From cause to care: Triple surveillance for better outcomes in birth defects and rare diseases

Better outcomes are a priority for all those who care about birth defects and rare diseases. Public health surveillance and epidemiologic data tracking historically have provided good data on disease occurrence but at most uncertain value in promoting better outcomes, be these in terms of supporting primary prevention or better care. We propose three enhancements to improve the value of surveillance. First, merge: eliminate the largely artificial separation between birth defects and rare diseases in surveillance. Second, expand the scope of surveillance to 'triple surveillance': include in surveillance the three components of the causal chain from primary cause (e.g., folic acid insufficiency) to disease occurrence (e.g., spina bifida prevalence) and further to health outcomes (e.g., mortality, morbidity). Third, integrate public health with clinical surveillance: streamline data collection (avoid 'recreational data collection') and use the data rapidly not only for epidemiologic assessment but also for evaluation and improvement of clinical care. Many countries have one or more of the elements of this framework already in place. Typically, however, they are not integrated, and work and data get wasted. Fundamentally, these enhancements require rethinking priorities, partnerships and data sharing policies. By reducing waste (e.g., activities leading to data being collected but not used) they will add value and probably decrease costs. Importantly, such systems can help make visible the health issues of a population and the benefits (or lack thereof) of interventions, and support quality improvement in prevention and delivery of care.

Development and Utility of a Birth Defects Surveillance Toolkit

According to the World Health Organization (WHO), an estimated 303,000 neonates die within their first month of age every year globally as a result of a birth defect. Neural tube defects, serious birth defects of the brain and spine, are among the most common and severe of these birth defects. Since some low- and middle-income countries lack comprehensive, accurate data documenting the burden of these defects, providing technical assistance to help build birth defects surveillance programs can accelerate the collection of data needed to demonstrate this burden and advance prevention initiatives. We developed a birth defects surveillance toolkit, a technical assistance tool for country staff to help them implement birth defects surveillance. An evaluation of the toolkit with partners in Africa was conducted to assess perceptions of the usefulness, effectiveness, and policy impact of the surveillance toolkit and surveillance-related technical assistance provided to countries thus far. Overall, respondents provided very positive feedback about the toolkit components. Recommendations for improvement included customization to country contexts, such as photos reflective of African babies; surveillance examples from other countries; and consistent use of terms.

Case Definitions for Conditions Identified by Newborn Screening Public Health Surveillance

Newborn screening (NBS) identifies infants with rare conditions to prevent death or the onset of irreversible morbidities. Conditions on the Health and Human Services Secretary's Recommended Uniform Screening Panel have been adopted by most state NBS programs, providing a consistent approach for identification of affected newborns across the United States. Screen-positive newborns are identified and referred for confirmatory diagnosis and follow-up. The designation of a clinically significant phenotype precursor to a clinical diagnosis may vary between clinical specialists, resulting in diagnostic variation. Determination of disease burden and birth prevalence of the screened conditions by public health tracking is made challenging by these variations. This report describes the development of a core group of new case definitions, along with implications, plans for their use, and links to the definitions that were developed by panels of clinical experts. These definitions have been developed through an iterative process and are piloted in NBS programs. Consensus public health surveillance case definitions for newborn screened disorders will allow for consistent categorization and tracking of short- and long-term follow-up of identified newborns at the local, regional, and national levels.

Epidemiology and Prognosis of Congenital Diaphragmatic Hernia: A Population-Based Cohort Study in Utah

BACKGROUND

Congenital diaphragmatic hernia (CDH) is a relatively frequent and severe malformation. Population-based data on clinical presentation and associated mortality are scarce. We examined a state-wide cohort of infants with a clinically validated diagnosis of CDH to assess their clinical profile, sociodemographic patterns, and infant mortality.

METHODS

We identified CDH cases from Utah's statewide population-based surveillance program among the cohort of all pregnancy outcomes (live births, stillbirths, and pregnancy terminations) delivered from 1999 to 2011. Clinical geneticists reviewed all cases and classified them based on etiology (known, unknown), and whether they were isolated, multiple (additional unrelated major malformations or unique minor malformation), or syndromic (genetic, chromosomal).

