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PubMed1987

Incidence and distribution of renal anomalies in patients with neural tube defects.

In 190 patients with neural tube defects the sensory levels to pin prick were compared with the incidence and distribution of congenital renal anomalies. 17 such anomalies comprised 3 examples of renal agenesis, 5 horseshoe kidneys, 8 ureteral duplications and one simple ureterocele. The pattern of anomalies showed that renal agenesis was associated with a sensory level in the dermatomes T5-8, horseshoe kidneys with T9-L1 and duplications predominantly with the sacral dermatomes.

Abnormalities, Multiple↗
PubMedDate not supplied

[Neural tube defects and associated factors in liveborn and stillborn infants].

OBJECTIVES: To evaluate the prevalence and factors associated to neural tube defects in liveborn and stillborn infants delivered at the Hospital das Clínicas, UFMG, from January 8, 1999 to July 31, 2000. METHODS: This is a descriptive study, based on a database, according to the Latin-American Collaborative Study of Congenital Malformation (ECLAMC) rules. Reports on liveborn and stillborn infants with congenital anomalies were prepared including information about morphological description, necropsy results, complementary exams, family, social and pregnancy histories and other clinical data. Each malformed liveborn infant originated a control of the same sex, without malformations. The liveborn and stillborn infants with neural tube defects delivered during that period were classified according to their defect and the presence or absence of associated defects. The liveborn and stillborn infants with neural tube defects were compared to newborns without neural tube defects according to their weight and sex and their mother's age and parity. Epi-Info 6.0 Program was used for the statistical analysis of the results. RESULTS: The prevalence of neural tube defects was 4.73 to 1,000 deliveries (89:18,807); it was significantly higher among stillborn infants (23.7:1,000) than among liveborn infants (4.16:1,000), p < 0.001. Neural tube defects were more often found among low weight liveborn infants (< or = 2,500 g), p < 0.001 and less frequently among women who had had more than three gestations, p = 0.007. No association was found regarding newborn's sex or maternal age. There was no association with newborn's sex and weight, maternal parity or age among stillborn infants. The most common neural tube defects were myelomeningocele (47.2%), anencephaly (26.9%) and encephalocele (16.9%). The defects were found as isolated anomalies in 71.1% of the liveborn and 38.5% of the stillborn infants; they were part of a syndrome in 9.2% (liveborn) and 7.7% (stillborn). CONCLUSION: The neural tube defect prevalence found in this study was higher than the one described in international and Latin-American literature.

Female↗
PubMed2006

Assessment of the potential effect of incremental increases in folic acid intake on neural tube defects in Australia and New Zealand.

OBJECTIVE: To estimate the number of neural tube defects that could be prevented in Australia and New Zealand by increasing levels of folic acid intake. METHODS: Available data on prevalence of neural tube defects in Australia and New Zealand, folic acid supplement use and serum folate were used in a published model to estimate the number of neural tube defects that could be prevented in Australia and New Zealand for increments of folic acid intake from 0.1 mg daily to 1 mg daily. RESULTS: An increase of 0.2 mg folic acid per day was estimated to result in the prevention of 49 (95% CI 27-84) neural tube defects per year in Australia and 11 (95% CI 6-18) in New Zealand. A separate estimation for Indigenous Australians found that 0.2 mg of folic acid daily could prevent 7 (95% CI 4-11) neural tube defects in Indigenous infants per year. CONCLUSIONS: These data should be useful in considering primary preventive strategies for neural tube defects, including the possible introduction of mandatory fortification of food with folic acid. The estimates are imprecise because of limitations in the data used in the model. IMPLICATIONS: More representative and precise data on neural tube defects, serum folate levels and use of folic acid supplements from all Australian States and New Zealand are needed to refine the output from the model and to provide a baseline assessment of folate status against which to measure the effects of any future interventions to prevent neural tube defects.

Australia↗
PubMed1989

Changing incidence of neural tube defects in Aegean Turkey.

The incidence of neural tube defects was monitored among all live- and still-births delivered between June 1986 and July 1988. In all there were 19,115 total births. The incidence of neural tube defects (NTD) was 1.9 per 1000 among those whose conception time was prior to May 1986. However, in conceptions occurring in May, June and July 1986, the NTD rate increased to a level of 8.9 per 1000, subsequently gradually declining to previous levels within 9 months. This dramatic change in incidence, which parallels a previous finding from Turkey, suggests that this finding may be associated with the Chernobyl disaster of May 1986.

Accidents↗
PubMed1985

Analysis of the changing birth prevalence of neural tube defects in Hungary.

