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PubMed1992

Maternal zinc and fetal neural tube defects.

Among the factors implicated in the heterogeneous etiology of neural tube defects (NTDs) is the trace element zinc (Zn). In a case-control study, we collected midtrimester maternal toenail samples for multiple trace element analyses, including Zn, which were assayed by neutron activation analysis. We studied 17 women with NTD offspring and 1,787 controls. The crude OR for NTD comparing Zn values greater than normal range to normal Zn values was 3.2 (95% CI 1.1,9.7). These results were not materially affected when adjustment was made for folic acid supplementation. An overall increased risk for NTD associated with increasing toenail Zn was also evident. A matched subset of 17 cases and 73 controls yielded a crude OR of 3.1 (95% CI 0.9,10.3) when cases with elevated Zn (greater than or equal to 120 ppm) were compared to those with normal Zn. Matched analyses controlling for folic acid supplements, family history of NTD, assay batch, age of mother and year of delivery yielded an OR of 5.0 (95% CI 1.1,21.6). This study reveals an association between increased toenail Zn in the second trimester of pregnancy and the risk of having a child with an NTD. Whether Zn sequestration has resulted in relative Zn deficiency at the site of neural tube closure remains uncertain.

Case-Control Studies↗
PubMed2002

The role of maternal reproductive history in the aetiology of neural tube defects.

The contribution of environmental factors to the aetiology of neural tube defects (NTD) has been stressed over recent years and many different risk factors have been proposed. We evaluated the reproductive history of 113 NTD cases to investigate the possible role of maternal age, gestational age, sex, parity and previous pregnancy. Our results show that parity and previous spontaneous abortion can be considered as risk factors for NTD and that an accurate evaluation of reproductive history can be useful for genetic counselling. The known benefits of periconceptional intervention in reducing the incidence of NTD in high risk populations, together with our results, means that mothers with a positive reproductive history for spontaneous abortion and for multiparity are ideal subjects for folic acid periconceptional management.

Abortion, Spontaneous↗
PubMed1981

Recurrence risks for neural tube defects in a genetic counseling clinic population.

The recurrence of neural tube defects (NTD) in the sib following the index case of all patients who consulted the South-East Thames Regional Health Authority Genetics Centre in the period 1972 to mid-1979 was calculated. A total of 1037 consecutive patients was studied, of whom 958 (93%) were traced. The overall recurrence was 3.44% (1 in 29). However, if the index case was the first affected child in the family, the recurrence in the next sib was 3.15% (1 in 32), and if it was the second affected child, the recurrence was 11.76% (1 in 9). These figures give an indication of the actual recurrence among the 'selected' population who consult a genetic advice centre, and are somewhat, but not significantly, different from figures for the general NTD population, which have been derived from studies of whole families.

Genetic Counseling↗
PubMed1986

A chromosome marker for the early detection of mouse embryos carrying the neural tube defect mutation splotch.

A major problem in the study of neural tube defects caused by the splotch (Sp) gene in the mouse has been the identification of gene carriers or potentially affected embryos at an early stage of development, since the gene's effects become visible only late in gestation or after birth. To aid in the identification of Sp carriers, we have developed a technique using a Robertsonian translocation as a marker for this gene. The accuracy of identification is reduced by crossing-over between the Sp locus and the centromere but, because of crossover suppression in the particular cross used, there was only 23.2% recombination compared with the known map distance of 36%. Paternal age had no effect on the frequency of recombination, but individual males differed significantly in the degree of crossover suppression.

Animals↗
PubMed1987

The natural history of vesicoureteric reflux in children with neuropathic bladder and open neural tube defects.

Vesicoureteric reflux in children with neuropathic bladder and open neural tube defects has been reviewed to determine its natural history. In 78%, reflux was identified during the first 2 years, emphasising the importance of investigation in the neonatal period and at regular intervals thereafter. Deterioration occurred in 67%. Those most likely to deteriorate had a flaccid detrusor and bilateral reflux, which was grade 4 or greater at the time of diagnosis. Only 24% remained unchanged and in only 9% did reflux resolve spontaneously. Many patients were treated by continuous or intermittent catheterisation, or by surgical procedures to reduce outflow obstruction, but with disappointing results. Surgical intervention for deteriorating upper tracts was usually late and involved extensive procedures such as nephroureterectomy or urinary diversion. The results suggest that treatment should be aimed primarily at restoration of the anti-reflux function of the vesicoureteric junction. Using endoscopic subureteric Teflon injection (STING) at an early stage, especially in the at risk group, it should be possible to avoid ongoing renal damage and more extensive, salvage surgery at a later date.

