Birth Defects Research Research Articles

Animal Embryotoxicity Studies of Key Non-Artemisinin Antimalarials and Use in Women in the First Trimester.

The World Health Organization currently recommends quinine+clindamycin for use against malaria in the first trimester. This may soon change to recommending artemisinin-based combination therapies (standard duration of dosing = 3 days). The non-artemisinin partner drugs include amodiaquine, lumefantrine, mefloquine, piperaquine, sulfadoxine+pyrimethamine, and pyronaridine. For quinine, clindamycin, and mefloquine and the combinations of sulfadoxine+pyrimethamine and artemether+lumefantrine, there are reports (including studies without internal comparison groups) that combined describe 304 to >1100 exposures of women in the first trimester for each drug with no conclusive evidence of adverse effects on pregnancy at therapeutic doses. This is despite the fact that all of these drugs or drug combinations caused embryo deaths and/or malformations in at least one animal species and all except lumefantrine had at least one exposure ratio <1. It now seems that these animal studies overestimated the risk of developmental toxicity in women with malaria. Three other non-artemisinins (amodiaquine, piperaquine, and pyronaridine) have few or no reported exposures in women in the first trimester and have exposure ratios ≤2 based on studies in pregnant rats and rabbits with dosing throughout organogenesis. However, none of these drugs caused embryo deaths or malformations in pregnant rats and rabbits with the exception of pyronaridine, which caused embryo deaths only at a dose that was excessively toxic to the mothers. Thus, for amodiaquine, piperaquine, and pyronaridine, the testing in animals did not reveal findings of concern and the exposure ratios were in the range of the other non-artemisinin antimalarials described above. Birth Defects Research 109:1075-1126, 2017. © 2017 The Authors. Birth Defects Research Published by Wiley Periodicals, Inc.

Assisted Reproductive Technology and Birth Defects: Effects of Subfertility and Multiple Births.

Assisted reproductive technology (ART) has been associated with birth defects, but the contributions of multiple births and underlying subfertility remain unclear. We evaluated the effects of subfertility and mediation by multiple births on associations between ART and nonchromosomal birth defects. We identified a retrospective cohort of Massachusetts live births and stillbirths from 2004 to 2010 among ART-exposed, ART-unexposed subfertile, and fertile mothers using linked information from fertility clinics, vital records, hospital discharges, and birth defects surveillance. Log-binomial regression was used to estimate prevalence ratios and 95% confidence intervals (CIs). Mediation analyses were performed to deconstruct the ART-birth defects association into the direct effect of ART, the indirect effect of multiple births, and the effect of ART-multiples interaction. Of 17,829 ART-exposed births, 355 had a birth defect, compared with 162 of 9431 births to subfertile mothers and 6183 of 445,080 births to fertile mothers. The adjusted prevalence ratio was 1.5 (95% CI, 1.3-1.6) for ART and 1.3 (95% CI, 1.1-1.5) in subfertile compared with fertile deliveries. We observed elevated rates of several birth defects with ART, including tetralogy of Fallot and hypospadias. Subfertility and multiple births affect these associations, with multiple births explaining 36% of the relative effect of ART on nonchromosomal birth defects. Although the risk of birth defects with ART is small, a substantial portion of the relative effect is mediated through multiple births, with subfertility contributing an important role. Future research is needed to determine the impact of newer techniques, such as single embryo transfer, on these risks. Birth Defects Research 109:1144-1153, 2017. © 2017 Wiley Periodicals, Inc.

Maternal Smoking, Alcohol, and Caffeine Exposures and Risk of Hypospadias.

