Birth Defects Res A Clin Mol Teratol
· 2015 Jun · PMID 25808073
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BACKGROUND: The C677T polymorphism in the methylenetetrahydrofolate reductase gene (MTHFR) gene has been reported to play a critical role in the pathogenesis of neural tube defects (NTDs). The association of the C677T po...BACKGROUND: The C677T polymorphism in the methylenetetrahydrofolate reductase gene (MTHFR) gene has been reported to play a critical role in the pathogenesis of neural tube defects (NTDs). The association of the C677T polymorphism in the MTHFR gene and NTD susceptibility has been widely demonstrated, but the results are inconclusive. In this study, we performed a meta-analysis in three groups to investigate the association between the MTHFR C677T polymorphism and NTD risk. METHODS: A computer retrieval of PubMed, Cochrane Library, CBM, and Embase for papers on the MTHFR C677T polymorphism and NTD risk was performed. All data were analyzed with STATA (Version 13.0). Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association. A test for heterogeneity, a sensitivity analysis, and an assessment of publication bias were performed in our meta-analysis. RESULTS: Forty articles were included in this meta-analysis: 13 studies for Group A: 1329 NTD patients versus 2965 healthy controls; 34 studies for Group B: 3018 mothers with NTD progeny versus 8746 healthy controls; three studies for Group C: 157 fathers with NTD progeny versus 705 healthy controls. The analysis results show: allele contrast in NTD patients: OR = 1.445, 95% CI [1.186, 1.760]; allele contrast in mothers: OR = 1.342, 95% CI [1.166, 1.544]; allele contrast in fathers: OR = 1.062, 95% CI [0.821, 1.374]. CONCLUSION: We found no association between any of the fathers' genotypes and NTDs, whereas a significant correlation between MTHFR C677T polymorphism and NTD risk was found in NTD patients and in their mother.
Younkin SG, Scharpf RB, Schwender H
… +5 more, Parker MM, Scott AF, Marazita ML, Beaty TH, Ruczinski I
Birth Defects Res A Clin Mol Teratol
· 2015 Apr · PMID 25776870
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BACKGROUND: DNA copy number variants play an important part in the development of common birth defects such as oral clefts. Individual patients with multiple birth defects (including oral clefts) have been shown to carry...BACKGROUND: DNA copy number variants play an important part in the development of common birth defects such as oral clefts. Individual patients with multiple birth defects (including oral clefts) have been shown to carry small and large chromosomal deletions. METHODS: We investigated the role of polymorphic copy number deletions by comparing transmission rates of deletions from parents to offspring in case-parent trios of European ancestry ascertained through a cleft proband with trios ascertained through a normal offspring. DNA copy numbers in trios were called using the joint hidden Markov model in the freely available PennCNV software. All statistical analyses were performed using Bioconductor tools in the open source environment R. RESULTS: We identified a 67 kb region in the gene MGAM on chromosome 7q34, and a 206 kb region overlapping genes ADAM3A and ADAM5 on chromosome 8p11, where deletions are more frequently transmitted to cleft offspring than control offspring. CONCLUSIONS: These genes or nearby regulatory elements may be involved in the etiology of oral clefts.
Birth Defects Res A Clin Mol Teratol
· 2015 Jun · PMID 25776730
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BACKGROUND: Neural tube defects (NTDs) remain the second most common cause of congenital malformations. Myelomeningocele (MM), the most common NTD compatible with survival, results from genetic and environmental factors....BACKGROUND: Neural tube defects (NTDs) remain the second most common cause of congenital malformations. Myelomeningocele (MM), the most common NTD compatible with survival, results from genetic and environmental factors. Epidemiologic studies and murine models support the hypotheses that obesity, diabetes and hyperglycemia confer increased risk of NTDs. Presence of wild-type facilitated glucose transporter, Glut2, in mouse embryos has been shown to increase risk for NTDs in hyperglycemic pregnancy. METHODS: The GLUT2 gene of 96 MM patients was amplified, sequenced and compared with the reference sequence (NM_000340). Variants previously unreported in the single nucleotide polymorphisms (SNP) database were considered novel. Allele frequencies of reported SNPs were compared with reference populations using Fisher's exact test. RESULTS: Analysis revealed three novel variants: a substitution in the core promoter region (c.-331c>t), a substitution (c.-182g>a) in the 5'-untranslated region, and a single base pair deletion (c.1441delT) in the coding sequences. Polymorphic alleles for 10 SNPs were also identified. Seven SNPs are significantly associated with MM in the Mexican American patients tested (p < 0.05) and two of the seven remained significant after Bonferroni correction. CONCLUSION: We identified three novel variants and seven SNPs associated with MM. The novel variants in the core promoter and in the 5'-untranslated region could affect GLUT2 mRNA transcription and stability and translation efficiency. The c.1441delT variant is predicted to alter the reading frame and prematurely terminate translation of the GLUT2 protein at the C-terminus, affecting GLUT2 protein function. Presence of GLUT2 variants may disrupt GLUT2 activity and influence MM susceptibility.