Adolescent↗
PubMed1978

Maternal plasma alpha-fetoprotein screening for fetal neural tube defects.

Maternal plasma alpha-fetoprotein (AFP) screening for fetal neural tube defects (NTD) was used as a part of routine antenatal care in three hospitals over a 26 month period. Blood samples were obtained for plasma AFP measurement at 15 to 20 weeks gestation from 6377 women, representing 79 per cent of antenatal bookings. The outcome of pregnancy was ascertained in 96 per cent of patients: 13 cases of anencephaly and 7 of open spina bifida were detected by plasma screening and a further 3 cases of open NTD through the mother's previous medical history and amniotic fluid determination. Four fetuses with open NTDs and four with closed NTDS were not detected by plasma AFP measurement and the detection efficiency for open NTDs was thus 83 per cent. Integration of screening into the existing pattern of antenatal care required only minor alterations in clinic schedules. Some extra time was needed for explanation of the objectives of the study, for ultrasound examination and for amniocentesis. Eight patients declined the offer of a plasma test, while only one refused an amniocentesis.

Amniotic Fluid↗
PubMed1999

[Difficulties of the methods for studying environmental exposure and neural tube defects].

OBJECTIVE: To discuss the attitudes in the assessment of environmental exposures as risk factors associated with neural tube defects, and to present the main risk factors studied to date. RESULTS: Environmental exposures have been suggested to have a roll in the genesis of birth defects. However, studies conducted in human populations have found difficulties in the design and conduction to show such an association for neural tube defects (anencephaly, espina bifida and encephalocele) because of problems raised from: a) the frequency measures used to compare time trends and communities, b) the classification of heterogeneous malformations, c) the inclusion of maternal, paternal and fetal factors as an integrated process and, d) the assessment of environmental exposures. CONCLUSIONS: Hypothetically both maternal and paternal environmental exposures can produce damage before and after conception by direct action on the embryo and the fetus-placenta complex. Therefore, in the assessment of environmental exposures we need to take into account: a) both paternal and maternal exposures; b) the critical exposure period, three months before conception for paternal exposures and one month around the conceptional period for maternal exposures; c) quantitatively evaluate environmental exposures when possible, avoiding a dichotomous classification; d) the use of biological markers of exposure is highly recommended as well as markers of genetic susceptibility.

Environmental Exposure↗
PubMed1980

Increased risk of recurrence of pregnancies complicated by fetal neural tube defects in mothers receiving poor diets, and possible benefit of dietary counselling.

One hundred and seventy-four women who had previously had a child with a neural-tube defect were assessed retrospectively on the quality of their diets during the first trimester of that pregnancy, between pregnancies, and during the first trimester of other pregnancies. They were then studied prospectively during the first trimester of 186 following pregnancies and the outcome of these was recorded. One hundred and three women (with 109 pregnancies) were given dietary counselling before the pregnancy, the remaining 71 (with 77 pregnancies) not being counselled. Seventy-eight (72%) of the counselled women improved their diet compared with only nine (12%) of the uncounselled women. The difference was significant (p < 0.001). There were three recurrences of neural-tube defects in the counselled women (3%) and five recurrences in the uncounselled (7%). Although this difference was not significant, the relative risk in the counselled group was reduced to less than half of that in the uncounselled group. All eight recurrences occurred in the 45 pregnancies in women taking poor diets (18%), whereas there were no recurrences in the 141 other pregnancies. This difference is significant (p < 0.001). It is concluded that women receiving adequate diets have a lower incidence and recurrence of fetal neural-tube defects than women receiving poor diets and that dietary counselling may be effective in reducing the incidence of fetal neural-tube defects.

Counseling↗
PubMed2003

[C677T and A1298C MTHFR polymorphisms in the etiology of neural tube defects in Spanish population].

