Prevalence and descriptive epidemiology of choanal atresia and stenosis in Texas, 1999-2018.

Choanal atresia and stenosis are common causes of congenital nasal obstruction, but their epidemiology is poorly understood. Compared to bilateral choanal atresia/stenosis, unilateral choanal atresia/stenosis is generally diagnosed later and might be under-ascertained in birth defect registries. Data from the population-based Texas Birth Defects Registry and Texas vital records, 1999-2018, were used to assess the prevalence of choanal atresia/stenosis. Poisson regression models were used to evaluate associations with infant and maternal characteristics in two analytic groups: isolated choanal atresia/stenosis (n = 286) and isolated, bilateral choanal atresia/stenosis (n = 105). The overall prevalence of choanal atresia/stenosis was 0.92/10,000, and the prevalence of isolated choanal atresia/stenosis was 0.37/10,000 livebirths. Variables associated with choanal atresia/stenosis in one or both analytic groups included infant sex, pregnancy plurality, maternal race/ethnicity, maternal age, and maternal residence on the Texas-Mexico border. In general, adjusted prevalence ratios estimated from the two analytic groups were in the same direction but tended to be stronger in the analyses restricted to isolated, bilateral defects. Epidemiologic studies of isolated choanal atresia/stenosis should consider focusing on cases with bilateral defects, and prioritizing analyses of environmental, social, and structural factors that could account for the association with maternal residence on the Texas-Mexico border.

Classification of isolated versus multiple birth defects: An automated process for population-based registries.

Epidemiologic studies of birth defects often conduct separate analyses for cases that have isolated defects (e.g., spina bifida only) and cases that have multiple defects (e.g., spina bifida and a congenital heart defect). However, in some instances, cases with additional defects (e.g., spina bifida and clubfoot) may be more appropriately considered as isolated because the co-occurring defect (clubfoot) is believed to be developmentally related to the defect of interest. Determining which combinations should be considered isolated can be challenging and potentially resource intensive for registries. Thus, we developed automated classification procedures for differentiating between isolated versus multiple defects, while accounting for developmentally related defects, and applied the approach to data from the Texas Birth Defects Registry (1999-2018 deliveries). Among 235,544 nonsyndromic cases in Texas, 89% of cases were classified as having isolated defects, with proportions ranging from 25% to 92% across 43 specific defects analyzed. A large proportion of isolated cases with spina bifida (44%), lower limb reduction defects (44%), and holoprosencephaly (32%) had developmentally related defects. Overall, our findings strongly support the need to account for isolated versus multiple defects in risk factor association analyses and to account for developmentally related defects when doing so, which has implications for interpreting prior studies.

Common Genetic Variants Contribute to Risk of Transposition of the Great Arteries.

RATIONALE: Dextro-transposition of the great arteries (D-TGA) is a severe congenital heart defect which affects approximately 1 in 4,000 live births. While there are several reports of D-TGA patients with rare variants in individual genes, the majority of D-TGA cases remain genetically elusive. Familial recurrence patterns and the observation that most cases with D-TGA are sporadic suggest a polygenic inheritance for the disorder, yet this remains unexplored. OBJECTIVE: We sought to study the role of common single nucleotide polymorphisms (SNPs) in risk for D-TGA. METHODS AND RESULTS: We conducted a genome-wide association study in an international set of 1,237 patients with D-TGA and identified a genome-wide significant susceptibility locus on chromosome 3p14.3, which was subsequently replicated in an independent case-control set (rs56219800, meta-analysis P=8.6x10-10, OR=0.69 per C allele). SNP-based heritability analysis showed that 25% of variance in susceptibility to D-TGA may be explained by common variants. A genome-wide polygenic risk score derived from the discovery set was significantly associated to D-TGA in the replication set (P=4x10-5). The genome-wide significant locus (3p14.3) co-localizes with a putative regulatory element that interacts with the promoter of WNT5A, which encodes the Wnt Family Member 5A protein known for its role in cardiac development in mice. We show that this element drives reporter gene activity in the developing heart of mice and zebrafish and is bound by the developmental transcription factor TBX20. We further demonstrate that TBX20 attenuates Wnt5a expression levels in the developing mouse heart. CONCLUSIONS: This work provides support for a polygenic architecture in D-TGA and identifies a susceptibility locus on chromosome 3p14.3 near WNT5A. Genomic and functional data support a causal role of WNT5A at the locus.