We examined the association of hypospadias risk with maternal smoking and consumption of alcohol and caffeine. We analyzed data from mothers of 2437 moderate/severe cases and 5472 nonmalformed controls born from 1997 to 2011 who participated in the National Birth Defects Prevention Study (NBDPS). Exposures were assessed by maternal telephone interviews. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) adjusted for mother's age, parity, race-ethnicity, education, vitamin/mineral supplement intake, obesity, and study center. Active smoking during the first month of pregnancy was associated with reduced risk, with smaller ORs for increasing quantity smoked; the OR for smoking >1/2 pack/day was 0.7 (95% CI, 0.5-0.9). Among nonsmokers, the OR for any secondhand smoke exposure was 0.8 (95% CI, 0.7-0.9). ORs for alcohol and caffeine consumption were near one and CIs included 1.0. In an analysis of joint exposures to smoking and alcohol and caffeine consumption, the only OR for which the 95% CI excluded 1.0 was for women who smoked, drank, and had low caffeine consumption (OR, 0.6; 95% CI, 0.4-0.8). Maternal exposure to cigarette smoke was associated with reduced risk, and women who smoked, drank, and had low caffeine intake were at lowest risk. We do not interpret these results to suggest that these exposures have overall benefit to a pregnant woman or developing fetus. They may, however, offer clues to help us understand mechanisms that lead to hypospadias. Birth Defects Research 109:1127-1133, 2017. © 2017 Wiley Periodicals, Inc.

Chlamydia trachomatis Is Responsible for Lipid Vacuolation in the Amniotic Epithelium of Fetal Gastroschisis.

Vacuolated amniotic epithelium with lipid droplets in gastroschisis placentas is an unusual finding. Mass spectrometry of lipid droplets identified triglycerides, ester-linked to an unusual pattern of fatty acids. We hypothesize that these findings result from a Chlamydia trachomatis infection during the periconceptional period. The rising incidence of chlamydia infections has paralleled the increasing prevalence of gastroschisis among women less than 25 years of age. Histologically, young women are at greatest risk for a chlamydia infection due to their immature columnar epithelium, the preferential site for attachment of Chlamydia trachomatis infectious particle (elementary body). Chlamydia trachomatis survive in an inclusion, relying on its host to acquire essential nutrients, amino acids, and nucleotides for survival and replication. If essential nutrients are not available, the bacteria cannot replicate and may be trafficked to the lysosome for degradation or remain quiescent, within the inclusion, subverting innate immunologic clearance. Chlamydiae synthesize several lipids (phosphatidylethanolamine, phosphatidylserine, and phosphoatidylglycerol); however, their lipid content reveal eukaryotic lipids (sphingomyelin, cholesterol, phosphatidylcholine, and phosphatidylinositol), evidence that chlamydiae "hijack" host lipids for expansion and replication. The abnormal amniotic epithelial findings are supported by experimental evidence of the trafficking of host lipids into the chlamydiae inclusion. If not lethal, what harm will elementary bodies inflict to the developing embryo? Do these women have a greater pro-inflammatory response to an environmental exposure, whether cigarette smoking, change in partner, or a pathogen? Testing the hypothesis that Chlamydia trachomatis is responsible for amniotic epithelium vacuoles will be a critical first step. Birth Defects Research 109:1003-1010, 2017. © 2017 Wiley Periodicals, Inc.

Prevalence of Orofacial Clefts among Live Births in China: A Systematic Review and Meta-Analysis.

Orofacial clefts (OFCs) are common human birth defects in China. However, studies on the prevalence of OFCs present inconsistent results. The overall prevalence and geographic distribution of OFCs are poorly described in China. Thus, we conducted a systematic review and meta-analysis to estimate the prevalence of OFCs. The systematic review and meta-analysis were conducted on the basis of an established protocol (PROSPERO 2015: CRD42015030198). We systematically searched for articles in four electronic databases, including Embase, PubMed, Wanfang Database, and China National Knowledge Infrastructure (CNKI) to identify relevant studies about prevalence of OFCs in China. Meta-analysis, including subgroup analysis, was conducted to estimate the pooled prevalence. A total of 41 studies published between 1986 and 2015 were included in our analysis. The sample size ranged from 2,586 to 4,611,808 live births. The random-effects model of meta-analysis showed that the overall prevalence of OFCs in China was 1.4 per 1000 live births (95% confidence interval [CI], 1.1-1.7). In subgroup analysis based on geographic regions, we found that OFC prevalence in Southwest (2.3 per 1000 live births, 95% CI, 1.1-4.7) was higher than that in other regions of China. There were no significant time trends of OFCs during the study period (p-value = 0.47). The overall prevalence of OFCs in China was 1.4 per 1000 live births. No significant secular trend of prevalence has been found in this analysis. Further studies need to be conducted to explore the etiology of OFC to better control the risk of this common birth defect. Birth Defects Research 109:1011-1019, 2017. © 2017 Wiley Periodicals, Inc.