BACKGROUND AND OBJECTIVE: The etiology of neural tube defects (NTDs) is multifactorial. The presence of mutated genotypes of C677T and A1298C polymorphisms, and their combined heterozygosity, have been considered risk factors for the occurrence and recurrence of NTDs in some populations. SUBJECTS AND METHOD: This case-control study included 159 healthy controls, 27 NTDs patients, 28 patients' mothers and 23 siblings. The polymorphism study was performed by PCR. For fragment digestion, we used the restriction enzymes Hinf I (C677T) and Mbo II (A1298C). RESULTS: There was no significant difference (p = 0.991) in C677T genotypes between controls (CC: 35%, CT: 50% and TT: 15%) and patients (37, 52 and 11%, respectively), patients' mothers (39, 50 and 11%, respectively) and siblings (35, 48 and 17%, respectively). The prevalence of A1298C genotypes in controls (AA: 49%, AC: 45% and CC: 6%) was similar (p = 0.917) to the prevalence in patients (41, 56 and 4%, respectively), patients' mothers (43, 50 and 7%, respectively) and siblings (52, 39 and 9%, respectively). CONCLUSIONS: The absence of differences in the two polymorphisms between these groups makes us conclude that there is no association with NTDs in the Spanish population.

Case-Control Studies↗
PubMed2003

[Clinical features of 3798 perinatals suffering from syndromic neural tube defects].

OBJECTIVE: To investigate the patterns and associated malformations in neural tube defects (NTDs) cases. METHODS: From 1987 to 1995, hospital-based cluster sampling method was adopted for collecting data. During that period all live or still births with 28 weeks of gestation or more were assessed within 7 days after delivery. RESULTS: Three thousand seven hundred and ninety eight syndromic NTDs were identified, among which anencephaly, spina bifida and encephalocele were 997, 2394 and 407 respectively. 51.3% associated abnormalities of NTDs appeared in muscle and skeletal system, 19.6% in face, ear and neck, and 9.3% in urinary-genital system. Congenital talipes equinovarus, cleft lip with cleft palate, gastroschisis, talipes valgus, undescended testicle were frequently combined with NTDs. The most frequent association in schisis type of NTDs was NTDs accompanied by cleft lip with or without cleft palate (67.5%), followed by anencephaly with cleft palate (8.3%) and anencephaly with omphalocele (6.6%). Of all syndromic NTDs, the rate of low birth weight was 36.9%, of perinatal mortality was 71.2% and the ratio 33.1% patients were diagnosed prenatally. CONCLUSIONS: Approximately one third of NTDs may be associated with other system's malformation. Syndromic NTDs has a high perinatal mortality rate and a poor prognosis.

Abnormalities, Multiple↗
PubMed2004

Periconceptional dietary intake of choline and betaine and neural tube defects in offspring.

Periconceptional intake of folic acid prevents some neural tube defects (NTDs). Other nutrients may also contribute to NTD etiologies; a likely candidate is choline. Similar to folic acid, choline is involved in one-carbon metabolism for methylation of homocysteine to methionine. The authors investigated whether maternal periconceptional dietary intakes of choline and its metabolite betaine influence NTD risk. Data were derived from a case-control study of fetuses and infants with NTDs among 1989-1991 California births. In-person interviews were conducted with mothers of 424 NTD cases and with mothers of 440 nonmalformed controls. A standard 100-item food frequency questionnaire was used to assess nutrient intake. Dietary intakes of choline were associated with reduced NTD risks. Controlling for intake of supplemental folic acid, dietary folate, dietary methionine, and other covariates did not substantially influence risk estimates for choline. NTD risk estimates were lowest for women whose diets were rich in choline, betaine, and methionine. That is, for women whose intake was above the 75th percentile compared with below the 25th percentile for all three nutrients, the odds ratio was 0.17 (95% confidence interval: 0.04, 0.76). Study findings for dietary components other than folic acid offer additional clues about the complex etiologies of NTDs.

Betaine↗
PubMedDate not supplied

Awareness of folic acid for prevention of neural tube defects in a community with high prevalence of consanguineous marriages.