Congenital Heart Defects and Concurrent Diagnoses in Influenza Hospitalization in the Pediatric Health Information System Study, 2004-2019.

Influenza is associated with adverse outcomes in children, although modification by additional medical conditions is not well-documented. We aimed to compare outcomes in children with versus without congenital heart defects (CHDs) who were hospitalized for influenza. We retrospectively evaluated patients 1-18y hospitalized for influenza in the Pediatric Health Information (PHIS) database from 2004 to 2019. Outcomes were compared by CHD presence and then by CHD severity (minor biventricular, major biventricular, and single ventricle disease) using log-binomial regression adjusted for propensity scores accounting for age at admission, sex, and history of asthma. Outcomes included inpatient mortality, intensive care unit (ICU) admission, mechanical ventilation, and length of stay (LOS) > 12 days. To evaluate for effect modification by genetic diagnoses, analyses were repeated stratified by CHD and genetic diagnosis. Among 55,161 children hospitalized for influenza, 2369 (4.3%) had CHDs, including 963 with minor biventricular, 938 with major biventricular, and 468 with single ventricle CHDs. Adjusting for propensity scores, children with CHDs had higher mortality (4.1% versus 0.9%) compared to those without CHDs (risk ratio [RR] 2.5, 95% confidence interval [CI] 1.9-3.4). Children with CHDs were at higher risk of mechanical ventilation (RR 1.6, 95% CI 1.6-1.7), ICU admission (RR 1.9, 95% CI 1.8-2.1), and LOS > 12 days (RR 2.2, 95% CI 2.0-2.3). Compared to those with neither CHD nor genetic condition, children with both had significantly higher risk of all outcomes, with the largest difference for LOS > 12 days (RR 2.3, 95% CI 2.0-2.7). Children with CHDs hospitalized for influenza are particularly susceptible to adverse outcomes compared to those without CHDs. Future studies are needed to corroborate findings in light of influenza vaccination.

Complete Sequence of the 22q11.2 Allele in 1,053 Subjects with 22q11.2 Deletion Syndrome Reveals Modifiers of Conotruncal Heart Defects.

The 22q11.2 deletion syndrome (22q11.2DS) results from non-allelic homologous recombination between low-copy repeats termed LCR22. About 60%-70% of individuals with the typical 3 megabase (Mb) deletion from LCR22A-D have congenital heart disease, mostly of the conotruncal type (CTD), whereas others have normal cardiac anatomy. In this study, we tested whether variants in the hemizygous LCR22A-D region are associated with risk for CTDs on the basis of the sequence of the 22q11.2 region from 1,053 22q11.2DS individuals. We found a significant association (FDR p < 0.05) of the CTD subset with 62 common variants in a single linkage disequilibrium (LD) block in a 350 kb interval harboring CRKL. A total of 45 of the 62 variants were associated with increased risk for CTDs (odds ratio [OR) ranges: 1.64-4.75). Associations of four variants were replicated in a meta-analysis of three genome-wide association studies of CTDs in affected individuals without 22q11.2DS. One of the replicated variants, rs178252, is located in an open chromatin region and resides in the double-elite enhancer, GH22J020947, that is predicted to regulate CRKL (CRK-like proto-oncogene, cytoplasmic adaptor) expression. Approximately 23% of patients with nested LCR22C-D deletions have CTDs, and inactivation of Crkl in mice causes CTDs, thus implicating this gene as a modifier. Rs178252 and rs6004160 are expression quantitative trait loci (eQTLs) of CRKL. Furthermore, set-based tests identified an enhancer that is predicted to target CRKL and is significantly associated with CTD risk (GH22J020946, sequence kernal association test (SKAT) p = 7.21 × 10-5) in the 22q11.2DS cohort. These findings suggest that variance in CTD penetrance in the 22q11.2DS population can be explained in part by variants affecting CRKL expression.

Contribution of Preterm Birth to Mortality Among Neonates with Birth Defects.

