PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Neural Tube Defects”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 973 records · Page 54Linked to original sources
PubMed2006

Transitional and health issues of adults with neural tube defects.

PURPOSE: To examine past, current, and future developmental and health care issues and concerns of Caucasian, African American, and Mexican American adults, aged 20 to 75 years, with neural tube defects (NTDs). DESIGN: Naturalistic inquiry. METHODS: A semi-structured interview was used to obtain information from 16 Caucasian, 11 African American, and 15 Mexican American adults. FINDINGS: Three themes identified in the analysis were uncertainty about the future, access to health care and information, and advocacy. CONCLUSIONS: Documenting the adult trajectories of chronic childhood conditions, such as NTDs, is important. Although much is known about such conditions in childhood, additional knowledge about health and developmental concerns across the lifespan enhances provision of appropriate anticipatory guidance and health care.

Activities of Daily Living↗
PubMed1999

Amniotic fluid amino and nucleic acid in normal and neural tube defect pregnancies. A comparison.

OBJECTIVE: To explore the relationship between fetal amino acids (AAs), which are the components of structural proteins and nucleic acids, and the changes associated with neural tube defects (NTD). STUDY DESIGN: Ten weekly amniotic fluid (AF) samples from normal pregnancies (non-NTD) and 10 from NTD pregnancies between 16 and 20 weeks' gestational age were analyzed for AAs, and the weekly average for the non-NTD and NTD groups was determined. The group mean levels were compared by ANOVA. RESULTS: The weekly group mean levels of methionine, serine and aspartic acid were significantly lower than the weekly group mean levels of the other AAs. The group mean levels of methionine were significantly lower for NTD than for non-NTD pregnancies. CONCLUSION: The mean methionine level in NTD pregnancies was the only AA alteration in NTD. Although the AF levels of the non-NTD pregnancies showed that the levels of serine, aspartic acid and methionine were 3- to 19-fold lower than those of the other AAs, only methionine is essential. Consequently, methionine is rate limiting with respect to the role of structural proteins and nucleic acids in the fetus.

Amino Acids↗
PubMed1994

Exclusion mapping of the gene for X-linked neural tube defects in an Icelandic family.

Various polymorphic markers with a random distribution along the X chromosome were used in a linkage analysis performed on a family with apparently X-linked recessive inheritance of neural tube defects (NTD). The lod score values were used to generate an exclusion map of the X chromosome; this showed that the responsible gene was probably not located in the middle part of Xp or in the distal region of Xq. A further refining of these results was achieved by haplotype analysis, which indicated that the gene for X-linked NTD was located either within Xp21.1-pter, distal from the DMD locus, or in the region Xq12-q24 between DXS106 and DXS424. Multipoint linkage analysis revealed that the likelihood for gene location is highest for the region on Xp. The region Xq26-q28, which has syntenic homology with the segment of the murine X chromosome carrying the locus for 'bent tail' (Bn), a mouse model for X-linked NTD, is excluded as the location for the gene underlying X-linked NTD in the present family. Thus, the human homologue of the Bn gene and the present defective gene are not identical, suggesting that more than one gene on the X chromosome plays a role in the development of the neural tube.

Chromosome Mapping↗
PubMed2006

Neural tube defects and folate pathway genes: family-based association tests of gene-gene and gene-environment interactions.