The birth prevalence of neural tube defects had a significant decrease in Hungary from the sixties till 1978. After this a slight but not significant increase was registered. The changing pattern had no correlation with the developmental (different groups of neural tube defects, still- and livebirth rate, sex ratio, birth weight distribution and twin rate), demographic (monthly and territorial distribution, maternal age, birth order) and medical (prevention program, genetic counselling) factors. There was only one obvious finding, a negative correlation with the standard of living of the population.

Anencephaly↗
PubMed1991

Importance of accurate diagnosis in counseling for neural tube defects diagnosed prenatally.

In cases of fetal neural tube defects (NTD), termination of pregnancy without ascertainment of specific etiology may lead to provision of incorrect recurrence risks and erroneous diagnosis in future pregnancies. Four patients are presented who illustrate the etiologic diversity of neural tube defects. The patients were referred for prenatal diagnosis because of elevated maternal serum alphafetoprotein (AFP). All four chose pregnancy termination. Diagnostic methods included fetal ultrasound, amniocentesis for fetal karyotyping and amniotic fluid AFP/acetylcholinesterase (AChE) and/or fetal karyotyping after delivery, and dysmorphology evaluation of the fetus after intact delivery. These cases highlight the benefits of fetal karyotype analysis and of an intact delivery and thorough clinical examination of the fetus when patients choose to terminate pregnancies with fetal anomalies.

Abnormalities, Multiple↗
PubMed2004

Awareness of the use of folic acid to prevent neural tube defects in a Mediterranean area.

OBJECTIVES: The risk of neural tube defects (NTDs) is decreased in women who take folic acid during the periconceptional period. The main objective of our study was to evaluate the awareness of the need for folic acid supplementation and also the actual intake during the periconceptional period to prevent neural tube defects in a Mediterranean area. STUDY DESIGN: A retrospective study was performed from 1 July to 30 November 2000. One thousand consecutive women who delivered in our hospital were interviewed during the immediate postpartum period about their knowledge of neural tube defects and folic acid intake before and during pregnancy. RESULTS: Most women (85.7%) referred not having been specifically informed about the need to take folic acid to prevent neural tube defects although approximately half of the women (50.6%) were in fact, aware of the need for folic acid intake. Eight percent (8.1%) of the women took folic acid before conception but only 6.9% did so during the effective period from 4 weeks before conception to 4 weeks after conception. Logistic regression analysis showed that awareness of the need to take folic acid together with having had preconceptional counselling and knowledge of NTDs were the strongest variables related to the fact of having taken folic acid during the correct period. CONCLUSIONS: Although the population is aware of the need to take folic acid, the real impact of the present recommendations is almost negligible. Information in primary care and preconceptional counselling to specifically inform patients about the need to take folic acid to prevent NTDs seem to be crucial to improve the final intake of folic acid during the protective period.

Adult↗
PubMed2002

[Upper and lower neural tube defects: prevalence and association with illnesses and drugs].

OBJECTIVE: To determine the prevalence of upper and lower neural tube defects and identify its association with the exposure to illnesses and drugs during pregnancy. MATERIAL AND METHODS: This is a case-control study of 107 newborns with upper neural tube defects, 59 with lower neural tube defects, and 166 newborns without malformations, in 56,926 consecutive births between 1989 and 1997. The exposure was documented by a direct interview to the mother of those subject of study. The association was measured by the odds ratios, with confidence interval of 95%. RESULTS: The prevalence of upper neural tube defects was of 1.9 for 1,000 newborn (alive or dead) and of lower neural tube defects of 1.0 for 1,000. The exposure to illnesses of less than a month of duration was associated with upper neural tube defects (OR = 3.11; IC = 1.34-7.39) the most important was flu; also the exposure to drugs (OR = 5.85; IC = 2.97-11.62), the most prominent was acetaminophen. These factors of risk were not associated with lower neural tube defects. The mother's occupation, illness of more than a month of duration and X-ray exposure were not associated with of upper and lower neural tube defects. CONCLUSIONS: More studies are needed in the association among illnesses of less than a month of duration and drugs with upper neural tube defects. The different exposure frequencies between upper and lower neural tube defects suggest heterogeneity.

Acetaminophen↗
PubMed1978

Neural tube defects: maternal serum screening and prenatal diagnosis.

Neural tube defects represent some of the most common and serious of the congenital malformations. Although elevation of alpha-fetoprotein in amniotic fluid is not diagnostic, it does indicate an abnormality of the fetus in a very high proportion of cases. A normal level, however, does not exclude the possibility of a closed neural tube defect. It is therefore recommended that all amniocenteses performed between 15 and 20 weeks of gestation include measurement of alpha-fetoprotein. Maternal serum alpha-fetoprotein assay is a screening test and pilot studies will be necessary to determine its value as a routine prenatal blood test.