OBJECTIVE: To estimate the proportion of neonatal mortality risk attributable to preterm delivery among neonates with birth defects. STUDY DESIGN: Using a statewide cohort of live born infants from the Texas Birth Defects Registry (1999-2014 deliveries), we estimated the population attributable fraction and 95% CI of neonatal mortality (death <28 days) attributable to prematurity (birth at <37 weeks vs ≥37 weeks) for 31 specific birth defects. To better understand the overall population burden, analyses were repeated for all birth defects combined. RESULTS: Our analyses included 169 148 neonates with birth defects, of which 40 872 (24.2%) were delivered preterm. The estimated proportion of neonatal mortality attributable to prematurity varied by birth defect, ranging from 12.5% (95% CI: 8.7-16.1) for hypoplastic left heart syndrome to 71.9% (95% CI: 41.1-86.6) for anotia or microtia. Overall, the proportion was 51.7% (95% CI: 49.4-54.0) for all birth defects combined. CONCLUSIONS: A large proportion of deaths among neonates with birth defects are attributable to preterm delivery. Our results highlight differences in this burden across common birth defects. Our findings may be helpful for prioritizing future work focused on better understanding the etiology of prematurity among neonates with birth defects and the mechanisms by which prematurity contributes to neonatal mortality in this population.

Identifying syndromes in studies of structural birth defects: Guidance on classification and evaluation of potential impact.

Structural birth defects that occur in infants with syndromes may be etiologically distinct from those that occur in infants in whom there is not a recognized pattern of malformations; however, population-based registries often lack the resources to classify syndromic status via case reviews. We developed criteria to systematically identify infants with suspected syndromes, grouped by syndrome type and level of effort required for syndrome classification (e.g., text search). We applied this algorithm to the Texas Birth Defects Registry (TBDR) to describe the proportion of infants with syndromes delivered during 1999-2014. We also developed a bias analysis tool to estimate the potential percent bias resulting from including infants with syndromes in studies of risk factors. Among 207,880 cases with birth defects in the TBDR, 15% had suspected syndromes and 85% were assumed to be nonsyndromic, with a range across defect types from 28.5% (atrioventricular septal defects) to 98.9% (pyloric stenosis). Across hypothetical scenarios varying expected parameters (e.g., nonsyndromic proportion), the inclusion of syndromic cases in analyses resulted in up to 50.0% bias in prevalence ratios. In summary, we present a framework for identifying infants with syndromic conditions; implementation might harmonize syndromic classification across registries and reduce bias in association estimates.

Patterns of co-occurring birth defects in children with anotia and microtia.

Many infants with anotia or microtia (A/M) have co-occurring birth defects, although few receive syndromic diagnoses in the perinatal period. Evaluation of co-occurring birth defects in children with A/M could identify patterns indicative of undiagnosed/unrecognized syndromes. We obtained information on co-occurring birth defects among infants with A/M for delivery years 1999-2014 from the Texas Birth Defects Registry. We calculated observed-to-expected ratios (OER) to identify birth defect combinations that occurred more often than expected by chance. We excluded children diagnosed with genetic or chromosomal syndromes from analyses. Birth defects and syndromes/associations diagnosed ≤1 year of age were considered. We identified 1310 infants with non-syndromic A/M, of whom 38% (N = 492) were diagnosed with co-occurring major defects. Top combinations included: hydrocephalus, ventricular septal defect, and spinal anomalies (OER 58.4); microphthalmia and anomalies of the aorta (OER 55.4); and cleft lip with or without cleft palate and rib or sternum anomalies (OER 32.8). Some combinations observed in our study may represent undiagnosed/atypical presentations of known A/M associations or syndromes, or novel syndromes yet to be described in the literature. Careful evaluation of infants with multiple birth defects including A/M is warranted to identify individuals with potential genetic or chromosomal syndromes.

Prevalence and descriptive epidemiology of Turner syndrome in the United States, 2000-2017: A report from the National Birth Defects Prevention Network.