BACKGROUND: Folate metabolism pathway genes have been examined for association with neural tube defects (NTDs) because folic acid supplementation reduces the risk of this debilitating birth defect. Most studies addressed these genes individually, often with different populations providing conflicting results. OBJECTIVES: Our study evaluates several folate pathway genes for association with human NTDs, incorporating an environmental cofactor: maternal folate supplementation. METHODS: In 304 Caucasian American NTD families with myelomeningocele or anencephaly, we examined 28 polymorphisms in 11 genes: folate receptor 1, folate receptor 2, solute carrier family 19 member 1, transcobalamin II, methylenetetrahydrofolate dehydrogenase 1, serine hydroxymethyl-transferase 1, 5,10-methylenetetrahydrofolate reductase (MTHFR), 5-methyltetrahydrofolate-homo-cysteine methyltransferase, 5-methyltetrahydrofolate-homocysteine methyltransferase reductase, betaine-homocysteine methyltransferase (BHMT), and cystathionine-beta-synthase. RESULTS: Only single nucleotide polymorphisms (SNPs) in BHMT were significantly associated in the overall data set; this significance was strongest when mothers took folate-containing nutritional supplements before conception. The BHMT SNP rs3733890 was more significant when the data were stratified by preferential transmission of the MTHFR rs1801133 thermolabile T allele from parent to offspring. Other SNPs in folate pathway genes were marginally significant in some analyses when stratified by maternal supplementation, MTHFR, or BHMT allele transmission. CONCLUSIONS: BHMT rs3733890 is significantly associated in our data set, whereas MTHFR rs1801133 is not a major risk factor. Further investigation of folate and methionine cycle genes will require extensive SNP genotyping and/or resequencing to identify novel variants, inclusion of environmental factors, and investigation of gene-gene interactions in large data sets.

Alleles↗
PubMed1992

Nutrient levels in amniotic fluid from women with normal and neural tube defect pregnancies.

We analyzed nutrient levels in amniotic fluid obtained during the second trimester of normal, uncomplicated pregnancies from 221 women who delivered apparently healthy infants and from 8 with neural tube defect (NTD) pregnancies. Folate was measured by microbiological assay, vitamin B12 by a radiobinding method, and zinc, copper and iron by atomic absorption spectrophotometry. We found that the mean amniotic fluid nutrient levels of normal pregnancies were 24.7 nmol/l for folate, 600 pmol/l for vitamin B12, and 1.7, 1.9, and 9.0 mumol/l for zinc, copper and iron, respectively. Amniotic fluid folate, zinc, copper and iron levels of NTD pregnancies were similar to those found during normal pregnancy, however, vitamin B12 levels were markedly lower than those of normal pregnancies.

Adolescent↗
PubMed1989

Maternal zinc and selenium status in pregnancies with a neural tube defect or elevated plasma alpha-fetoprotein.

Zinc and selenium status was assessed in 30 non-pregnant women, 69 women during normal pregnancy, six with a fetus with a neural tube defect (NTD) and 16 who had a raised plasma alpha-fetoprotein (AFP) but no detectable fetal abnormality. Plasma zinc and selenium concentrations were significantly reduced in the second trimester of normal pregnancy compared with non-pregnant levels. A significant decrease in concentrations of zinc in plasma and selenium in plasma and leucocytes was observed in women in the third trimester compared with women in the second trimester. Women with a fetal NTD and women with an unexplained elevation of plasma AFP had significantly lower leucocyte concentrations of zinc and of selenium. Mean values for plasma zinc, plasma and erythrocyte selenium, and for the activity of glutathione peroxidase in whole blood did not differ from those for normal pregnancy.

Erythrocytes↗
PubMed1994

Periconceptional folate and neural tube defect.

The US Public Health Service recommends that all women in the United States who might possibly become pregnant should consume 0.4 mg folic acid/d to lower the incidence of neural tube defect (NTD). This paper reviews the bases for this recommendation: controlled trials of periconceptional folate, observational studies of folate supplementation, studies relating dietary folate to NTD, a trial of dietary education aimed at lowering the rate of NTD, and studies of the relationship to NTD of serum and red blood cell folate concentrations. It remains unclear that trials to prevent recurrent NTD apply directly to occurrent NTD, and the minimum necessary dose of folate is unknown. Given the potential dangers of high levels of folate in the general diet, particularly the masking of the hematologic effects of vitamin B-12 deficiency in elderly persons, with the consequent possibility of vitamin B-12 deficiency presenting as severe, irreversible neurologic disease, it is suggested that, until the impact of increasing the general folate level of the diet is better understood, tablet supplementation of folate to women of child-bearing age is preferable as an interim measure to increased food fortification.

Diet↗
PubMed1999

Similarities in the epidemiology of neural tube defects and coronary heart disease: is homocysteine the missing link?