RESULTS

CDH occurred in 1 in 3156 births (227/718,990, or 3.17 per 10,000), with no time trend during the 13 years (p = 0.85). CDH was much more common in males (male to female ratio, 1.72:1; p < 0.01). Clinically, 64% of the cases were isolated, 23% were multiples, and 13% were syndromic. Most cases were live born (90%), with fewer stillbirths (7%) and pregnancy terminations (3%). Overall infant mortality was 32.5%, and varied considerably by underlying etiology (isolated 21%; multiple 44%; syndromic 82%). Prognosis was related to specific clinical findings within each etiologic group (e.g., prematurity, low Apgar score, and intrathoracic liver).

CONCLUSION

This information on specific clinical and etiologic factors associated with prognosis can help clinicians and parents in the complex discussions about care planning and management that often occur in a crisis situation, following the diagnosis of CDH, whether prior or after delivery. Birth Defects Research 109:1451-1459, 2017.© 2017 Wiley Periodicals, Inc.

Maternal Exposure to Nitrogen Dioxide, Intake of Methyl Nutrients, and Congenital Heart Defects in Offspring

Nutrients that regulate methylation processes may modify susceptibility to the effects of air pollutants. Data from the National Birth Defects Prevention Study (United States, 1997-2006) were used to estimate associations between maternal exposure to nitrogen dioxide (NO2), dietary intake of methyl nutrients, and the odds of congenital heart defects in offspring. NO2 concentrations, a marker of traffic-related air pollution, averaged across postconception weeks 2-8, were assigned to 6,160 nondiabetic mothers of cases and controls using inverse distance-squared weighting of air monitors within 50 km of maternal residences. Intakes of choline, folate, methionine, and vitamins B6 and B12 were assessed using a food frequency questionnaire. Hierarchical regression models, which accounted for similarities across defects, were constructed, and relative excess risks due to interaction were calculated. Relative to women with the lowest NO2 exposure and high methionine intake, women with the highest NO2 exposure and lowest methionine intake had the greatest odds of offspring with a perimembranous ventricular septal defect (odds ratio = 3.23, 95% confidence interval: 1.74, 6.01; relative excess risk due to interaction = 2.15, 95% confidence interval: 0.39, 3.92). Considerable departure from additivity was not observed for other defects. These results provide modest evidence of interaction between nutrition and NO2 exposure during pregnancy.

Etiology and clinical presentation of birth defects: population based study

Objective To assess causation and clinical presentation of major birth defects.Design Population based case cohort.Setting Cases of birth defects in children born 2005-09 to resident women, ascertained through Utah's population based surveillance system. All records underwent clinical re-review.Participants 5504 cases among 270 878 births (prevalence 2.03%), excluding mild isolated conditions (such as muscular ventricular septal defects, distal hypospadias).Main outcome measures The primary outcomes were the proportion of birth defects with a known etiology (chromosomal, genetic, human teratogen, twinning) or unknown etiology, by morphology (isolated, multiple, minors only), and by pathogenesis (sequence, developmental field defect, or known pattern of birth defects).Results Definite cause was assigned in 20.2% (n=1114) of cases: chromosomal or genetic conditions accounted for 94.4% (n=1052), teratogens for 4.1% (n=46, mostly poorly controlled pregestational diabetes), and twinning for 1.4% (n=16, conjoined or acardiac). The 79.8% (n=4390) remaining were classified as unknown etiology; of these 88.2% (n=3874) were isolated birth defects. Family history (similarly affected first degree relative) was documented in 4.8% (n=266). In this cohort, 92.1% (5067/5504) were live born infants (isolated and non-isolated birth defects): 75.3% (4147/5504) were classified as having an isolated birth defect (unknown or known etiology).Conclusions These findings underscore the gaps in our knowledge regarding the causes of birth defects. For the causes that are known, such as smoking or diabetes, assigning causation in individual cases remains challenging. Nevertheless, the ongoing impact of these exposures on fetal development highlights the urgency and benefits of population based preventive interventions. For the causes that are still unknown, better strategies are needed. These can include greater integration of the key elements of etiology, morphology, and pathogenesis into epidemiologic studies; greater collaboration between researchers (such as developmental biologists), clinicians (such as medical geneticists), and epidemiologists; and better ways to objectively measure fetal exposures (beyond maternal self reports) and closer (prenatally) to the critical period of organogenesis.