Amniocentesis↗
PubMed2003

Transcobalamin and methionine synthase reductase mutated polymorphisms aggravate the risk of neural tube defects in humans.

The pathogenic mechanism of neural tube defects may involve genetic polymorphisms and nutritional factors related to homocysteine metabolism. We evaluated the association of polymorphisms of three genes affecting vitamin B12-dependent remethylation of homocysteine, transcobalamin (TC), methionine synthase (MTR) and MTR reductase (MTRR), combined or not with methylenetetrahydrofolate reductase (MTHFR), with the risk of having neural tube defect in 40 children with spina bifida and 58 matched controls from South Italy. MTR 2756 AG/GG, TC 777 CG/GG /MTHFR 677 CC and MTRR 66 GG /MTHFR 677 CC genotypes increased the risk with odds ratios of 2.6 (P=0.046), 2.4 (P=0.028) and 4.5 (P=0.023), respectively. In contrast, MTHFR 677 TT was protective (odds ratio=0.11, P=0.009). In conclusion, genetic determinants affecting the cellular availability or MTRR-dependent reduction of B12 may increase the risk of spina bifida.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed1986

Neural tube defects in spontaneous abortions.

Nine specimens with neural tube defects (NTDs) were ascertained in a consecutive series of spontaneous abortions in New York City, giving a rate of 10.2 per 1,000 testable embryos and fetuses. All seven successfully karyotyped abortions had a chromosome anomaly. The rate of NTDs in miscarriages in New York is only one-third the rate in miscarriages in London, and the difference is due entirely to a deficit of fetuses with normal chromosomes. Our data, together with data from three other centers, indicate that there is a strongly positive association (r = 0.96) between rates of neural tube defects in early pregnancy and at term. The implications of these findings for genetic counseling and for etiologic studies are discussed.

Abortion, Spontaneous↗
PubMed1995

Parent preferences and prenatal testing for neural tube defects.

Previous analyses of prenatal screening for neural tube defects have generally found benefits to exceed costs. The usual screening battery follows an elevated maternal serum alpha-fetoprotein level with high-resolution ultrasound and/or amniocentesis. Current thinking focuses on weighing the risk of a false-negative (an abnormality missed) against the risk of an amniocentesis-induced fetal loss. This thinking neglects the risk of a false-positive (an unaffected fetus labeled abnormal) and individual parents' preferences concerning a false-negative vs a fetal loss. With these risks included, we find that high-resolution ultrasound is appropriate for all women with elevated serum alpha-fetoprotein. Women with moderately elevated serum alpha-fetoprotein who have negative ultrasound scans need no further testing, nor do women with highly elevated serum alpha-fetoprotein and positive ultrasound scans. Further testing using amniocentesis to confirm the ultrasound result is appropriate for women with moderately elevated serum alpha-fetoprotein and positive ultrasound scans, and for women with highly elevated serum alpha-fetoprotein and negative ultrasound scans. The actual cutoffs defining normal, moderately elevated, and highly elevated serum alpha-fetoprotein depend on several parameters, particularly the underlying prevalence of neural tube defects and the parents' preferences.

Cost-Benefit Analysis↗
PubMedDate not supplied

Folic acid for prevention of neural tube defects: pediatric anticipatory guidance.

The incidence of neural tube defects including myelomeningocele, which is one of the most common causes of infant and childhood disability, can be substantially reduced by folic acid supplementation to the diet of women before and during the early stages of pregnancy. All females of childbearing age should be taking folic acid supplements of 0.4 mg/day (400 micrograms/day) and consuming a diet rich in folate. Because many pregnancies are unplanned, supplementation should not await plans for pregnancy. Because pediatric nurse practitioners are in frequent contact with both adolescent patients and patients whose mothers are of childbearing age, and because pediatric nurse practitioners have an interest in preventing neural tube defects in future pediatric patients, they are in a good position to provide the necessary anticipatory guidance regarding the critical need for adequate folic acid intake by females of childbearing age. This article discusses and includes guidelines for providing this anticipatory guidance.

Adult↗
PubMed1984

Recurrence risk after neural tube defects in a genetic counselling clinic.

The recurrence of isolated neural tube defects in a population of women from a genetic counselling clinic was found to be 3.4%. After one baby with a neural tube defect the recurrence was 2.3%. Of the 15 pregnancies of women who had two previous babies with neural tube defects, there were three further recurrences. These findings show that the Hungarian recurrence risk of isolated neural tube defects has not changed with a declining birth prevalence, and that the rate in genetic counselling clinic patients is the same as in a previous population based epidemiological study.

Abnormalities, Multiple↗
PubMed2002

Genetic basis of neural tube defects. I. Regulatory genes for the neurulation process.