Tennis P, Chan KA, Curkendall SM
… +14 more, Li DK, Mines D, Peterson C, Andrews EB, Calingaert B, Chen HY, Deshpande G, Everage N, Holick CN, Meyer NM, Nkhoma ET, Quinn S, Rothman KJ, Esposito DB
Birth Defects Res A Clin Mol Teratol
· 2015 Apr · PMID 25776342
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BACKGROUND: We measured birth prevalence of major congenital malformations (MCMs) after topiramate use during pregnancy to screen for a possible signal of increased risk. METHODS: Using four healthcare databases, we iden...BACKGROUND: We measured birth prevalence of major congenital malformations (MCMs) after topiramate use during pregnancy to screen for a possible signal of increased risk. METHODS: Using four healthcare databases, we identified three cohorts of pregnant women: cohort 1, used topiramate during the first trimester; cohort 2, used topiramate or another antiepileptic drug previously but not during pregnancy; and cohort 3, were pregnant and did not use topiramate but had indications for use individually matched to those of users. Cohort 1 was compared with cohorts 2 and 3. MCMs were a code for any major congenital malformation dated within 30 days of the delivery date on the mother's claims or within 365 days after infant birth date, excluding a genetic or syndromic basis, and with procedure or healthcare usage consistent with the MCM diagnosis code in the 365 days after infant birth. RESULTS: Of the 10 specific common MCMs evaluated, 1 (conotruncal heart defects) had a prevalence ratio greater than 1.5 for both primary comparisons, and 4 (ventricular septal defect, atrial septal defect, hypospadias, coarctation of the aorta) had a prevalence ratio greater than 1.5 for one of the two comparisons. Following screening of organ systems with elevated MCMs, the prevalence ratio was greater than 1.5 for patent ductus arteriosus in both comparisons and for obstructive genitourinary defects in one comparison. CONCLUSION: To evaluate a large number of MCMs across many pregnancies, we used crude methods for detecting potential signals. Therefore, these results should be seen as potential signals, not causal.
Badura-Stronka M, Mróz D, Beighton P
… +4 more, Łukawiecki S, Wicher K, Latos-Bieleńska A, Kozłowski K
Birth Defects Res A Clin Mol Teratol
· 2015 Jun · PMID 25776145
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BACKGROUND: Lehmann et al., [2003, 2006] have documented two different substitutions at position 486 of the BMPR1B gene which resulted in a phenotype of brachydactyly A2 [MIM 112600] or brachydactyly C with symphalangism...BACKGROUND: Lehmann et al., [2003, 2006] have documented two different substitutions at position 486 of the BMPR1B gene which resulted in a phenotype of brachydactyly A2 [MIM 112600] or brachydactyly C with symphalangism [MIM 113100]. METHODS: In this article we report a family of Polish extraction with a novel mutation: c.1457G>T (R486L) which segregated with a complex brachydactyly. Clinical and radiological data are presented and details of previously reported patients with a pathogenic change of an amino acid at position 486 of the BMPR1B gene are summarized. CONCLUSION: Our data extends the previously known mutational and radiological spectrum associated with mutations in the BMPR1B gene and confirms the existence of a universal hotspot in the BMPR1B gene in this distinctive autosomal dominant brachydactyly disorder. It is of interest that an affected female in the Polish family had a severe congenital malformation of the venous system in addition to her digital anomalies. This observation raises the possibility of disturbance of embryonic angiogenesis by specific mutations in BMPR1B.