Mild orotic aciduria in UMPS heterozygotes: a metabolic finding without clinical consequences

BACKGROUND

Elevated urinary excretion of orotic acid is associated with treatable disorders of the urea cycle and pyrimidine metabolism. Establishing the correct and timely diagnosis in a patient with orotic aciduria is key to effective treatment. Uridine monophosphate synthase is involved in de novo pyrimidine synthesis. Uridine monophosphate synthase deficiency (or hereditary orotic aciduria), due to biallelic mutations in UMPS, is a rare condition presenting with megaloblastic anemia in the first months of life. If not treated with the pyrimidine precursor uridine, neutropenia, failure to thrive, growth retardation, developmental delay, and intellectual disability may ensue.

METHODS AND RESULTS

We identified mild and isolated orotic aciduria in 11 unrelated individuals with diverse clinical signs and symptoms, the most common denominator being intellectual disability/developmental delay. Of note, none had blood count abnormalities, relevant hyperammonemia or altered plasma amino acid profile. All individuals were found to have heterozygous alterations in UMPS. Four of these variants were predicted to be null alleles with complete loss of function. The remaining variants were missense changes and predicted to be damaging to the normal encoded protein. Interestingly, family screening revealed heterozygous UMPS variants in combination with mild orotic aciduria in 19 clinically asymptomatic family members.

CONCLUSIONS

We therefore conclude that heterozygous UMPS-mutations can lead to mild and isolated orotic aciduria without clinical consequence. Partial UMPS-deficiency should be included in the differential diagnosis of mild orotic aciduria. The discovery of heterozygotes manifesting clinical symptoms such as hypotonia and developmental delay are likely due to ascertainment bias.

Biallelic Variants in UBA5 Reveal that Disruption of the UFM1 Cascade Can Result in Early-Onset Encephalopathy

Via whole-exome sequencing, we identified rare autosomal-recessive variants in UBA5 in five children from four unrelated families affected with a similar pattern of severe intellectual deficiency, microcephaly, movement disorders, and/or early-onset intractable epilepsy. UBA5 encodes the E1-activating enzyme of ubiquitin-fold modifier 1 (UFM1), a recently identified ubiquitin-like protein. Biochemical studies of mutant UBA5 proteins and studies in fibroblasts from affected individuals revealed that UBA5 mutations impair the process of ufmylation, resulting in an abnormal endoplasmic reticulum structure. In Caenorhabditis elegans, knockout of uba-5 and of human orthologous genes in the UFM1 cascade alter cholinergic, but not glutamatergic, neurotransmission. In addition, uba5 silencing in zebrafish decreased motility while inducing abnormal movements suggestive of seizures. These clinical, biochemical, and experimental findings support our finding of UBA5 mutations as a pathophysiological cause for early-onset encephalopathies due to abnormal protein ufmylation.

Effect of dietary lysine restriction and arginine supplementation in two patients with pyridoxine-dependent epilepsy

Pyridoxine-Dependent Epilepsy (PDE) is a recessive disorder caused by deficiency of α-aminoadipic semialdehyde dehydrogenase in the catabolic pathway of lysine. It is characterized by intractable seizures controlled by the administration of pharmacological doses of vitamin B6. Despite seizure control with pyridoxine, intellectual disability and developmental delays are still observed in some patients with PDE, likely due to the accumulation of toxic intermediates in the lysine catabolic pathway: alpha-aminoadipic semialdehyde (AASA), delta-1-piperideine-6-carboxylate (P6C), and pipecolic acid. Here we evaluate biochemical and clinical parameters in two PDE patients treated with a lysine-restricted diet and arginine supplementation (100-150mg/kg), aimed at reducing the levels of PDE biomarkers. Lysine restriction resulted in decreased accumulation of PDE biomarkers and improved development. Plasma lysine but not plasma arginine, directly correlated with plasma levels of AASA-P6C (p<0.001, r(2)=0.640) and pipecolic acid (p<0.01, r(2)=0.484). In addition, plasma threonine strongly correlated with the levels of AASA-P6C (p<0.0001, r(2)=0.732) and pipecolic acid (p<0.005, r(2)=0.527), suggesting extreme sensitivity of threonine catabolism to pyridoxine availability. Our results further support the use of dietary therapies in combination with pyridoxine for the treatment of PDE.