The lack of United States population-based data on Turner syndrome limits assessments of prevalence and associated characteristics for this sex chromosome abnormality. Therefore, we collated 2000-2017 data from seven birth defects surveillance programs within the National Birth Defects Prevention Network. We estimated the prevalence of karyotype-confirmed Turner syndrome diagnosed within the first year of life. We also calculated the proportion of cases with commonly ascertained birth defects, assessed associations with maternal and infant characteristics using prevalence ratios (PR) with 95% confidence intervals (CI), and estimated survival probability. The prevalence of Turner syndrome of any pregnancy outcome was 3.2 per 10,000 female live births (95% CI = 3.0-3.3, program range: 1.0-10.4), and 1.9 for live birth and stillbirth (≥20 weeks gestation) cases (95% CI = 1.8-2.1, program range: 0.2-3.9). Prevalence was lowest among cases born to non-Hispanic Black women compared to non-Hispanic White women (PR = 0.5, 95% CI = 0.4-0.6). Coarctation of the aorta was the most common defect (11.6% of cases), and across the cohort, individuals without hypoplastic left heart had a five-year survival probability of 94.6%. The findings from this population-based study may inform surveillance practices, prenatal counseling, and diagnosis. We also identified racial and ethnic disparities in prevalence, an observation that warrants further investigation.

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.

Prediction of Preterm Birth among Infants with Orofacial Cleft Defects.

OBJECTIVE: To develop risk prediction models for preterm birth among infants with orofacial clefts. DESIGN: Data from the Texas Birth Defects Registry for infants with orofacial clefts born between 1999-2014 were used to develop preterm birth predictive models. Logistic regression was used to consider maternal and infant characteristics, and internal validation of the final model was performed using bootstrapping methods. The area under the curve (AUC) statistic was generated to assess model performance, and separate predictive models were built and validated for infants with cleft lip and cleft palate alone. Several secondary analyses were conducted among subgroups of interest. SETTING: State-wide, population-based Registry data. PATIENTS/PARTICIPANTS: 6774 infants with orofacial clefts born in Texas between 1999-2014. MAIN OUTCOME MEASURE(S): Preterm birth among infants with orofacial clefts. RESULTS: The final predictive model performed modestly, with an optimism-corrected AUC of 0.67 among all infants with orofacial clefts. The optimism-corrected models for cleft lip (with or without cleft palate) and cleft palate alone had similar predictive capability, with AUCs of 0.66 and 0.67, respectively. Secondary analyses had similar results, but the model among infants with delivery prior to 32 weeks demonstrated higher optimism-corrected predictive capability (AUC = 0.74). CONCLUSIONS: This study provides a first step towards predicting preterm birth risk among infants with orofacial clefts. Identifying pregnancies affected by orofacial clefts at the highest risk for preterm birth may lead to new avenues for improving outcomes among these infants.

Epidemiology of Nonsyndromic, Orofacial Clefts in Texas: Differences by Cleft Type and Presence of Additional Defects.

To describe the current epidemiology of nonsyndromic cleft palate alone (CP) and cleft lip with or without cleft palate (CL ± P) in Texas and examine differences in the characteristics of infants with CP and CL ± P based on the presence/absence of additional defects.We used data from the Texas Birth Defects Registry, a statewide active birth defect surveillance system, from 1815 cases with CP and 5066 with CL ± P, without a syndrome diagnosis (1999-2014 deliveries). All live births in Texas were used for comparison. Poisson regression was used to calculate crude and adjusted prevalence ratios (aPR) for each characteristic, separately for each cleft subphenotype.The prevalence of CL ± P and CP in our study was estimated as 8.3 and 3.0 per 10 000 live births, respectively. After adjusting for several characteristics, several factors were associated with CL ± P, CP, or both, including infant sex and maternal race/ethnicity, age, smoking, and diabetes. There were several differences between infants with isolated versus nonisolated clefts. For example, maternal prepregnancy diabetes was associated with an increased prevalence of CL ± P (aPR 7.91, 95% confidence interval [CI]: 5.53, 11.30) and CP (aPR 3.24, 95% CI: 1.43, 7.36), but only when additional defects were present.Findings from this study provide a contemporary description of the distribution of orofacial clefts in Texas accounting for differences between isolated and nonisolated clefts. They may contribute to increasing our understanding of the etiology of CP and CL ± P.

The Epidemiology of Biliary Atresia: Exploring the Role of Developmental Factors on Birth Prevalence.