It is hypothesised that a single aetiological pathway could explain both the strong ecological association between the birth prevalence of neural tube defects (NTD) and coronary heart disease (CHD) mortality and the potential efficacy of dietary measures, especially increased folic acid intake, in their prevention. The epidemiological similarities between NTD and CHD are strong and consistent suggesting that the relation is real rather than artefactual. It is suggested that this epidemiological association reflects a shared aetiology arising from the role of disturbed homocysteine metabolism in the pathogenesis of both conditions. Current public health measures designed to increase the intake of periconceptional folic acid in women, reinforced by a broadening of this policy to target both sexes throughout life, will (if successful) result in a reduction in both the birth prevalence of NTD and the incidence of CHD, although not necessarily contemporaneously. If disordered homocysteine metabolism is the cause of both NTD and CHD, this has implications for future research and preventive strategies for these serious and often lethal diseases.

Coronary Disease↗
PubMed2002

Protein kinase A deficiency causes axially localized neural tube defects in mice.

We have studied the function of protein kinase A (PKA) during embryonic development using a PKA-deficient mouse that retains only one functional catalytic subunit allele, either Calpha or Cbeta, of PKA. The reduced PKA activity results in neural tube defects that are specifically localized posterior to the forelimb buds and lead to spina bifida. The affected neural tube has closed appropriately but exhibits an enlarged lumen and abnormal neuroepithelium. Decreased PKA activity causes dorsal expansion of Sonic hedgehog signal response in the thoracic to sacral regions correlating with the regions of morphological abnormalities. Other regions of the neural tube appear normal. The regional sensitivity to changes in PKA activity indicates that downstream signaling pathways differ along the anterior-posterior axis and suggests a functional role for PKA activation in neural tube development.

Alleles↗
PubMed2005

Routine ultrasonography compared with maternal serum alpha-fetoprotein for neural tube defect screening.

OBJECTIVE: This study was done to estimate the value of prenatal maternal serum alpha-fetoprotein (MSAFP) screening compared with that of routine ultrasonography in the diagnosis of neural tube defects (NTDs). METHODS: An integrated database was used retrospectively to identify cases of NTDs among 219,000 consecutive pregnancy outcomes observed during a 7-year period at 40 Kaiser Permanente facilities in Northern California. We specifically examined types of NTD and the tests used to diagnose cases. RESULTS: We identified 189 NTD cases, 102 of which had received MSAFP screening. Results of MSAFP testing were negative in 25 (25%) of these 102 cases. Without other testing, these 25 NTD diagnoses would have been missed. These included 15 (38%) of the 40 spina bifida cases screened, 6 (67%) of the 9 encephalocele cases screened, and 4 (8%) of the 53 anencephaly cases screened. Of the 186 NTD cases diagnosed prenatally, 115 (62%) were initially detected by routine ultrasonography administered during the second trimester without knowledge of MSAFP values; 69 (37%) were diagnosed by targeted ultrasonography after MSAFP screening indicated a higher risk for NTD; and 2 (1%) were diagnosed by pathology examination after miscarriage. CONCLUSION: Compared with MSAFP performed alone for screening, routine second-trimester ultrasonography was more likely to discover an NTD.

Adolescent↗
PubMed1997

Is the common 677C-->T mutation in the methylenetetrahydrofolate reductase gene a risk factor for neural tube defects? A meta-analysis.

The common 677C-->T mutation (+) in the 5,10-methylenetetrahydrofolate reductase gene, resulting in decreased activity of the enzyme, has been associated with spina bifida neural tube defects (NTD). We combined all known Dutch control groups, a total of 1273 individuals, and found a prevalence of the 677C-->T mutation of 8.4%. When compared with the frequencies in 55 SB patients and to mothers with a child with SB their parents, this gave an OR of 1.9 [95% CI 1.1-3.3] for mothers and an OR of 1.5 [95% CI 0.74-3.1] for patients. The frequency of this mutation and its associated risk for NTD may be population-dependent. However, the frequencies of the 677C-->T mutation in different national and international control groups are almost all in the same range. We therefore combined the observed frequencies of the 677C-->T mutation in all reported studies. The mutation was present in 9.2% of controls, resulting in ORs for all reported NTD patients and their parents of: 1.7 [95% CI: 1.1-2.6]; 1.8 [95% CI: 1.1-3.1] and 1.9 [95% CI: 1.3-2.8] for mothers (combined prevalence 14.5%), fathers (combined prevalence 15.5%) and NTD patients (combined prevalence 16.4%), respectively, vs. all international controls. This meta-analysis confirms that the 677C-->T mutation is a genetic risk factor for NTD.