Exposure to Sodium Valproate during Pregnancy: Facial Features and Signs of Autism.

Valproic acid (VPA) is the most teratogenic anticonvulsant drug in clinical use today. Children exposed prenatally to VPA have previously been shown to have dysmorphic craniofacial features, identified subjectively but not by anthropometric methods. Exposure to VPA has also been associated with an increased frequency of autism spectrum disorder (ASD). An increased cephalic index (the ratio of the cranial lateral width to the cranial anterior-posterior length) has been observed in children with ASD. Forty-seven children exposed to VPA during the first trimester of pregnancy were evaluated for dysmorphic facial features, identified subjectively and by measurements. Each VPA-exposed child was evaluated for ASD using the Social Communication Questionnaire, Autism Diagnostic Interview-Revised, and Autism Diagnostic Observation Schedule. The same physical examination was carried out on an unexposed comparison group of 126 children. The unexposed children also had testing for cognitive performance by the Wechsler Intelligence Scale for Children. Several dysmorphic craniofacial features, including telecanthus, wide philtrum, and increased length of the upper lip were identified subjectively. Anthropometric measurements confirmed the increased intercanthal distance and documented additional findings, including an increased cephalic index and decreased head circumference/height index. There were no differences between the craniofacial features of VPA-exposed children with and without ASD. An increased frequency of dysmorphic craniofacial features was identified in children exposed to VPA during the first trimester of pregnancy. The most consistent finding was a larger cephalic index, which indicates a disproportion of increased width of the skull relative to the shortened anterior-posterior length. Birth Defects Research 109:1134-1143, 2017. © 2017 Wiley Periodicals, Inc.

Genetic Risk Factors for Folate-Responsive Neural Tube Defects.

Neural tube defects (NTDs) are the most severe congenital malformations of the central nervous system. The etiology is complex, with both genetic and environmental factors having important contributions. Researchers have known for the past two decades that maternal periconceptional use of the B vitamin folic acid can prevent many NTDs. Though this finding is arguably one of the most important recent discoveries in birth defect research, the mechanism by which folic acid exerts this benefit remains unknown. Research to date has focused on the hypothesis that an underlying genetic susceptibility interacts with folate-sensitive metabolic processes at the time of neural tube closure. Little progress has been made searching for risk-causative variants in candidate genes; therefore, more complex genetic and epigenetic methodologies are now being considered. This article reviews the research to date that has been targeted on this important gene-nutrient locus.

Effect of Concomitant Birth Defects and Genetic Anomalies on Infant Mortality in Tetralogy of Fallot.

A substantial proportion of infants born with tetralogy of Fallot (TOF) die in infancy. A better understanding of the heterogeneity associated with TOF, including extracardiac malformations and chromosomal anomalies is vital to stratifying risk and optimizing outcomes during infancy. Using the North Carolina Birth Defects Monitoring Program, infants diagnosed with TOF and born between 2003 and 2012 were included. Kaplan-Meier survival curves were used to estimate cumulative 1-year mortality, stratified by the presence of concomitant birth defects (BDs) and chromosomal anomalies. Multivariable logistic regression was used to estimate the direct effect of each concomitant BD, after adjusting for all others. A total of 496 infants with TOF were included, and 15% (n = 76) died. The number of concomitant BD systems was significantly associated with the risk of death at 1-year, p < 0.0001. Specifically, the risk of mortality was 8% among infants with TOF with or without additional cardiac defects, 16% among infants with TOF and 1 extracardiac BD system, 19% among infants with 2 extracardiac BD systems, and 39% among infants with ≥ 3 extracardiac BD systems. After adjustment, concomitant eye and gastrointestinal defects were significantly associated increased with 1-year mortality, odds ratio 2.83 (95% confidence interval, 1.08-7.32) and odds ratio 4.43 (95% confidence interval, 1.57, 12.45), respectively. Infants with trisomy 13 or trisomy 18 were also significantly more likely to die, p < 0.0001. Both concomitant BDs and genetic anomalies increase the risk of mortality among infants with TOF. Future studies are needed to identify the underlying genetic and socioeconomic risk factors for high-risk TOF infants. Birth Defects Research 109:1154-1165, 2017. © 2017 Wiley Periodicals, Inc.