OBJECTIVE: To identify key epidemiologic factors relevant to fetal development that are associated with biliary atresia. STUDY DESIGN: This population-based registry study examined infants born in Texas between 1999 and 2014. Epidemiologic data relevant to fetal development were compared between cases of biliary atresia identified in the Texas Birth Defects Registry (n = 305) vs all live births (n = 4 689 920), and Poisson regression was used to calculate prevalence ratios (PRs) and 95% CIs. RESULTS: The prevalence of biliary atresia over the study period was 0.65 per 10 000 live births. Biliary atresia was positively associated with female sex (adjusted PR, 1.68; 95% CI, 1.33-2.12), delivery before 32-37 weeks of gestation (adjusted PR, 1.64; 95% CI, 1.18-2.29), delivery before 32 weeks of gestation (adjusted PR, 3.85; 95% CI, 2.38-6.22), and non-Hispanic Black vs non-Hispanic White maternal race/ethnicity (adjusted PR, 1.54, 95% CI, 1.06-2.24), while biliary atresia was inversely associated with season of conception in the fall relative to spring (adjusted PR, 0.62; 95% CI, 0.45-0.86). In addition, biliary atresia was associated with maternal diabetes (adjusted PR, 2.34; 95% CI, 1.57-3.48), with a stronger association with pregestational diabetes compared with gestational diabetes. In subgroup analyses, these associations were present in isolated biliary atresia cases that do not have any additional birth defects. CONCLUSIONS: Biliary atresia is associated with multiple factors related to fetal development, including pregestational maternal diabetes, female sex, and preterm birth. These associations also were observed in isolated cases of biliary atresia without other malformations or laterality defects. Our results are consistent with early life events influencing the pathogenesis of biliary atresia, and support further studies investigating in utero events to better understand etiology and time of onset.

Birth defect co-occurrence patterns in the Texas Birth Defects Registry.

BACKGROUND: The population-level landscape of co-occurring birth defects among infants without a syndromic diagnosis is not well understood. METHODS: We analyzed data from 40,771 infants with two or more major birth defects in the Texas Birth Defects Registry (TBDR; 1999-2014). We calculated adjusted observed-to-expected (O/E) ratios for all two, three, four, and five-way combinations of 138 major defects. RESULTS: Among 530 patterns with the highest adjusted O/E ratios (top 5% of 10,595 patterns), 66% included only defects co-occurring within one organ system and 28% were suggestive of known patterns (e.g., midline developmental defects). Of the remaining patterns, the combination of defects with the highest O/E ratio (193.8) encompassed the diaphragm, spine, spleen, and heart defects. Fourteen patterns involved heart and spine defects with or without rib defects. Ten additional patterns primarily involved two hallmark components of VACTERL association (specifically, vertebral defects, anal atresia, cardiac defects, renal, or limb defects, but not tracheoesophageal fistula). CONCLUSIONS: Our analyses provide a description of the birth defect co-occurrence patterns in a multi-ethnic, population-based sample, and revealed several patterns of interest. This work complements prior work that has suggested etiologic connections between select defects (e.g., diaphragmatic hernia and heart and spleen anomalies; heart and spine defects). IMPACT: In this large-scale, population-based study of birth defect co-occurrence patterns, we found several birth defect combinations of potential interest that warrant further investigation: congenital diaphragmatic hernia, heart, spine, and spleen defects and scimitar syndrome with vertebral defects. The majority of patterns of co-occurring defects observed more frequently than expected involved multiple defects within the same system and combinations suggestive of known associations. Nearly all of the top patterns (beyond the same system and those suggestive of known associations) involved organ systems that are components of the VACTERL association, with heart, spine, and rib defect patterns being the most common.

Birth Defect Co-Occurrence Patterns Among Infants With Cleft Lip and/or Palate.