O'Leary LA, Ortiz L, Montgomery A
… +15 more, Fox DJ, Cunniff C, Ruttenber M, Breen A, Pettygrove S, Klumb D, Druschel C, Frías JL, Robinson LK, Bertrand J, Ferrara K, Kelly M, Gilboa SM, Meaney FJ, FASSNetII
Birth Defects Res A Clin Mol Teratol
· 2015 Mar · PMID 25761572
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Surveillance of fetal alcohol syndrome (FAS) is important for monitoring the effects of prenatal alcohol exposure and describing the public health burden of this preventable disorder. Building on the infrastructure of th...Surveillance of fetal alcohol syndrome (FAS) is important for monitoring the effects of prenatal alcohol exposure and describing the public health burden of this preventable disorder. Building on the infrastructure of the Fetal Alcohol Syndrome Surveillance Network (FASSNet, 1997-2002), in 2009 the Centers for Disease Control and Prevention awarded 5-year cooperative agreements to three states, Arizona, Colorado, and New York, to conduct population-based surveillance of FAS. The Fetal Alcohol Syndrome Surveillance Network II (FASSNetII, 2009-2014) developed a surveillance case definition based on three clinical criteria: characteristic facial features, central nervous system abnormalities, and growth deficiency. FASSNetII modified the FASSNet methods in three important ways: (1) estimation of a period prevalence rather than birth prevalence; (2) surveillance of FAS among school-age children (ages 7-9 years) to better document the central nervous system abnormalities that are not apparent at birth or during infancy; and (3) implementation of an expert clinical review of abstracted data for probable and confirmed cases classified through a computerized algorithm. FASSNetII abstracted data from multiple sources including birth records, medical records from child development centers or other specialty clinics, and administrative databases such as hospital discharge and Medicaid. One challenge of FASSNetII was its limited access to non-medical records. The FAS prevalence that could be estimated was that of the population identified through an encounter with the healthcare system. Clinical and public health programs that identify children affected by FAS provide critical information for targeting preventive, medical and educational services in this vulnerable population.
Bárcenas-Ibarra A, de la Cueva H, Rojas-Lleonart I
… +4 more, Abreu-Grobois FA, Lozano-Guzmán RI, Cuevas E, García-Gasca A
Birth Defects Res A Clin Mol Teratol
· 2015 Mar · PMID 25761253
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BACKGROUND: Congenital malformations in sea turtles have been considered sporadical. Research carried out in the Mexican Pacific revealed high levels of congenital malformations in the olive ridley, but little or no info...BACKGROUND: Congenital malformations in sea turtles have been considered sporadical. Research carried out in the Mexican Pacific revealed high levels of congenital malformations in the olive ridley, but little or no information is available for other species. We present results from analyses of external congenital malformations in olive ridley, green, and hawskbill sea turtles from Mexican rookeries on the Pacific coast and Gulf of Mexico. METHODS: We examined 150 green and hawksbill nests and 209 olive ridley nests during the 2010 and 2012 nesting seasons, respectively. Olive ridley eggs were transferred to a hatchery and incubated in styrofoam boxes. Nests from the other two species were left in situ. Number of eggs, live and dead hatchlings, and eggs with or without embryonic development were registered. Malformation frequency was evaluated with indices of prevalence and severity. RESULTS: Mortality levels, prevalence and severity were higher in olive ridley than in hawksbill and green sea turtles. Sixty-three types of congenital malformations were observed in embryos, and dead or live hatchlings. Of these, 38 are new reports; 35 for wild sea turtles, three for vertebrates. Thirty-one types were found in hawksbill, 23 in green, and 59 in olive ridley. The head region showed a higher number of malformation types. Malformation levels in the olive ridley were higher than previously reported. CONCLUSION: Olive ridleys seem more prone to the occurrence of congenital malformations than the other two species. Whether the observed malformation levels are normal or represent a health problem cannot be currently ascertained without long-term assessments.
