with or without extracardiac defects) and 4,937 control children without a birth defect with estimated delivery dates during 2006-2011. For defects with ≥5 exposed case children, we used logistic regression to estimate propensity score-adjusted odds ratios (aORs) and 95% confidence intervals (CIs), adjusting for estimated delivery year and season; plurality; and maternal age at delivery, race/ethnicity, low folate intake, and smoking and alcohol use during B1P3. RESULTS: Overall, 124 (4.2%) simple CHD case mothers and 197 (4.0%) control mothers reported influenza vaccination from 1 month before through the third pregnancy month. The aOR for any simple CHD was 0.97 (95% CI: 0.76-1.23). Adjusted ORs for specific simple CHDs ranged from 0.62 for hypoplastic left heart syndrome to 2.34 for total anomalous pulmonary venous return (TAPVR). All adjusted CIs included the null except for TAPVR. CONCLUSIONS: Although we cannot fully exclude that exposure misclassification may have masked risks for some CHDs, findings add to existing evidence supporting the safety of inactivated influenza vaccination during pregnancy. The TAPVR result may be due to chance, but it may help inform future studies.

Prepregnancy exposure to dietary arsenic and congenital heart defects.

INTRODUCTION: Arsenic crosses the placenta and accumulates in fetal tissues. In the United States, diet is the predominant route of arsenic exposure, but epidemiologic data are sparse regarding this exposure and development of birth defects. Using data from a large case-control study, we explored associations between maternal dietary arsenic exposure and congenital heart defects (CHDs), the most prevalent birth defects. METHODS: We used maternal self-reported dietary assessments and arsenic concentration estimates in food items to estimate average daily exposure to dietary arsenic during the year before pregnancy for mothers of 10,446 unaffected control children and 6,483 case children diagnosed with CHDs. Using tertiles of dietary exposure to total arsenic (all species) and inorganic arsenic, we applied logistic regression analysis to estimate associations for middle and high tertiles, compared with the low tertile. RESULTS: Positive associations (odds ratio [OR] ≥ 1.2) for total arsenic were observed in both tertiles for perimembranous ventricular septal defect (VSD) and high tertile only for double outlet right ventricle-transposition of the great arteries (DORV-TGA), partial anomalous pulmonary venous return (PAPVR), and tricuspid atresia. Positive associations were also observed in both tertiles (tricuspid atresia) and high tertile only (DORV-TGA, conoventricular VSD, PAPVR, and pulmonary atresia) for inorganic arsenic. Most remaining associations were near or below unity. DISCUSSION: Exploration of maternal dietary exposure to total and inorganic arsenic and CHDs produced few positive associations but was limited by available food item concentrations. Future research requires expanded collection of dietary data, improved estimates of concentrations, and consideration of nondietary sources of arsenic exposure.

Assessing associations between residential proximity to greenspace and birth defects in the National Birth Defects Prevention Study.

BACKGROUND: Residential proximity to greenspace is associated with various health outcomes. OBJECTIVES: We estimated associations between maternal residential proximity to greenspace (based on an index of vegetation) and selected structural birth defects, including effect modification by neighborhood-level factors. METHODS: Data were from the National Birth Defects Prevention Study (1997-2011) and included 19,065 infants with at least one eligible birth defect (cases) and 8925 without birth defects (controls) from eight Centers throughout the United States. Maternal participants reported their addresses throughout pregnancy. Each address was systematically geocoded and residences around conception were linked to greenspace, US Census, and US Department of Agriculture data. Greenspace was estimated using the normalized difference vegetation index (NDVI); average maximum NDVI was estimated within 100 m and 500 m concentric buffers surrounding geocoded addresses to estimate residential NDVI. We used logistic regression to estimate odds ratios (ORs) and 95% confidence intervals comparing those in the highest and lowest quartiles of residential NDVI and stratifying by rural/urban residence and neighborhood median income. RESULTS: After multivariable adjustment, for the 500 m buffer, inverse associations were observed for tetralogy of Fallot, secundum atrial septal defects, anencephaly, anotia/microtia, cleft lip ± cleft palate, transverse limb deficiency, and omphalocele, (aORs: 0.54-0.86). Results were similar for 100 m buffer analyses and similar patterns were observed for other defects, though results were not significant. Significant heterogeneity was observed after stratification by rural/urban for hypoplastic left heart, coarctation of the aorta, and cleft palate, with inverse associations only among participants residing in rural areas. Stratification by median income showed heterogeneity for atrioventricular and secundum atrial septal defects, anencephaly, and anorectal atresia, with inverse associations only among participants residing in a high-income neighborhood (aORs: 0.45-0.81). DISCUSSION: Our results suggest that perinatal residential proximity to more greenspace may contribute to a reduced risk of certain birth defects, especially among those living in rural or high-income neighborhoods.