Neural tube defects (NTDs) are severe congenital malformations and can be fatal. Intake of 0.4 mg folic in the periconceptional period reduces the risk of NTD by 50-70%. Consanguinity in the Arab population in Israel is a prevalent custom. The aim of this study was to assess the level of awareness regarding folic acid and its effect in the prevention of NTD among Arab Israeli women of childbearing age. We conducted a cross-sectional study. Of the 653 women (18-45 years) who were randomly selected for interview while visiting their family physician or well-baby clinic, 624 women completed the questionnaire. Fifty-three percent (n = 333) of the respondents had heard of folic acid; 14% (n = 89) were familiar with the protective effect of NTD and 3% (n = 18) had taken folic acid in the first months of pregnancy whereas none of them had used it in the preconception period. Highly educated women, women with one or two children, paramedics, and women of high socioeconomic status were more knowledgeable about the protective effects of folic acid (P < 0.001). Age and religion had no significant effect. An urgent need exists to improve the awareness of this population to the protective effect of folic acid. Daily supplementation and fertification of food with folic acid should be considered as the best way to improve the balance of folic acid in women of childbearing age of this special population (high prevalence of consanguinity).

Adolescent↗
PubMed1996

Multigeneration maternal transmission in Italian families with neural tube defects.

Periconceptional vitamin supplementation with folate prevents about three-quarters of expected cases of neural tube defects (NTDs) in clinical trials. However, vitamin action may be regulated at the level of the gene, and individual susceptibility to environmental agents, including dietary components, also may be under genetic control. We investigated the presence of familial factors in a retrospective case control study of neural tube defects in Genoa, Italy. Cases included all patients treated at a single pediatric neurosurgical service. Controls matched on age and sex came from the same hospital. We found strong evidence for the contribution of genetic factors in this study. There was an excess risk of 14 for the occurrence of NTDs in first-degree relatives compared to controls (P < .0005). There was no difference in sex ratio in any group of relatives, but maternal grandparents of children with a high spinal lesion had 14% fewer off-spring than paternal grandparents (P < .005), possibly because of excess miscarriages. Our study is the first to show complex patterns of inheritance in spina bifida families affecting three generation in one clinical subgroup and preferentially on the mother's side. These results support a role for genomic imprinting and highlight the value of multidisciplinary epidemiologic and clinical studies that include multiple generations. New studies incorporating dietary and genetic approaches will help clarify and extend these findings.

Adolescent↗
PubMed2003

Homocysteine remethylation enzyme polymorphisms and increased risks for neural tube defects.

Folic acid supplementation can effectively reduce the risk of neural tube defects (NTDs); however, the mechanism underlying this beneficial effect remains unclear. Recent evidence suggests that certain folate pathway genes, as well as those related to homocysteine metabolism might be contributing to this effect. The purpose of this study is to investigate whether gene polymorphisms of methionine synthase (MTR) and methionine synthase reductase (MTRR) are involved in the risk for NTDs, specifically spina bifida. We detected MTR A2756G and MTRR A66G polymorphisms using PCR-RFLP analysis in a group of NTD infants, their mothers and normal controls. We found that infants with the MTRR mutant genotype had a 2.6-fold higher risk of NTDs when compared to the AA genotype (OR = 2.6, 95%CI = 1.3-5.3). Mothers with the MTRR mutant genotype also had a 1.9-fold higher risk of having an NTD baby compared to AA genotype (OR = 1.9, 95%CI = 1.1-3.1). Infants who carry mutant alleles for both MTRR and MTR had exceptionally elevated NTD risks, with odds ratios of 5.1 compared to infants with the wild type genotype at both loci (AA + AA) (OR = 5.1, 95%CI = 1.7-15.4). A comparable result was observed in the mothers of NTD cases (OR = 2.1, 95%CI = 1.0-4.7). Our results indicate that MTRR and MTR genes may interact to increase the infants' NTD risks. These results did not appear to be influenced by maternal periconceptional folic acid intake. However,the sample size of this study was limited, and a larger population study is needed to pursue these initial observations.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed1982

Neural tube defects among twin births.