OBJECTIVE: To investigate 2- to 5-way patterns of defects co-occurring with orofacial clefts using data from a population-based registry. DESIGN: We used data from the Texas Birth Defects Registry for deliveries between 1999 and 2014 to Texas residents, including 1884 cases with cleft palate (CP) and 5289 cases with cleft lip with or without cleft palate (CL±P) without a known syndrome. We identified patterns of defects co-occurring with CP and with CL±P observed more frequently than would be expected if these defects occurred independently. We calculated adjusted observed-to-expected (O/E) ratios to account for the known tendency of birth defects to cluster nonspecifically. RESULTS: Among infants without a syndrome, 23% with CP and 21% with CL±P had at least 1 additional congenital anomaly. Several combinations of defects were observed much more often than expected. For example, the combination of CL±P, congenital hydrocephaly, anophthalmia, and other nose anomalies had an O/E ratio of 605. For both CP and CL±P, co-occurrence patterns with the highest O/E ratios involved craniofacial and brain abnormalities, and many included the skeletal, cardiovascular, and renal systems. CONCLUSIONS: The patterns of defects we observed co-occurring with clefts more often than expected may help improve our understanding of the relationships between multiple defects. Further work to better understand some of the top defect combinations could reveal new phenotypic subgroups and increase our knowledge of the developmental mechanisms that underlie the respective defects.

The TFAP2A-IRF6-GRHL3 genetic pathway is conserved in neurulation.

Mutations in IRF6, TFAP2A and GRHL3 cause orofacial clefting syndromes in humans. However, Tfap2a and Grhl3 are also required for neurulation in mice. Here, we found that homeostasis of Irf6 is also required for development of the neural tube and associated structures. Over-expression of Irf6 caused exencephaly, a rostral neural tube defect, through suppression of Tfap2a and Grhl3 expression. Conversely, loss of Irf6 function caused a curly tail and coincided with a reduction of Tfap2a and Grhl3 expression in tail tissues. To test whether Irf6 function in neurulation was conserved, we sequenced samples obtained from human cases of spina bifida and anencephaly. We found two likely disease-causing variants in two samples from patients with spina bifida. Overall, these data suggest that the Tfap2a-Irf6-Grhl3 genetic pathway is shared by two embryologically distinct morphogenetic events that previously were considered independent during mammalian development. In addition, these data suggest new candidates to delineate the genetic architecture of neural tube defects and new therapeutic targets to prevent this common birth defect.

Patterns of congenital anomalies among individuals with trisomy 13 in Texas.

Few population-based studies have analyzed patterns of co-occurring birth defects among those with trisomy 13. We evaluated the frequency of all possible combinations of any one, two, three, or four additional co-occurring birth defects among 736 individuals with trisomy 13 using data from the Texas Birth Defects Registry for deliveries during 1999-2014. We calculated the observed-to-expected ratio for each combination, adjusting for the known tendency for birth defects to cluster non-specifically. To address potential ascertainment differences among live births and non-live births, we repeated analyses specifically among live births. The combination of defects with the largest observed-to-expected ratio was microcephalus, reduction deformities of brain (e.g., holoprosencephaly), anomalies of nose, and polydactyly. As expected, most of the highest 30 observed-to-expected ratios involved combinations with documented features of trisomy 13, including defects of the scalp (e.g., aplasia cutis) and heart. Results were similar among sensitivity analyses restricted to live births. Our findings may help further delineate the phenotypic spectrum for trisomy 13 and may inform future research related to improving screening and counseling for the condition.

Birth defects that co-occur with non-syndromic gastroschisis and omphalocele.

Gastroschisis and omphalocele are the two most common abdominal wall birth defects, and epidemiologic characteristics and frequency of occurrence as part of a syndromic condition suggest distinct etiologies between the two defects. We assessed complex patterns of defect co-occurrence with these defects separately using the Texas Birth Defects Registry. We used co-occurring defect analysis (CODA) to compute adjusted observed-to-expected (O/E) ratios for all observed birth defect patterns. There were 2,998 non-syndromic (i.e., no documented syndrome diagnosis identified) cases with gastroschisis and 789 (26%) of these had additional co-occurring defects. There were 720 non-syndromic cases with omphalocele, and 404 (56%) had additional co-occurring defects. Among the top 30 adjusted O/E ratios for gastroschisis, most of the co-occurring defects were related to the gastrointestinal system, though cardiovascular and kidney anomalies were also present. Several of the top 30 combinations co-occurring with omphalocele appeared suggestive of OEIS (omphalocele, exstrophy of cloaca, imperforate anus, spinal defects) complex. After the exclusion of additional cases with features suggestive of OEIS in a post-hoc sensitivity analysis, the top combinations involving defects associated with OEIS (e.g., spina bifida) were no longer present. The remaining top combinations involving omphalocele included cardiovascular, gastrointestinal, and urogenital defects. In summary, we identified complex patterns of defects that co-occurred more frequently than expected with gastroschisis and omphalocele using a novel software platform. Better understanding differences in the patterns between gastroschisis and omphalocele could lead to additional etiologic insights.