McNeese ML, Selwyn BJ, Duong H
… +2 more, Canfield M, Waller DK
Birth Defects Res A Clin Mol Teratol
· 2015 Feb · PMID 25721953
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BACKGROUND: Previous studies observed that first birth is associated with an increased risk of some categories of birth defects. However, multiple statistical tests were conducted and it was unclear which of these associ...BACKGROUND: Previous studies observed that first birth is associated with an increased risk of some categories of birth defects. However, multiple statistical tests were conducted and it was unclear which of these associations would be replicated in a larger study. We used a large database to assess the association between maternal parity and 65 birth defects including birth defects that have not been previously studied. METHODS: Using data from the Texas Birth Defects Registry for years 1999-2009, the risk of a birth defect occurring in a first, third, or fourth or higher birth was compared to the risk of a birth defect occurring in a second birth. RESULTS: Women having their first birth had significantly increased odds of having an infant with 24 of 65 categories of birth defects when compared to women having their second birth. We also observed associations between first birth and an increased risk of five birth defects not previously reported (small penis, preaxial polydactyly, anomalies of the thoracic vertebrae, anomalies of the lumbar vertebrae, and sacroccygeal anomalies). Women having their third or fourth or higher birth had significantly increased odds of giving birth to infants with five of 65 birth defects when compared to second births. CONCLUSIONS: Our observations regarding the categories of birth defects that were associated with first births were highly consistent with observations from two previous studies. Research into biological, behavioral, and environmental factors that may increase the risk of specific birth defects among first births is needed to further explore these associations.
Birth Defects Res A Clin Mol Teratol
· 2015 Feb · PMID 25721952
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BACKGROUND: Little is known about population-based maternal, child, and system characteristics associated with high hospital resource use for children with orofacial clefts (OFC) in the US. METHODS: This was a statewide,...BACKGROUND: Little is known about population-based maternal, child, and system characteristics associated with high hospital resource use for children with orofacial clefts (OFC) in the US. METHODS: This was a statewide, population-based, retrospective observational study of children with OFC born between 1998 and 2006, identified by the Florida Birth Defects Registry whose records were linked with longitudinal hospital discharge records. We stratified the descriptive results by cleft type [cleft lip with cleft palate, cleft lip, and cleft palate] and by isolated versus nonisolated OFC (accompanied by other coded major birth defects). We used Poisson regression to analyze associations between selected characteristics and high hospital resource use (≥90th percentile of estimated hospitalized days and inpatient costs) for birth, postbirth, and total hospitalizations initiated before age 2 years. RESULTS: Our analysis included 2,129 children with OFC. Infants who were born low birth weight (<2500 grams) were significantly more likely to have high birth hospitalization costs for CLP (adjusted prevalence ratio: 1.6 [95% confidence interval: 1.0-2.7]), CL (adjusted prevalence ratio: 3.0 [95% confidence interval: 1.1-8.1]), and CP (adjusted prevalence ratio: 2.3 [95% confidence interval: 1.3-4.0]). Presence of multiple birth defects was significantly associated with a three- to eleven-fold and a three- to nine-fold increase in the prevalence of high costs and number of hospitalized days, respectively; at birth, postbirth before age 2 years and overall hospitalizations. CONCLUSION: Children with cleft palate had the greatest hospital resources use. Additionally, the presence of multiple birth defects contributed to greater inpatient days and costs for children with OFC.