Female↗
PubMed1996

Transferrin and its receptor in the development of genetically determined neural tube defects in the mouse embryo.

The iron-binding growth factor transferrin is taken up and localised in the hindgut of midgestation mouse embryos. We investigated whether the distribution of transferrin may be disturbed in mutant curly tail embryos, a proportion of which exhibit a cell proliferation defect affecting the hindgut endoderm, as part of the pathogenetic sequence leading to development of neural tube defects. Immunostaining revealed a reduction in the binding and/or uptake of transferrin by hindgut epithelial cells in affected curly tail embryos compared with their unaffected littermates. There was no apparent difference between the two embryo types, however, in the distribution or level of expression of the transferrin receptor. The receptor is expressed specifically in the hindgut endoderm of the 10.5-day embryo, although its mRNA is present in all tissues of the posterior neuropore region, suggesting posttranscriptional control of gene expression. These findings may indicate a role for transferrin binding and/or uptake in the regulation of cell proliferation in the hindgut endoderm, with a defect in this process in the curly tail mutant. However, an alternative explanation is suggested by our finding that transferrin immunostaining is more intense in the hindgut of unaffected curly tail embryos than in nonmutant CBA/Ca and CD-1 embryos. Thus, mutant embryos may increase their uptake of transferrin in an attempt to compensate for defective cell proliferation in the hindgut resulting from a defect in another pathway. Only a proportion of embryos are able to mount this compensatory response leading to the observed partial penetrance of developmental defects in the curly tail mutant mouse.

Animals↗
PubMed1980

Concanavalin A reactivity pattern of human amniotic fluid AFP examined by crossed affino-immunoelectrophoresis. A definite test for neural tube defect?

The percentage of alpha-fetoprotein (AFP) not reacting with concanavalin A (con A) was determined by crossed line affino-immunoelectrophoresis in amniotic fluid from 25 pregnancies with neural tube defects (NTD) and other fetal abnormalities giving rise to elevated AFP levels, and from 128 pregnancies with normal outcome. The percentage of con A non-reactive AFP is significantly lower in the presence of fetal abnormalities (mean 3.4%, range: 0.0-6.3, n = 25), compared to the percentage found in normal pregnancies (mean 17.2%, range: 6.6-35.8%, n = 128). In amniotic fluid samples from normal pregnancies, the percentage of con A non-reactive AFP in 84 cases with total AFP levels lying within the 95% reference interval was not significantly different from the percentage found in 44 cases with levels above the 95% reference interval. The percentage of non-reactive AFP in fetal serum and cerebrospinal fluid was of the same magnitude as found in amniotic fluids of pregnancies with fetal abnormalities. It is concluded that analysis of the percentage of con A non-reactive AFP by crossed line affino-immunoelectrophoresis is a simple, reliable and apparently diagnostic test for NTD and other abnormalities with leakage of fetal serum or cerebrospinal fluid into the amniotic fluid. The test should therefore be used in all cases with only marginally elevated AFP levels, so false positives may be avoided.

Amniotic Fluid↗
PubMed1986

[Determination of maternal serum alpha fetoprotein with a Polish AFP radioimmunoassay--a suitable screening method for neural tube defects?].

230 double determinations of maternal serum-alpha-fetoprotein have been made using a Polish AFP-RIA. On this basis the applicability of this method as a screening for neural tube defects has been proved. An additional comparison with a French RIA and an enzymimmunoassay (EIA) from the Serum-Werke Dessau confirmed an equal accuracy. There were three pathological increased values of AFP. In one case an anencephalus was found and in the other a spina bifida. In the third case the value was normal at the control examination. A general AFP screening in all pregnant women is recommended.