Diagnosis, Treatment, and Clinical Outcome of Patients with Mitochondrial Trifunctional Protein/Long-Chain 3-Hydroxy Acyl-CoA Dehydrogenase Deficiency

Deficiency of the mitochondrial trifunctional protein (TFP) and long-chain 3-Hydroxy Acyl-CoA dehydrogenase (LCHAD) impairs long-chain fatty acid oxidation and presents with hypoglycemia, cardiac, liver, eye, and muscle involvement. Without treatment, both conditions can be life-threatening. These diseases are identified by newborn screening (NBS), but the impact of early treatment on long-term clinical outcome is unknown. Moreover, there is lack of consensus on treatment, particularly on the use of carnitine supplementation. Here, we report clinical and biochemical data in five patients with TFP/LCHAD deficiency, three of whom were diagnosed by newborn screening. All patients had signs and symptoms related to their metabolic disorder, including hypoglycemia, elevated creatine kinase (CK), and rhabdomyolysis, and experienced episodes of metabolic decompensation triggered by illness. Treatment was started shortly after diagnosis in all patients and consisted of a diet low in long-chain fats supplemented with medium chain triglycerides (MCT), essential fatty acids, and low-dose carnitine (25 mg/kg/day). Patients had growth restriction early in life that resolved after 2 years of age. All patients but the youngest (2 years old) developed pigmentary retinopathy. Long-chain hydroxylated acylcarnitines did not change significantly with age, but increased during acute illnesses. Free carnitine levels were maintained within the normal range and did not correlate with long-chain hydroxylated acylcarnitines. These results show that patients with LCHAD deficiency can have normal growth and development with appropriate treatment. Low-dose carnitine supplements prevented carnitine deficiency and did not result in increased long-chain hydroxylated acylcarnitines or any specific toxicity.

Bayesian multinomial probit modeling of daily windows of susceptibility for maternal PM2.5 exposure and congenital heart defects

Epidemiologic studies suggest that maternal ambient air pollution exposure during critical periods of pregnancy is associated with adverse effects on fetal development. In this work, we introduce new methodology for identifying critical periods of development during post-conception gestational weeks 2-8 where elevated exposure to particulate matter less than 2.5 µm (PM2.5 ) adversely impacts development of the heart. Past studies have focused on highly aggregated temporal levels of exposure during the pregnancy and have failed to account for anatomical similarities between the considered congenital heart defects. We introduce a multinomial probit model in the Bayesian setting that allows for joint identification of susceptible daily periods during pregnancy for 12 types of congenital heart defects with respect to maternal PM2.5 exposure. We apply the model to a dataset of mothers from the National Birth Defect Prevention Study where daily PM2.5 exposures from post-conception gestational weeks 2-8 are assigned using predictions from the downscaler pollution model. This approach is compared with two aggregated exposure models that define exposure as the average value over post-conception gestational weeks 2-8 and the average over individual weeks, respectively. Results suggest an association between increased PM2.5 exposure on post-conception gestational day 53 with the development of pulmonary valve stenosis and exposures during days 50 and 51 with tetralogy of Fallot. Significant associations are masked when using the aggregated exposure models. Simulation study results suggest that the findings are robust to multiple sources of error. The general form of the model allows for different exposures and health outcomes to be considered in future applications. Copyright © 2016 John Wiley & Sons, Ltd.

Lower rate of selected congenital heart defects with better maternal diet quality: a population-based study

OBJECTIVE

To evaluate whether better diet quality in mothers is associated with lower risk for major non-syndromic congenital heart defects in their children.

DESIGN

Multicentre population-based case-control study, the National Birth Defects Prevention Study.

SETTING

Ten sites in the USA.

PARTICIPANTS

Mothers of babies with major non-syndromic congenital heart defects (n=9885) and mothers with unaffected babies (n=9468) with estimated date of delivery from 1997 to 2009.

MAIN OUTCOME MEASURES

Adjusted ORs for specific major congenital heart defects by quartiles of maternal diet quality in the year before pregnancy, assessed by the Diet Quality Index for pregnancy (DQI-P) and the Mediterranean Diet Score. Quartile 1 (Q1) reflecting the worst diet quality and Q4 the best diet quality.