Ambient and Dosed Exposure to Quaternary Ammonium Disinfectants Causes Neural Tube Defects in Rodents.

BackgroundQuaternary ammonium compounds are a large class of chemicals used for their antimicrobial and antistatic properties. Two common quaternary ammonium compounds, alkyldimethylbenzyl ammonium chloride (ADBAC) and didecyldimethyl ammonium chloride (DDAC), are combined in common cleaners and disinfectants. Introduction of a cleaner containing ADBAC+DDAC in the vivarium caused neural tube defects (NTDs) in mice and rats.MethodsTo further evaluate this finding, male and female mice were dosed in the feed at 60 or 120 mg/kg/day, or by oral gavage at 7.5, 15, or 30 mg/kg ADBAC+DDAC. Mice also received ambient exposure to ADBAC+DDAC from the disinfectant used in the mouse room. Embryos were evaluated on gestational day 10 for NTDs, and fetuses were evaluated on gestational day 18 for gross and skeletal malformations.ResultsWe found increased NTDs with exposure to ADBAC+DDAC in both rats and mice. The NTDs persisted for two generations after cessation of exposure. Notably, male exposure alone was sufficient to cause NTDs. Equally significant, ambient exposure from disinfectant use in the vivarium, influenced the levels of NTDs to a greater extent than oral dosing. No gross or significant axial skeletal malformations were observed in late gestation fetuses. Placental abnormalities and late gestation fetal deaths were increased at 120 mg/kg/day, which might explain the lack of malformations observed in late gestation fetuses.ConclusionThese results demonstrate that ADBAC+DDAC in combination are teratogenic to rodents. Given the increased use of these disinfectants, further evaluation of their safety in humans and their contribution to health and disease is essential.

Array-based molecular karyotyping in 115 VATER/VACTERL and VATER/VACTERL-like patients identifies disease-causing copy number variations.

The acronym VATER/VACTERL refers to the rare nonrandom association of the following component features (CF): vertebral defects (V), anorectal malformations (A), cardiac defects (C), tracheoesophageal fistula with or without esophageal atresia, renal malformations (R), and limb defects (L). Patients presenting with at least three CFs are diagnosed as having VATER/VACTERL association while patients presenting with only two CFs are diagnosed as having VATER/VACTERL-like phenotypes. Recently, rare causative copy number variations (CNVs) have been identified in patients with VATER/VACTERL association and VATER/VACTERL-like phenotypes. To detect further causative CNVs we performed array based molecular karyotyping in 75 VATER/VACTERL and 40 VATER/VACTERL-like patients. Following the application of stringent filter criteria, we identified 13 microdeletions and seven microduplications in 20 unrelated patients all of which were absent in 1,307 healthy inhouse controls (n < 0.0008). Among these, microdeletion at 17q12 was confirmed to be de novo. Three microdeletions at 5q23.1, 16q23.3, 22q11.21, and one microduplication at 10q11.21 were all absent in the available parent. Microdeletion of chromosomal region 22q11.21 was previously found in VATER/VACTERL patients rendering it to be causative in our patient. The remaining 15 CNVs were inherited from a healthy parent. In two of 115 patients' causative CNVs were found (2%). The remaining identified rare CNVs represent candidates for further evaluation. Rare inherited CNVs may constitute modifiers of, or contributors to, multifactorial VATER/VACTERL or VATER/VACTERL-like phenotypes. Birth Defects Research 109:1063-1069, 2017. © 2017 Wiley Periodicals, Inc.

School absence and its effect on school performance for children born with orofacial clefts.