Aggarwal D, Warmerdam B, Wyatt K
… +2 more, Ahmad S, Shaw GM
Birth Defects Res A Clin Mol Teratol
· 2015 Feb · PMID 25721951
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BACKGROUND: Approximately 6.3 million live births and fetal deaths occurred during the ascertainment period in the California Birth Defects Monitoring Program registry. American-Indian and non-Hispanic white women delive...BACKGROUND: Approximately 6.3 million live births and fetal deaths occurred during the ascertainment period in the California Birth Defects Monitoring Program registry. American-Indian and non-Hispanic white women delivered 40,268 and 2,044,118 births, respectively. While much information has been published about non-Hispanic white infants, little is known regarding the risks of birth defects among infants born to American-Indian women. METHODS: This study used data from the California Birth Defects Monitoring Program to explore risks of selected birth defects in offspring of American-Indian relative to non-Hispanic white women in California. The study population included all live births and fetal deaths 20 weeks or greater from 1983 to 2010. Prevalence ratios and corresponding 95% confidence intervals (CI) were computed using Poisson regression for 51 groupings of birth defects. RESULTS: Prevalence ratios were estimated for 51 groupings of birth defects. Of the 51, nine had statistically precise results ranging from 0.78 to 1.85. The eight groups with elevated risks for American-Indian births were reduction deformities of brain, anomalies of anterior segments, specified anomalies of ear, ostium secundum type atrial septal defect, specified anomalies of heart, anomalies of the aorta, anomalies of great veins, and cleft lip with cleft palate. CONCLUSION: Our results suggest that American-Indian women having babies in California may be at higher risk for eight birth defect phenotypes compared with non-Hispanic whites. Further research is needed to determine whether these risks are observed among other populations of American-Indian women or when adjusted for potential covariates.
Birth Defects Res A Clin Mol Teratol
· 2015 Feb · PMID 25711386
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BACKGROUND: The etiology of Langerhans cell histiocytosis (LCH), a rare cancer-like disorder of the immune system, is largely unknown although a genetic component has been suggested based on familial cases, and reports o...BACKGROUND: The etiology of Langerhans cell histiocytosis (LCH), a rare cancer-like disorder of the immune system, is largely unknown although a genetic component has been suggested based on familial cases, and reports of chromosome instability and genetic mutation. Associations between various cancers and congenital anomalies have been reported and although congenital anomalies have been noted in children with LCH only one study to date has reported their frequency. An association between congenital anomalies and LCH may suggest a common etiological pathway, in particular, a genetic pathway. METHODS: Data from two coterminous registries in the same geographic region were used. All cases of LCH on the Northern Region Young Persons Malignant Disease Register diagnosed between 1985 and 2010 were cross-matched with live-born cases of congenital anomaly registered by the Northern Congenital Abnormality Survey. RESULTS: A total of 819,890 children and young people were born during 1985 to 2008. Of these, 13,799 (1.7%) had a congenital anomaly and 39 (0.005%) were diagnosed with LCH. Three LCH cases were identified among those with congenital anomalies, all three of whom had congenital heart disease. The relative risk of LCH for those with a congenital anomaly, compared with those without, was 4.87 (95% confidence interval, 1.50-15.81; p = 0.03). CONCLUSION: LCH was associated with congenital anomaly in a small but statistically significant number of patients, raising the possibility of a common genetic pathway in some cases.
Heisey AS, Bell EM, Herdt-Losavio ML
… +1 more, Druschel C
Birth Defects Res A Clin Mol Teratol
· 2015 Feb · PMID 25684703
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BACKGROUND: As assisted reproductive technology (ART) becomes more common, it is important to understand the associated risks. The objective of this study was to determine if congenital malformations are associated with...BACKGROUND: As assisted reproductive technology (ART) becomes more common, it is important to understand the associated risks. The objective of this study was to determine if congenital malformations are associated with ART or other fertility treatments in New York. METHODS: In a retrospective cohort study of all live births in upstate New York from 1997 to 2005, exposure was defined using ART or other fertility treatments as noted on birth certificates. Outcomes were assessed from the New York State Congenital Malformations Registry. Specific malformations were examined to determine if there is elevated risk for exposed singleton infants compared with infants conceived naturally. RESULTS: The study included 7120 in the ART group, 11,890 in the other fertility treatments group and 1,118,162 in the comparison group. The relative risk for a congenital malformation was 1.43 (95% CI 1.19-1.72) for singleton infants conceived through ART compared with singleton infants conceived naturally. The specific defects associated with ART were patent ductus arteriosus, hypospadias, and obstructive defect in the renal pelvis and ureter, while spina bifida, other specific anomalies of the spinal cord, atresia or stenosis of the pulmonary valve, hypospadias, and obstructive defects of the renal pelvis and ureter were associated with other fertility treatment. CONCLUSION: Assisted reproductive technology is associated with a slight excess risk of birth defects. The specific congenital malformations with elevated risks for singleton infants vary depending on the exposure. Further research is necessary to understand the mechanism related to the increase in risk.