RESULTS

Better diet quality was associated with reduced risk for some conotruncal and atrial septal heart defects. For DQI-P, estimated risks reductions (Q4 vs Q1) for conotruncal defects were 37% for tetralogy of Fallot (OR 0.63, 95% CI 0.49 to 0.80) and 24% overall (OR 0.76, 95% CI 0.64 to 0.91); and for septal defects, 23% for atrial septal defects (OR 0.77, 95% CI 0.63 to 0.94) and 14% overall (OR 0.86, 95% CI 0.75 to 1.00). Risk reductions were weaker or minimal for most other major congenital heart defects.

CONCLUSIONS

Better diet quality is associated with a reduced occurrence of some conotruncal and septal heart defects. This finding suggests that a reduction in certain cardiac malformations may be an additional benefit of improved maternal diet quality, reinforcing current preconception care recommendations.

Building capacity for birth defects surveillance in Africa: Implementation of an intermediate birth defects surveillance workshop

Each year around the world, it is estimated that 300,000 neonates are born with a neural tube defect. Many countries, however, are still lacking comprehensive birth defects surveillance registries. Comprehensive birth defects surveillance systems can help countries understand the magnitude and distribution of the problem. These systems can also provide information about biological, contextual, social and environmental determinants of birth defects. This information in turn can be used to identify effective and implementable solutions, and to evaluate prevention and management strategies to improve quality performance. This paper summarizes the development and implementation of an online pre-course training and in-person surveillance workshop conducted between 2014 December and 2015 March for representatives from six African countries. Feedback given by participants provided valuable lessons learned that can be applied to subsequent trainings and workshops.

Elevated body mass index and decreased diet quality among women and risk of birth defects in their offspring

BACKGROUND

We examined whether risks of 32 birth defects were higher than expected in the presence of overweight or obese body mass index (BMI) and low diet quality, based on estimating individual and joint effects of these factors and calculating relative excess risk due to interaction.

METHODS

Analyses included mothers of 20,250 cases with birth defects and 8617 population-based controls without birth defects born from 1997 to 2009 and interviewed for the National Birth Defects Prevention Study. We used logistic regression to generate adjusted odds ratios (AORs) reflecting the combined effects of BMI and diet quality. We focused analyses on 16 birth defects (n = 11,868 cases, 8617 controls) for which initial results suggested an association with BMI or diet quality.

RESULTS

Relative to the reference group (normal weight women with not low diet quality, i.e., >lowest quartile), AORs for low diet quality among normal weight women tended to be >1, and AORs for overweight and obese women tended to be stronger among women who had low diet quality than not low diet quality. For 9/16 birth defects, AORs for obese women who had low diet quality-the group we hypothesized to have highest risk-were higher than other stratum-specific AORs. Most relative excess risk due to interactions were positive but small (<0.5), with confidence intervals that included zero.

CONCLUSION

These findings provide evidence for the hypothesis of highest birth defect risks among offspring to women who are obese and have low diet quality but insufficient evidence for an interaction of these factors in their contribution to risk.

Turner Syndrome in Girls Presenting with Coarctation of the Aorta

OBJECTIVE

To evaluate the frequency of Turner syndrome in a population-based, statewide cohort of girls with coarctation of the aorta.

STUDY DESIGN

The Utah Birth Defects Network was used to ascertain a cohort of girls between 1997 and 2011 with coarctation of the aorta. Livebirths with isolated coarctation of the aorta or transverse arch hypoplasia were included and patients with complex congenital heart disease not usually seen in Turner syndrome were excluded.

RESULTS

Of 244 girls with coarctation of the aorta, 77 patients were excluded, leaving a cohort of 167 girls; 86 patients (51%) had chromosomal studies and 21 (12.6%) were diagnosed with Turner syndrome. All patients were diagnosed within the first 4 months of life and 5 (24%) were diagnosed prenatally. Fifteen patients (71%) had Turner syndrome-related findings in addition to coarctation of the aorta. Girls with mosaicism were less likely to have Turner syndrome-associated findings (3/6 mosaic girls compared with 12/17 girls with non-mosaic 45,X). Twelve girls (57%) diagnosed with Turner syndrome also had a bicommissural aortic valve.

CONCLUSION

At least 12.6% of girls born with coarctation of the aorta have karyotype-confirmed Turner syndrome. Such a high frequency, combined with the clinical benefits of an early diagnosis, supports genetic screening for Turner syndrome in girls presenting with coarctation of the aorta.