School absence is associated with lower performance on standardized tests. Children born with orofacial clefts (OFC) are likely to have more absence than children without OFC; however, school absence for children with OFC has not been quantified. We aimed to describe school absence and its relationship with school performance for children with and without OFC. Population-based record-linked cohort study of children (402 with OFC, 1789 without OFC) enrolled in schools in Western Australia, 2008 to 2012. We compared median school absence rates using Wilcoxon rank tests, and investigated the impact of school absence on standardized scores from reading, numeracy, and writing tests, using multivariable models fitted by generalized estimating equations. In Semester 1, at each primary school year level, children without OFC and children with cleft lip only or cleft palate only had similar median absence rates (approximately 1 week). Children with cleft lip and palate had significantly higher absence rates in Years 4 to 6 (between 1 and 2 weeks). During secondary school, median absence rates were higher (2 weeks) for all children, but not statistically different between children with and without OFC. Higher absence was significantly associated with lower standardized reading, numeracy, and writing scores. However, having a cleft of any type had little influence on the association between absence and test scores. School absence affected school performance for all children. Absence did not differentially disadvantage children born with OFC, suggesting current practices to identify and support children with OFC are minimizing effects of their absence on school performance. Birth Defects Research 109:1048-1056, 2017. © 2017 Wiley Periodicals, Inc.

Chromosome copy number variants in fetuses with syndromic malformations.

Chromosome copy number variants (CNVs; gains and losses of DNA sequences >1 kb) are wide-spread throughout the genome of healthy individuals. Laboratory studies show that a subset of CNVs are pathogenic, and not only can be responsible for the pathogenesis of major birth defects and cancer, but are also associated with neurodevelopmental disorders at birth. The characteristics of the pathogenic microdeletions and microduplications are important for both clinical implications and genetic counselling regarding test selection for prenatal screening and diagnosis. Unfortunately, our knowledge of the phenotypic effects of most CNV is still minimal, leading to the classification of many CNVs as "genomic imbalances of unknown clinical significance". Microdeletions and microduplications can occur in all pregnancies and the spectrum of pathogenic CNVs in fetuses with syndromic malformations is not well studied. This review summarizes our current understanding of CNVs, the common detection methods, and the characteristics of pathogenic CNVs identified in fetuses with syndromic malformations. Birth Defects Research 109:725-733, 2017. © 2017 Wiley Periodicals, Inc.

Plasma folate levels and associated factors in women planning to become pregnant in a population with high prevalence of neural tube defects.

Optimal blood folate levels of women before pregnancy are critical to the prevention of neural tube defects (NTDs). However, few studies have focused on blood folate levels of women planning to become pregnant. The aims of this study were to assess plasma folate levels in women who planned to become pregnant in a population with high prevalence of NTDs, to identify factors associated with plasma folate levels, and to evaluate the risk of NTDs at the population level. A total of 2065 women were enrolled at the time of premarital health check-up in two rural counties in northern China from November 2009 to December 2012. Fasting venous blood samples were collected and plasma folate concentrations were measured by microbiological method. The overall median of plasma folate was 10.5 nmol/L. 50% of the women had a plasma folate level below 10.5 nmol/L, a cutoff for megaloblastic anemia, and 88% below 18 nmol/L, a proposed optimal plasma folate level for the prevention of NTDs. Folic acid supplementation was the only factor to be associated with plasma folate concentrations, but only 1.9% of the women reported having taken folic acid supplements. A population risk of 29.3 NTD cases per 10,000 births was predicted. Women who planned to become pregnant had very low plasma folate in the population. Folic acid supplementation was the only factor to be associated with a high plasma folate concentration. High NTD risk would remain if women would get pregnant without having taken folic acid supplements. Birth Defects Research 109:1039-1047, 2017. © 2017 Wiley Periodicals, Inc.

Phenotyping cardiac and structural birth defects in fetal and newborn mice.

