A Genome-wide Association Study of Nonsyndromic Cleft Palate Identifies an Etiologic Missense Variant in GRHL3.

Cleft palate (CP) is a common birth defect occurring in 1 in 2,500 live births. Approximately half of infants with CP have a syndromic form, exhibiting other physical and cognitive disabilities. The other half have nonsyndromic CP, and to date, few genes associated with risk for nonsyndromic CP have been characterized. To identify such risk factors, we performed a genome-wide association study of this disorder. We discovered a genome-wide significant association with a missense variant in GRHL3 (p.Thr454Met [c.1361C>T]; rs41268753; p = 4.08 × 10(-9)) and replicated the result in an independent sample of case and control subjects. In both the discovery and replication samples, rs41268753 conferred increased risk for CP (OR = 8.3, 95% CI 4.1-16.8; OR = 2.16, 95% CI 1.43-3.27, respectively). In luciferase transactivation assays, p.Thr454Met had about one-third of the activity of wild-type GRHL3, and in zebrafish embryos, perturbed periderm development. We conclude that this mutation is an etiologic variant for nonsyndromic CP and is one of few functional variants identified to date for nonsyndromic orofacial clefting. This finding advances our understanding of the genetic basis of craniofacial development and might ultimately lead to improvements in recurrence risk prediction, treatment, and prognosis.

A multi-ethnic genome-wide association study identifies novel loci for non-syndromic cleft lip with or without cleft palate on 2p24.2, 17q23 and 19q13.

Orofacial clefts (OFCs), which include non-syndromic cleft lip with or without cleft palate (CL/P), are among the most common birth defects in humans, affecting approximately 1 in 700 newborns. CL/P is phenotypically heterogeneous and has a complex etiology caused by genetic and environmental factors. Previous genome-wide association studies (GWASs) have identified at least 15 risk loci for CL/P. As these loci do not account for all of the genetic variance of CL/P, we hypothesized the existence of additional risk loci. We conducted a multiethnic GWAS in 6480 participants (823 unrelated cases, 1700 unrelated controls and 1319 case-parent trios) with European, Asian, African and Central and South American ancestry. Our GWAS revealed novel associations on 2p24 near FAM49A, a gene of unknown function (P = 4.22 × 10-8), and 19q13 near RHPN2, a gene involved in organizing the actin cytoskeleton (P = 4.17 × 10-8). Other regions reaching genome-wide significance were 1p36 (PAX7), 1p22 (ARHGAP29), 1q32 (IRF6), 8q24 and 17p13 (NTN1), all reported in previous GWASs. Stratification by ancestry group revealed a novel association with a region on 17q23 (P = 2.92 × 10-8) among individuals with European ancestry. This region included several promising candidates including TANC2, an oncogene required for development, and DCAF7, a scaffolding protein required for craniofacial development. In the Central and South American ancestry group, significant associations with loci previously identified in Asian or European ancestry groups reflected their admixed ancestry. In summary, we have identified novel CL/P risk loci and suggest new genes involved in craniofacial development, confirming the highly heterogeneous etiology of OFCs.

Identification of functional variants for cleft lip with or without cleft palate in or near PAX7, FGFR2, and NOG by targeted sequencing of GWAS loci.

Although genome-wide association studies (GWASs) for nonsyndromic orofacial clefts have identified multiple strongly associated regions, the causal variants are unknown. To address this, we selected 13 regions from GWASs and other studies, performed targeted sequencing in 1,409 Asian and European trios, and carried out a series of statistical and functional analyses. Within a cluster of strongly associated common variants near NOG, we found that one, rs227727, disrupts enhancer activity. We furthermore identified significant clusters of non-coding rare variants near NTN1 and NOG and found several rare coding variants likely to affect protein function, including four nonsense variants in ARHGAP29. We confirmed 48 de novo mutations and, based on best biological evidence available, chose two of these for functional assays. One mutation in PAX7 disrupted the DNA binding of the encoded transcription factor in an in vitro assay. The second, a non-coding mutation, disrupted the activity of a neural crest enhancer downstream of FGFR2 both in vitro and in vivo. This targeted sequencing study provides strong functional evidence implicating several specific variants as primary contributory risk alleles for nonsyndromic clefting in humans.

Ear Infection in Isolated Cleft Lip: Etiological Implications.

BACKGROUND AND HYPOTHESIS: Chronic ear infections are a common occurrence in children with orofacial clefts involving the secondary palate. Less is known about the middle ear status of individuals with isolated clefts of the lip, although several studies have reported elevated rates of ear infection in this group. The purpose of this retrospective study was to test the hypothesis that chronic ear infections occur more frequently in isolated cleft lip cases (n = 94) compared with controls (n = 183). METHODS: A questionnaire was used to obtain information on history of chronic ear infection. The association between ear infection status (present/absent) and cleft lip status (cleft lip case/control) was tested using both chi-square and logistic regression. RESULTS AND CONCLUSIONS: The reported occurrence of chronic ear infection was significantly greater in cleft lip cases (31%) compared with unaffected controls (11%). After adjusting for age and sex, having a cleft lip increased the odds of being positive for ear infection by a factor greater than 3 (odds ratio = 3.698; 95% confidence interval = 1.91 to 7.14). Within cleft lip cases, there was no difference in the occurrence of ear infection by defect laterality or by the type of clefting present in the family history. Although velopharyngeal insufficiency was present in 18.4% of our cleft lip sample, there was no statistical association between ear infection and abnormal speech patterns. These results may have potential implications both for the clinical management of isolated cleft lip cases and for understanding the etiology of orofacial clefting.

Paroxysmal supraventricular tachycardia in pregnant women and birth outcomes of their children: a population-based study.