Female↗
PubMedDate not supplied

Incidence of neural tube defects in the least-developed area of India: a population-based study.

Hospital-based records from major cities of India, where roughly a quarter of the population resides, identified the frequency of neural tube defects (NTDs) as ranging from 3.9 to 8.8 per 1000 births, but the incidence in rural areas is unknown. We did a population-based door-to-door survey of mothers living in remote clusters of villages in Balrampur District in Uttar Pradesh, a region ranked as the least-developed area in India. The data showed that the incidence of NTDs was 6.57-8.21 per 1000 livebirths, which is among the highest worldwide. India's Ministry of Health needs to produce a strategy to reduce the incidence of such defects.

Female↗
PubMed2003

Neural tube defects associated with maternal periconceptional dietary intake of simple sugars and glycemic index.

BACKGROUND: Maternal diabetes, prepregnancy obesity, hyperinsulinemia, and intakes of sweets have been associated with increased risks of neural tube defects (NTDs). The interdependence of these factors suggests a common pathogenesis via altered glycemic control and insulin demand. OBJECTIVE: We investigated whether maternal periconceptional dietary intakes of sucrose, glucose, fructose, and foods with higher glycemic index values influence the risk of having NTD-affected pregnancies. DESIGN: In a population-based case-control study, all hospitals in 55 of the 58 counties in California participated. In-person interviews were conducted with the mothers of 454 NTD cases (including fetuses and infants who were electively terminated, stillborn, or born alive) and with the mothers of 462 nonmalformed controls within an average of 5 mo from the term delivery date. The risk of having an NTD-affected pregnancy was the main outcome measure. RESULTS: Risks of having an NTD-affected pregnancy were not substantially elevated in relation to periconceptional intakes of glucose or fructose. Elevated risks of approximately 2-fold were observed for higher intakes of sucrose and foods with higher glycemic index values. Elevated risks were observed for high sucrose intake irrespective of whether adjustment was made for other covariates such as maternal folic acid intake. For higher glycemic index values, adjusted elevated risks of > or = 4-fold were observed in women whose body mass index (in kg/m(2)) was > 29. CONCLUSION: Our observed associations support observations that potential problems in glucose control are associated with NTD risk even among nondiabetic women.

Adult↗
PubMed1998

A second common mutation in the methylenetetrahydrofolate reductase gene: an additional risk factor for neural-tube defects?

Recently, we showed that homozygosity for the common 677(C-->T) mutation in the methylenetetrahydrofolate reductase (MTHFR) gene, causing thermolability of the enzyme, is a risk factor for neural-tube defects (NTDs). We now report on another mutation in the same gene, the 1298(A-->C) mutation, which changes a glutamate into an alanine residue. This mutation destroys an MboII recognition site and has an allele frequency of .33. This 1298(A-->C) mutation results in decreased MTHFR activity (one-way analysis of variance [ANOVA] P < .0001), which is more pronounced in the homozygous than heterozygous state. Neither the homozygous nor the heterozygous state is associated with higher plasma homocysteine (Hcy) or a lower plasma folate concentration-phenomena that are evident with homozygosity for the 677(C-->T) mutation. However, there appears to be an interaction between these two common mutations. When compared with heterozygosity for either the 677(C-->T) or 1298(A-->C) mutations, the combined heterozygosity for the 1298(A-->C) and 677(C-->T) mutations was associated with reduced MTHFR specific activity (ANOVA P < .0001), higher Hcy, and decreased plasma folate levels (ANOVA P <.03). Thus, combined heterozygosity for both MTHFR mutations results in similar features as observed in homozygotes for the 677(C-->T) mutation. This combined heterozygosity was observed in 28% (n =86) of the NTD patients compared with 20% (n =403) among controls, resulting in an odds ratio of 2.04 (95% confidence interval: .9-4.7). These data suggest that the combined heterozygosity for the two MTHFR common mutations accounts for a proportion of folate-related NTDs, which is not explained by homozygosity for the 677(C-->T) mutation, and can be an additional genetic risk factor for NTDs.

Adenine↗