Mouse models are invaluable for investigating the developmental etiology and molecular pathogenesis of structural birth defects. While this has been deployed for studying a wide spectrum of birth defects, mice are particularly valuable for modeling congenital heart disease, given they have the same four-chamber cardiac anatomy as in humans. We have developed the use of noninvasive fetal ultrasound together with micro-computed tomography (micro-CT) imaging for high throughput phenotyping of mice for congenital heart defects (CHD) and other developmental anomalies. We showed the efficacy of fetal ultrasound and micro-CT imaging for diagnosis of a wide spectrum of CHD. With fetal ultrasound, longitudinal scans can be conducted to track the developmental profile of disease pathogenesis, providing both structural information with two-dimensional (2D) imaging, as well as functional data from hemodynamic assessments with color flow and spectral Doppler imaging. In contrast, with micro-CT imaging, virtual necropsies can be conducted rapidly postmortem for diagnosis of not only CHD, but also other structural birth defects. To validate the CHD diagnosis, we further showed the use of a novel histological technique with episcopic confocal microscopy to obtain rapid 3D reconstructions for accurate diagnosis of even the most complex anatomical defect. The latter histological imaging technique when combined with the use of ultrasound and micro-CT imaging provides a powerful combination of imaging modalities that will be invaluable in meeting the accelerating demands for high throughput mouse phenotyping of genetically engineered mice in the coming age of functional genomics. Birth Defects Research 109:778-790, 2017. © 2017 Wiley Periodicals, Inc.

Diverse application of MRI for mouse phenotyping.

Small animal models, particularly mouse models, of human diseases are becoming an indispensable tool for biomedical research. Studies in animal models have provided important insights into the etiology of diseases and accelerated the development of therapeutic strategies. Detailed phenotypic characterization is essential, both for the development of such animal models and mechanistic studies into disease pathogenesis and testing the efficacy of experimental therapeutics. MRI is a versatile and noninvasive imaging modality with excellent penetration depth, tissue coverage, and soft tissue contrast. MRI, being a multi-modal imaging modality, together with proven imaging protocols and availability of good contrast agents, is ideally suited for phenotyping mutant mouse models. Here we describe the applications of MRI for phenotyping structural birth defects involving the brain, heart, and kidney in mice. The versatility of MRI and its ease of use are well suited to meet the rapidly increasing demands for mouse phenotyping in the coming age of functional genomics. Birth Defects Research 109:758-770, 2017. © 2017 Wiley Periodicals, Inc.

Cornelia de Lange syndrome: To diagnose or not to diagnose in utero?

Cornelia de Lange syndrome (CdLS) is an inherited condition with a wide spectrum of phenotypic anomalies, consisting mainly of growth impairment, multi-organ abnormalities, and neurocognitive delay. Clinical diagnostic criteria after birth are well defined, whereas when to suspect the syndrome during intrauterine life still remains undefined. This review summarizes the main possible prenatal findings in CdLS, suggesting that a skilled ultrasound scan in cases of intrauterine growth restriction associated with other fetal abnormalities may improve the chance of prenatal diagnosis of CdLS, especially in families known to be at high risk. We propose that, following a sequence of detailed scans and examinations, CdLS affected fetuses could be diagnosed in utero, when one or more conditions (among them, intrauterine growth restriction, limb defects, facial abnormalities, diaphragmatic hernia, and heart diseases) are detected, and possibly confirmed by specific molecular testing. Birth Defects Research 109:771-777, 2017. © 2017 The Authors. Birth Defects Research Published by Wiley Periodicals, Inc.

Screening, genetics, risk factors, and treatment of neonatal cataracts.

Neonatal cataracts remain the most common cause of visual loss in children worldwide and have diverse, often unknown, etiologies. This review summarizes current knowledge about the detection, treatment, genetics, risk factors, and molecular mechanisms of congenital cataracts. We emphasize significant progress and topics requiring further study in both clinical cataract therapy and basic lens research. Advances in genetic screening and surgical technologies have improved the diagnosis, management, and visual outcomes of affected children. For example, mutations in lens crystallins and membrane/cytoskeletal components that commonly underlie genetically inherited cataracts are now known. However, many questions still remain regarding the causes, progression, and pathology of neonatal cataracts. Further investigations are also required to improve diagnostic criteria for determining the timing of appropriate interventions, such as the implantation of intraocular lenses and postoperative management strategies, to ensure safety and predictable visual outcomes for children. Birth Defects Research 109:734-743, 2017. © 2017 Wiley Periodicals, Inc.