Skarsgard ED, Meaney C, Bassil K
… +4 more, Brindle M, Arbour L, Moineddin R, Canadian Pediatric Surgery Network (CAPSNet)
Birth Defects Res A Clin Mol Teratol
· 2015 Feb · PMID 25684659
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BACKGROUND: Gastroschisis is a congenital abdominal wall defect that occurs in one per 2200 pregnancies. Birth defect surveillance in Canada has shown that the prevalence of gastroschisis has increased threefold over the...BACKGROUND: Gastroschisis is a congenital abdominal wall defect that occurs in one per 2200 pregnancies. Birth defect surveillance in Canada has shown that the prevalence of gastroschisis has increased threefold over the past 10 years. The purpose of this study was to compare maternal exposures data from a national gastroschisis registry with pregnancy exposures from vital statistics to understand maternal risk factor associations with the occurrence of gastroschisis. METHODS: Using common definitions, pregnancy cohorts were developed from two databases. The Canadian Pediatric Surgery Network database, a population-based dataset was used to record maternal exposures for women who experienced a gastroschisis pregnancy, while a contemporaneous, geographically cross-sectional "control" cohort of pregnant women and their exposures was developed from Canadian Community Health Survey data. Groups comparison of maternal risk factors was performed using univariate and multivariate logistic generalized estimating equation techniques. RESULTS: A total of 692 gastroschisis pregnancies (from Canadian Pediatric Surgery Network) and 4708 pregnancies from Canadian Community Health Survey were compared. Younger maternal age (odds ratio, 0.85; 95% confidence interval, 0.83-0.87; p < 0.0001), smoking (odds ratio, 2.86; 95% confidence interval, 2.22-3.66; p < 0.0001), a history of pregestational or gestational diabetes (odds ratio, 2.81; 95% confidence interval, 1.42-5.5; p = 0.0031), and use of medication to treat depression (odds ratio, 4.4; 95% confidence interval, 1.38-11.8; p = 0.011) emerged as significant associations with gastroschisis pregnancies. CONCLUSION: Gastroschisis in Canada is associated with maternal risk factors, some of which are modifiable. Further studies into sociodemographic birth defect risk are necessary to allow targeted improvements in perinatal health service delivery and health policy.
Jaiswal SK, Sukla KK, Kumari N
… +3 more, Lakhotia AR, Kumar A, Rai AK
Birth Defects Res A Clin Mol Teratol
· 2015 Apr · PMID 25656965
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BACKGROUND: Epigenetic changes leading to improper methylation of the pericentromeric region of chromosome 21 may contribute to the nondisjunction of this chromosome. Polymorphisms in the DNA Methyltransferase 3B (DNMT3B...BACKGROUND: Epigenetic changes leading to improper methylation of the pericentromeric region of chromosome 21 may contribute to the nondisjunction of this chromosome. Polymorphisms in the DNA Methyltransferase 3B (DNMT3B) gene, one of the crucial gene of the folate metabolism, affects the activity of the enzyme and increases the susceptibility of nondisjunction in mothers of Down syndrome children (MDS). METHODS: Considering this hypothesis we investigated the association of single nucleotide polymorphisms in the promoter region of the DNMT3B gene (rs1569686 -579G>T; rs2424913 -149C>T) with a predisposition of mothers to deliver a Down syndrome (DS) child. The study was performed on DNA samples from 150 MDS and 172 control mothers. Transmission disequilibrium tests were performed on 103 DS trio families. Genotyping was done using a polymerase chain reaction-restriction fragment length polymorphism method. RESULTS: With respect to the single nucleotide polymorphisms studied, no significant difference was observed in the genotypes and alleles frequency distributions between MDS and control mothers. The frequency of the DNMT3B-579G allele was, respectively, 0.34 in MDS and 0.33 in control mothers whereas the frequency of the DNMT3B-149C allele was respectively 0.31 in MDS and 0.26 in control mothers. No significant deviation in genotypic combinations as well as in transmission disequilibrium tests analysis was observed. However, a strong linkage disequilibrium was observed with significant differences in the distribution of G-T and G-C haplotypes among case and control mothers. CONCLUSION: Although the above studied polymorphisms of DNMT3B may not be an independent risk factor it might be possible that certain allelic combinations (G-T) are. This finding suggests that DNMT3B might be a maternal risk factor for DS in our Indian cohort. Replication studies are required to confirm these findings.