Neural tube defects (NTD) together with cardiovascular system defects are the most common malformations in the Polish population (2.05-2.68/1000 newborns). They arise during early embryogenesis and are caused by an improper neural groove closure during the neurulation process. NTD can arise from the influence of specific environmental factors on the foetus. The genetic factor is also very important, because NTDs have multigenetic conditioning. It was suggested that genes connected with the regulation of neurulation could also be involved in NTD aetiology, especially when their deletion or modification leads to neural tube defects in the mouse model. Examples are genes from the PAX family, T (Brachyury), BRCA1 and PDGFRA genes.

Animals↗
PubMed1994

Genetic models of mammalian neural tube defects.

Several mouse mutations disturb the embryonic process of neurulation, yielding neural tube defects. Analysis of the mutations offers the most feasible approach to understanding the aetiology and pathogenesis of human neural tube defects. Interactions between the non-allelic mutant genes and between several of the mutant genes and modifying genes in the genetic background modulate the frequency and severity of the defects that develop. Environmental factors interact with the genetic predisposition either to increase or to decrease the incidence of defects. The gene loci corresponding to two of the mutations, splotch (Sp) and extra toes (Xt), have been identified as those encoding the transcription factors Pax-3 and Gli3, respectively; their human homologues are associated with Waardenburg type I syndrome and Greig's cephalopolysyndactyly. Embryological analysis reveals that several of the mutations disturb the process of neural tube closure at the posterior neuropore (in the lumbosacral region), yielding spina bifida and/or tail defects. The different mutations appear to achieve this developmental end-point by different underlying mechanisms. In curly tail (ct), non-neural tissues proliferate abnormally slowly causing ventral curvature of the neuropore region and inhibiting neural tube closure. Neural tube defects can be prevented in cultured ct/ct embryos by experimentally correcting either the proliferative imbalance or the ventral curvature. In Sp the primary defect appears to reside in the neuroepithelium. A combination of genetic analysis, gene cloning and experimental embryology is revealing that neural tube defects in mice and, by implication, in humans are a developmentally heterogeneous group of malformations.

Animals↗
PubMed1995

Neural tube defects, chromosome abnormalities and multiple closure sites for the human neural tube.

The hypothesis that during human embryogenesis there is multi-site closure of the neural tube, with possibly regionally distinct genetic control, is examined in the light of the neural tube defects (NTD) observed in trisomy 13, trisomy 18 and triploidy which survive at least to the mid-trimester. In a series of mid-trimester fetuses examined post-mortem, there were two spina bifidas in 25 cases of trisomy 13; eight spina bifidas and one anencephalic among 38 trisomy 18 individuals; and three spina bifidas in 13 triploids. Not only was there a predominance of spina bifida, but all the spina bifidas were similar in location along the neuraxis: regardless of chromosome constitution, they were all sacral or lumbosacral. A survey of the literature confirms this finding. While this regionally distinct type of NTD is not specific to a particular chromosome abnormality and thus by implication to any particular gene, it does seem to be specific to an imbalance caused by an excess of genetic material of a type which permits survival past the first few post-conception weeks, and thus lends some support to the hypothesis.

Chromosome Aberrations↗
PubMed1992

Prevention of the first occurrence of neural-tube defects by periconceptional vitamin supplementation.

BACKGROUND: The risk of recurrent neural-tube defects is decreased in women who take folic acid or multivitamins containing such during the periconceptional period. The extent to which folic acid supplementation can reduce the first occurrence of defects is not known. METHODS: We conducted a randomized, controlled trial of periconceptional multivitamin supplementation to test the efficacy of this treatment in reducing the incidence of a first occurrence of neural-tube defects. Women planning a pregnancy (in most cases their first) were randomly assigned to receive a single tablet of a vitamin supplement (containing 12 vitamins, including 0.8 mg of folic acid; 4 minerals; and 3 trace elements) or a trace-element supplement (containing copper, manganese, zinc, and a very low dose of vitamin C) daily for at least one month before conception and until the date of the second missed menstrual period or later. RESULTS: Pregnancy was confirmed in 4753 women. The outcome of the pregnancy (whether the fetus or infant had a neural-tube defect or congenital malformation) was known in 2104 women who received the vitamin supplement and in 2052 who received the trace-element supplement. Congenital malformations were significantly more prevalent in the group receiving the trace-element supplement than in the vitamin-supplement group (22.9 per 1000 vs. 13.3 per 1000, P = 0.02). There were six cases of neural-tube defects in the group receiving the trace-element supplement, as compared with none in the vitamin-supplement group (P = 0.029). The prevalence of cleft lip with or without cleft palate was not reduced by periconceptional vitamin supplementation. CONCLUSIONS: Periconceptional vitamin use decreases the incidence of a first occurrence of neural-tube defects.

Cleft Lip↗