Evaluating cost and resource use associated with pulse oximetry screening for critical congenital heart disease: Empiric estimates and sources of variation

BACKGROUND

Newborn screening for critical congenital heart disease (CCHD) using pulse oximetry is being implemented in the United States and internationally; however, few data are available on the associated in-hospital costs and use of resources.

METHODS

Time and motion study in well-baby nurseries at two large urban hospitals in Utah using different approaches to pulse oximetry screening. Two observers recorded the time for each screening step together with provider and equipment characteristics. Structured questionnaire provided additional information on labor and equipment costs.

RESULTS

Fifty-three CCHD screens were observed. At site A (n = 22), screening was mostly done by medical assistants (95%) using disposable probes (100%); at site B (n = 31), screening was mostly performed by certified nursing assistants (90%) using reusable probes (90%). Considering only first screens (n = 53), the median screen time was 8.6 min (range: 3.2-23.2), with no significant difference between sites. The overall cost ($ in 2014) of screening per baby was $24.52 at site A and $2.60 at site B. Nearly all the variation in cost (90%) was due to the cost of disposable probes; labor costs were similar between sites.

CONCLUSION

CCHD screening by means of pulse oximetry is reasonably fast for most babies, leading to relative small labor costs with little variation by provider type. The main driver of costs is equipment: in a high throughput setting, reusable probes are currently associated with considerable cost saving compared with disposable probes. As programs expand to universal screening, improved and cheaper technologies could lead to considerable economies of scale.

Maternal periconceptional alcohol consumption and congenital heart defects

BACKGROUND

Congenital heart defects (CHDs) are the leading cause of infant death from birth defects. Animal studies suggest in utero alcohol exposure is a teratogen for cardiogenesis; however, results from epidemiologic studies are mixed.

METHODS

Data from the National Birth Defects Prevention Study were used to estimate associations between CHDs and case (n = 7076) and control (n = 7972) mother reports of periconceptional (1 month before pregnancy through the first trimester) alcohol consumption with expected delivery dates during 1997 to 2007. CHDs were examined by category (conotruncal, septal, left ventricular outflow tract obstruction, and right ventricular outflow tract obstruction, heterotaxy with CHD) and subtype (e.g., tetralogy of Fallot [TOF]). Alcohol measures examined were any consumption, maximum average drinks per month, binge drinking, and alcohol type. Adjusted odds ratios and 95% confidence intervals were estimated using unconditional logistic regression analysis.

RESULTS

Increased risks, albeit marginally statistically significant, were observed for TOF and each maternal alcohol measure examined and for right ventricular outflow tract obstruction and heterotaxy with CHD and consumption of distilled spirits. Significantly reduced risks were observed for several CHD categories (septal defects, left ventricular outflow tract obstruction, and right ventricular outflow tract obstruction) and some corresponding subtypes with different alcohol measures. Significant risks were not observed for the other CHDs examined.

CONCLUSION

Analysis of this large, well-defined study sample did not show statistically significant increased risks between measures of maternal alcohol consumption and most CHDs examined. These findings may reflect, in part, limitations with retrospective exposure assessment or unmeasured confounders. Additional studies with continued improvement in measurement of alcohol consumption are recommended.

Prevalence of variants in methylenetetrahydrofolate reductase and the severity of pulmonary vascular disease

Pulmonary hypertension is a serious disease associated with constriction, cellular proliferation, inflammation, and in situ thrombosis of the small vessels of the lung. Some studies suggest that homozygous 677TT variants and compound heterozygous 677CT/1298AC variants in methylenetetrahydrofolate reductase may increase the risk for systemic vascular disease. We sought to determine the prevalence of variants in methylenetetrahydrofolate reductase in patients with pulmonary hypertension, and whether homozygous or compound heterozygous variants are associated with an increased severity of disease. The medical records of patients with pulmonary hypertension were retrospectively reviewed to identify 105 patients who were evaluated for variants in methylenetetrahydrofolate reductase. The frequency of the minor allele 677C > T was 0.352 and the frequency of the minor allele 1298A > C was 0.295. The number of patients who were homozygous 677TT, homozygous 1298CC or compound heterozygous 677CT/1298AC was similar to the number of control patients with corresponding variants in a meta-analysis of studies. Patients with homozygous or compound heterozygous variants had a significantly higher ratio of pulmonary to systemic vascular resistance (0.75 ± 0.07 vs. 0.56 ± 0.04, p = 0.019) during baseline heart catheterization. Twenty-five of 61 patients without, and 28 of 44 patients with, homozygous or compound heterozygous variants had moderate to severe disease (p = 0.030). Variants in methylenetetrahydrofolate reductase are common in the general population and in patients with pulmonary hypertension. It is unlikely that these variants cause pulmonary vascular disease; however, they may influence the progression or severity of disease.