Molineaux AC, Maier JA, Schecker T
… +1 more, Sears KE
Birth Defects Res A Clin Mol Teratol
· 2015 Mar · PMID 25656823
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BACKGROUND: Retinoic acid (RA) is a vitamin A derivative. Exposure to exogenous RA generates congenital limb malformations (CLMs) in species from frogs to humans. These CLMs include but are not limited to oligodactyly an...BACKGROUND: Retinoic acid (RA) is a vitamin A derivative. Exposure to exogenous RA generates congenital limb malformations (CLMs) in species from frogs to humans. These CLMs include but are not limited to oligodactyly and long-bone hypoplasia. The processes by which exogenous RA induces CLMs in mammals have been best studied in mouse, but as of yet remain unresolved. METHODS: We investigated the impact of exogenous RA on the cellular and molecular development of the limbs of a nonrodent model mammal, the opossum Monodelphis domestica. Opossums exposed to exogenous retinoic acid display CLMs including oligodactly, and results are consistent with opossum development being more susceptible to RA-induced disruptions than mouse development. RESULTS: Exposure of developing opossums to exogenous RA leads to an increase in cell death in the limb mesenchyme that is most pronounced in the zone of polarizing activity, and a reduction in cell proliferation throughout the limb mesenchyme. Exogenous RA also disrupts the expression of Shh in the zone of polarizing activity, and Fgf8 in the apical ectodermal ridge, and other genes with roles in the regulation of limb development and cell death. CONCLUSION: Results are consistent with RA inducing CLMs in opossum limbs by disrupting the functions of the apical ectodermal ridge and zone of polarizing activity, and driving an increase in cell death and reduction of cell proliferation in the mesenchyme of the developing limb.
Lamm SH, Li J, Robbins SA
… +3 more, Dissen E, Chen R, Feinleib M
Birth Defects Res A Clin Mol Teratol
· 2015 Feb · PMID 25388330
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BACKGROUND: Pooled 1996 to 2003 birth certificate data for four central states in Appalachia indicated higher rates of infants with birth defects born to residents of counties with mountain-top mining (MTM) than born to...BACKGROUND: Pooled 1996 to 2003 birth certificate data for four central states in Appalachia indicated higher rates of infants with birth defects born to residents of counties with mountain-top mining (MTM) than born to residents of non-mining-counties (Ahern 2011). However, those analyses did not consider sources of uncertainty such as unbalanced distributions or quality of data. Quality issues have been a continuing problem with birth certificate analyses. We used 1990 to 2009 live birth certificate data for West Virginia to reassess this hypothesis. METHODS: Forty-four hospitals contributed 98% of the MTM-county births and 95% of the non-mining-county births, of which six had more than 1000 births from both MTM and nonmining counties. Adjusted and stratified prevalence rate ratios (PRRs) were computed both by using Poisson regression and Mantel-Haenszel analysis. RESULTS: Unbalanced distribution of hospital births was observed by mining groups. The prevalence rate of infants with reported birth defects, higher in MTM-counties (0.021) than in non-mining-counties (0.015), yielded a significant crude PRR (cPRR = 1.43; 95% confidence interval [CI] = 1.36-1.52) but a nonsignificant hospital-adjusted PRR (adjPRR = 1.08; 95% CI = 0.97-1.20; p = 0.16) for the 44 hospitals. So did the six hospital data analysis ([cPRR = 2.39; 95% CI = 2.15-2.65] and [adjPRR = 1.01; 95% CI, 0.89-1.14; p = 0.87]). CONCLUSION: No increased risk of birth defects was observed for births from MTM-counties after adjustment for, or stratification by, hospital of birth. These results have consistently demonstrated that the reported association between birth defect rates and MTM coal mining was a consequence of data heterogeneity. The data do not demonstrate evidence of a "Mountain-top Mining" effect on the prevalence of infants with reported birth defects in WV.