Sirenomelia: A Multi‐systemic Polytopic Field Defect with Ongoing Controversies

The most impressive phenotypic appearance of sirenomelia is the presence of a 180°-rotated, axially positioned, single lower limb. Associated gastrointestinal and genitourinary anomalies are almost always present. This rare anomaly is still the subject of ongoing controversies concerning its nosology, pathogenesis, and possible genetic etiology. Sirenomelia can be part of a syndromic continuum, overlapping with other complex conditions including caudal dysgenesis and VATER/VACTERL/VACTERL-H associations, which could all be part of a heterogeneous spectrum, and originate from an early defect in blastogenesis. It is imaginable that different "primary field defects," whether or not genetically based, induce a spectrum of caudal malformations. In the current study, we review the contemporary hypotheses and conceptual approaches regarding the etiology and pathogenesis of sirenomelia, especially in the context of concomitant conditions. To expand on the latter, we included the external and internal dysmorphology of one third trimester sirenomelic fetus from our anatomical museum collection, in which multiple concomitant but discordant anomalies were observed compared with classic sirenomelia, and was diagnosed as VACTERL-H association with sirenomelia. Birth Defects Research 109:791-804, 2017. © 2017 The Authors. Birth Defects Research Published by Wiley Periodicals, Inc.

"Three Hits" Hypothesis for Developmental Origins of Health and Diseases in View of Cardiovascular Abnormalities.

"Fetal Origins of Adult Diseases" (FOAD) or "Barker hypothesis," also known as the developmental origins of health and diseases (DoHaD), was initially proposed by David Barker in the 1980s. Progress in past 2 to 3 decades demonstrated that many adult disorders, including hypertension, diabetes, obesity, cancer, and others, could be linked to poor development resulting from in utero insults. Utero-environments play a critical role in fetal development. Because the placenta and umbilical cord are the only important connections between the fetus and mother in the uterus, this review pays special attention to recent research and progress in the study of the relationship between those tissues and FOAD. We discuss the conception and possible underlying mechanisms of FOAD, and focus on cardiovascular diseases and epigenetic mechanisms. This review also summarizes physiology, pathology, and the important roles of fetoplacental vasculature, which might contribute to FOAD as initiators. We proposed the "Three hits" hypothesis that highlights the importance of intrauterine and early postnatal factors as contributors to FOAD, which could be significant for early prevention and treatments of FOAD. Birth Defects Research 109:744-757, 2017. © 2017 Wiley Periodicals, Inc.

Genetic vulnerabilities to prenatal alcohol exposure: Limb defects in sonic hedgehog and GLI2 heterozygous mice.

Genetic factors influence the physical and neurobehavioral manifestations of prenatal alcohol exposure (PAE). Animal models allow the investigation of specific genes that confer vulnerability to, or protection from, birth defects associated with fetal alcohol spectrum disorders (FASDs). The objective of the present experiments was to determine if genetic alterations in the Sonic Hedgehog (Shh) signaling pathways affect the vulnerability to PAE-induced skeletal defects involving the forelimbs and/or hindlimbs. Wild-type C57BL/6J female mice were bred with males in which one copy of the Shh or Gli2 genes had been knocked out, to produce litters with both wild-type (+/+) and heterozygous (+/-) embryos. Alcohol doses (two injections of 2.9 g/kg, 4 hours apart) or vehicles were administered starting at gestational day (GD) 9.25, 9.5, or 9.75, a critical exposure time for inducing limb defects. Limb defects were examined at GD 17 using a dysmorphology scale based on abnormalities ranging from increased interdigital spacing to the deletion of multiple fingers and the ulna. Alcohol treatment caused a high incidence of forelimb defects, particularly on the right side, that was higher in Shh+/- and Gli2+/- fetuses compared to wild-type fetuses. Dysmorphology scores were also significantly higher in the Shh+/- and Gli2+/- mice. These results extend previous findings demonstrating enhanced sensitivity to PAE-induced craniofacial dysmorphology and support the hypothesis that genetic alterations in the Shh signaling pathway influences the vulnerability to alcohol-induced birth defects. Moreover, these results emphasize the importance of understanding the interactions between genes and prenatal exposure to alcohol or other teratogens. Birth Defects Research 109:860-865, 2017. © 2017 Wiley Periodicals, Inc.