Better diet quality before pregnancy is associated with reduced risk of gastroschisis in Hispanic women

BACKGROUND

Gastroschisis is unique because of its substantial risk in pregnancies of adolescent women. Adolescents may have poor diet quality, which places them at higher risk of gastroschisis.

OBJECTIVE

We investigated whether better maternal diet quality, measured by 2 different indices, reduced the risk of gastroschisis.

METHODS

We used case-control data from the National Birth Defects Prevention Study to investigate maternal diet quality among 1125 gastroschisis cases and 9483 controls (estimated delivery dates between 1997 and 2009). Cases were ascertained from 10 U.S. birth defect surveillance systems. Control subjects were randomly selected from birth certificates or hospital records. Using a 58-item food-frequency questionnaire, interviewers queried mothers about their average food and cereal intake during the year before conception. Diet quality scores [Diet Quality Index (DQI) and Mediterranean diet score (MDS)] were calculated using specific components. Women were excluded if they consumed <500 or >5000 kcal/d, reported pregestational diabetes, or had >1 missing food item. Quartile-specific adjusted ORs (aORs) were calculated, using as reference the lowest quartile.

RESULTS

Overall, we observed a statistically significant decrease with increasing diet quality for both the DQI and MDS. When stratified by maternal race/ethnicity, this finding was confined to Hispanic women. Among Hispanic women, the risk of gastroschisis decreased significantly with increasing DQI quartiles: quartile 2, aOR = 0.58 (95% CI: 0.40, 0.86); quartile 3, aOR = 0.52 (95% CI: 0.36, 0.79); and quartile 4, aOR = 0.48 (95% CI: 0.32, 0.76). Increasing diet quality, as measured by the MDS, showed reduced risk of gastroschisis among women, mostly Hispanic, who were born outside the United States: quartile 2, aOR = 0.62 (95% CI: 0.33, 1.16); quartile 3, aOR = 0.51 (95% CI: 0.28, 0.94); and quartile 4, aOR = 0.50 (95% CI: 0.28, 0.90).

CONCLUSIONS

Increasing diet quality was associated with a reduced risk of gastroschisis only among Hispanic and foreign-born women, but these findings require replication.

Laterality defects in the national birth defects prevention study (1998-2007): birth prevalence and descriptive epidemiology

Little is known epidemiologically about laterality defects. Using data from the National Birth Defects Prevention Study (NBDPS), a large multi-site case-control study of birth defects, we analyzed prevalence and selected characteristics in children born with laterality defects born from 1998 to 2007. We identified 517 nonsyndromic cases (378 heterotaxy, 73.1%; 139 situs inversus totalis [SIT], 26.9%) resulting in an estimated birth prevalence of 1.1 per 10,000 live births (95% confidence interval 1.0–1.2). Prevalence did not differ significantly across sites, over time, or by inclusion of pregnancy termination. Laterality defects were more common among preterm cases compared to term cases, and in children born to mothers who were non-white or younger than 20 years compared to white mothers or those age 25–29 years. The distribution of associated cardiac and extra-cardiac defects, excluding the expected heterotaxy anomalies, varied by type of laterality defect. Cases with heterotaxy were significantly more likely than those with SIT to have double outlet right ventricle, atrioventricular canal defects, pulmonary stenosis, non-tetralogy of Fallot pulmonary atresia with ventricular septal defect, totally and partially anomalous pulmonary venous return; also more likely to have orofacial clefts, esophageal atresia, bowel atresias, and omphalocele, though not reaching statistical significance. Relatively more common among cases with SIT were Dandy- Walker malformation, anotia/microtia, and limb deficiency. The similarity in the demographic characteristics of heterotaxy and SIT supports the hypothesis that they are part of a continuum of abnormal left-right axis patterning. These findings on laterality defects may help guide clinical care, future research, and prevention strategies.