To obtain accurate, unbiased rates of neural tube defects (NTDs) in twins, we conducted a population-based study that included live births and fetal deaths in Los Angeles County, California, ascertaining cases by multiple methods. Twenty-eight twin cases yielded a prevalence-at-birth of 1.6/1,000 twin births, which is significantly higher than the singleton prevalence of 1.1/1,000 births. In twins compared with singletons, the prevalences of both encephalocele and anencephaly are increased, whereas spina bifida is decreased. The twin case male/female sex ratio (.55) is lower than the singleton case sex ratio (.77). Concordance is relatively low at 3.7%, but appears to be higher than recently reported recurrence risks in other low prevalence areas. Stillbirths were most common among female cases and like-sex twins. Our study tends to support proposed etiologic theories associating NTDs with females or monozygotic twins, or both. There is increasing evidence that the etiology of NTDs may differ in high and low prevalence areas. We suggest also that twins and singletons may differ in their response to etiologic factors. The variations among anencephaly, spina bifida, and encephalocele in their association with twinning suggest that there may be different factors that influence the development of each specific NTD. The noted differences among the malformations also indicate that some of the variation among results of other studies of NTDs and twinning may be due to case ascertainment. Including spina bifida cases would decrease the proportion of twins in a study population, while including anencephalics would increase the proportion. Importantly, ascertaining fetal deaths would increase the proportion of anencephalics and case females, so studies of NTDs that do not include fetal deaths will show fewer twins than expected. On the basis of our findings and those of Layde et al., excluding encephaloceles will also decrease the number of twins among NTD cases. When investigating etiologic hypotheses for NTDs, these potential biases must be recognized.

Adult↗
PubMed1998

Raised levels of maternal serum secretory acetylcholinesterase may be indicative of fetal neural tube defects in early pregnancy.

BACKGROUND: To investigate the levels of maternal serum secretory acetylcholinesterase from a sample of pregnancies involving fetal neural tube defects and compare those results with alphafetoprotein levels. METHODS: Secretory acetylcholinesterase levels were measured using a new Enzyme Capture Immunoassay, in a small blind prospective study. The study group comprised pregnancies covering a gestational age range of 13-24 weeks where 98 had normal fetuses, 21 suffered from neural tube defects, and 15 had other complications. RESULTS: Maternal serum secretory acetylcholinesterase levels were found to be low and independent of gestational age between 14-20 weeks in a sample of normal pregnancies with normal alphafetoprotein levels. Raised levels of maternal serum secretory acetylcholinesterase were found in 100% of pregnancies involving spina bifida (17/17) and three of four anencephalics compared with raised alphafetoprotein levels found in 88% (15/17), and 100% (4/4) of the same samples. Only seven of 13 maternal serum samples from pregnancies with a normal outcome and none of the four twin pregnancies, all with raised alphafetoprotein levels, had raised secretory acetylcholinesterase levels. CONCLUSIONS: Raised levels of maternal serum secretory acetylcholinesterase may provide a useful indicator of neural tube defects in early pregnancy.

Acetylcholinesterase↗
PubMed1982

Amniotic fluid acetylcholinesterase electrophoresis in the prenatal diagnosis of neural tube defects.

Amniotic fluid acetylcholinesterase electrophoresis has become available as a test for the prenatal diagnosis of open neural tube defects. The results of acetylcholinesterase electrophoresis on 125 amniotic fluid samples, including 18 from fetuses with open neural tube defects, are presented. These results indicate that this test, in conjunction with alpha-fetoprotein measurement, is of considerable practical value.

Acetylcholinesterase↗
PubMed1998

[Prevention of neural tube defects. An important health and social problem].

Central neural system congenital malformations in the form of neural tube defects (ntd) belong to the most common diseases leading to very serious childrens' disability and mortality. As it has been calculated, the number of children affected with ntd, delivered in Poland every year is in the range of 800-1150. Children with encephalocele participate in this number in app. 50%. As it has been found, morbidity and mortality caused by the ntd remain high and stable in Poland for the last 20 years. In the view of very limited possibilities of the treatment offered by health services, prophylactic measures remain the best methods for limitation of the problem. The primary prevention of ntd was discovered in late seventies. It has been found that folic acid added to the diet of women in the reproductive age reduced number of children born with ntd by 70%. Authors present the Programme of Primary Prevention of ntd in Poland. This Programme has been incorporated in the National Programme of Health for the Nation 1996-2005.

Adult↗