Differences in pre-pregnancy diet quality by occupation among employed women.

OBJECTIVE: Maternal risk factors for pregnancy outcomes are known to vary by employment status. We evaluated whether pre-pregnancy diet quality varies by occupation in a population-based sample. DESIGN: We analysed interview data from 7341 mothers in a national case-control study of pregnancy outcomes. Self-reported job(s) held during the 3 months before pregnancy were classified using Standard Occupational Classification (SOC) codes. Usual diet in the year before conception was assessed with a semi-quantitative FFQ and evaluated using the Diet Quality Index for Pregnancy (DQI-P). Using logistic regression, we calculated adjusted OR and 95 % CI to estimate associations between low diet quality (defined as the lowest quartile of DQI-P scores) and occupation types. SETTING: The National Birth Defects Prevention Study: Arkansas, California, Georgia, Iowa, Massachusetts, North Carolina, New Jersey, New York, Texas, Utah. PARTICIPANTS: Employed mothers of infants born between 1997 and 2011. RESULTS: No occupation was strongly associated with low diet quality. Moderate but relatively imprecise associations were observed for women employed in management (OR: 1·3; 95 % CI: 1·1, 1·7); arts, design, entertainment, sports and media (OR: 1·4; 95 % CI: 0·9, 2·1); protective service (OR 1·3; 95 % CI: 0·7, 2·5) and farming, fishing, and forestry occupations (OR: 0·5; 95 % CI: 0·2, 1·1). CONCLUSIONS: Our analyses suggest that women in certain occupations may have lower diet quality in the months before pregnancy. Further research is needed to determine whether certain occupations could benefit from interventions to improve diet quality in the workplace for women of reproductive age.

Maternal Lactase Polymorphism (rs4988235) Is Associated with Neural Tube Defects in Offspring in the National Birth Defects Prevention Study.

BACKGROUND: The risk of neural tube defect (NTD)-affected pregnancies is reduced with adequate folic acid intake during early pregnancy. However, NTDs have been observed among offspring of women with adequate folic acid intake. Some of these women are possibly not absorbing enough folic acid. Because lactase deficiency can lead to poor nutrient absorption, we hypothesized that lactase-deficient women will be at increased risk of having offspring with NTDs. OBJECTIVE: We examined the association between maternal rs4988235 (a lactase deficiency genetic marker) and NTDs in offspring. METHODS: We conducted a case-control study using data from the National Birth Defects Prevention Study, United States, 1997-2009, restricting to non-Hispanic white (NHW) and Hispanic women. Cases were women with an offspring with an NTD (n = 378 NHW, 207 Hispanic), and controls were women with an offspring without a birth defect (n = 461 NHW, 165 Hispanic). Analyses were conducted separately by race/ethnicity, using logistic regression. Women with the CC genotype were categorized as being lactase deficient. To assess potential effect modification, analyses were stratified by lactose intake, folic acid supplementation, dietary folate, and diet quality. RESULTS: Among NHW women, the odds of being lactase deficient were greater among cases compared with controls (OR: 1.37; 95% CI: 1.02, 1.82). Among Hispanic women, the odds of being lactase deficient were significantly lower among cases compared with controls (OR: 0.50, 95% CI: 0.33, 0.77). The association differed when stratified by lactose intake in NHW women (higher odds among women who consumed ≥12 g lactose/1000 kcal) and by dietary folate in Hispanic women (opposite direction of associations). The association did not differ when stratified by folic acid supplementation or diet quality. CONCLUSIONS: Our findings suggest that maternal lactase deficiency is associated with NTDs in offspring. However, we observed opposite directions of effect by race/ethnicity that could not be definitively explained.