The aim of the study was to estimate the possible association of pregnant women with paroxysmal supraventricular tachycardia (PSVT) with the possible risk for adverse birth outcomes, particularly different congenital abnormalities (CAs) in their children. Prospectively and medically recorded PSVT was evaluated in 103 pregnant women who later had offspring with CA (case group) and 149 pregnant women who later delivered newborn infants without CA (control group) and matched to cases in the population-based data set of the Hungarian Case-Control Surveillance System of Congenital Abnormalities, 1980-1996. Of 252 pregnant women with PSVT, 115 (45.6%) had the onset of this condition before the study pregnancy, that is, their PSVT was a chronic condition, while the rest (N = 137) of PSVT was considered as new onset in the study pregnancy. The comparison of occurrence of PSVT in pregnant women who had offspring with different CA groups and in control mothers showed a higher risk for cardiovascular CAs (adjusted OR with 95% CI: 2.1, 1.1-3.8) explained mainly by secundum atrial septal defect. This association was confirmed in pregnant women with PSVT in the second and/or third gestational month, that is, critical period of cardiovascular CAs. In conclusion PSVT in pregnant women associates with a higher risk of secundum atrial septal defect in their children.

Distribution of maternal age and birth order groups in cases with unclassified multiple congenital abnormalities according to the number of component abnormalities: a national population-based case-control study.

BACKGROUND: Multiple congenital abnormalities are caused by chromosomal aberrations, mutant major genes and teratogens. A minor proportion of these patients are identified as syndromes but the major part belonging to the group of unclassified multiple CAs (UMCAs). The main objective of this study was to evaluate the maternal age and birth order in pregnant women who had offspring affected with UMCA. The strong association between numerical chromosomal aberrations, e.g., Down syndrome and advanced maternal age is well-known and tested here. METHODS: The Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980 to 1996, yielded a large population-based national data set with 22,843 malformed newborns or fetuses ("informative cases") included 1349 UMCA cases with their 2407 matched controls. Case-control comparison of maternal age and birth order was made for cases with UMCA, stratified by component numbers and their controls. In addition, 834 cases with Down syndrome were compared to 1432 matched controls. RESULTS: The well-known advanced maternal age with the higher risk for Down syndrome was confirmed. The findings of the study suggest that the young age of mothers associates with the higher risk of UMCA, in addition birth order 4 or more associates with the higher risk for UMCA with 2 and 3 component CAs. CONCLUSION: This study was the first to analyze the possible maternal and birth order effect for cases with UMCA, and the young age and higher birth order associated with a higher risk for UMCA.

Maternal factors in the origin of isolated oesophageal atresia: A population-based case-control study.

BACKGROUND: In most patients affected by isolated oesophageal atresia (IOA) the etiology is largely unknown. Thus, the aim of this study was to analyze potential risk factors in mothers. METHODS: The study samples included 221 cases with IOA, 356 matched and 38,151 population controls without any defect in the population-based dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980 to 1996. Only those exposures were evaluated that were medically recorded in prenatal maternity logbooks during the critical period of IOA. RESULTS: The findings of this case-control study suggested that the mothers of cases with IOA had a higher proportion of first delivery and lower socioeconomic status. Acute respiratory diseases (odds ratio [OR] 95% confidence interval [CI], 3.8, 1.8-8.1) and essential hypertension treated with nifedipine (OR 95% CI, 3.8, 1.7-8.7) in the mothers of cases associated with a higher risk for IOA in their children. CONCLUSION: First delivery, lower socioeconomic status, acute respiratory diseases and essential hypertension treated with nifedipine in the mothers may associate with a higher risk for IOA in their children.

Birth Outcomes of Children Born to Women with Rheumatoid Arthritis.

AIM: The aim of the study was to estimate the possible risk of adverse birth outcomes of children born to mothers with rheumatoid arthritis (RA). METHODS: The dataset of large population-based Hungarian Case-Control Surveillance System of Congenital Abnormalities from 1980-1996 was evaluated including 22,843 cases with congenital abnormalities and 38,151 matched controls without any defect. RESULTS: 36 cases (0.16%) had mothers with RA, while 68 controls (0.18%) were born to mothers without RA (OR=0.9, 95% CI=0.3-1.6). A higher risk for congenital abnormalities in the offspring of pregnant women with RA was not found. In fact there was a larger mean birth weight in the newborns without any defect of mothers with RA and it was associated with a somewhat lower rate of low birth weight. CONCLUSIONS: RA seems to have a beneficial effect not only for pregnant women but for their foetuses as well.

Possible preventive effect of high doses of folic acid for isolated hypospadias: a national population-based case-control study.

Hypospadias is a common structural birth defect (congenital abnormality) of the male genital organ. The objective of this study was to test the hypothesis regarding the possible preventive effect of folic acid for isolated hypospadias (IH). Folic acid use was compared in 3,038 cases with IH and 24,814 male controls without any defects in the national population-based Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996. In Hungary only one kind of folic acid tablet, containing 3 mg/tablet was available during the study period. Hungarian obstetricians recommended daily use of 1-3 tablets, that is, 3-9 mg of folic acid during pregnancy; the estimated daily dose was 5.7 or 5.6 mg in the mothers of cases with IH and controls, respectively. Of 3,038 mothers of cases 1,474 (48.5%) were supplemented with high doses of folic acid during pregnancy and 13,509/24,814 mothers of controls (54.9%) as reference were supplemented at this level as well (OR 95% CI: 0.79, 0.73-0.85). If only medically recorded folic acid use in the critical period of IH was evaluated, the preventive effect was more apparent (OR 95% CI: 0.36, 0.32-0.41). The intake of folic acid among mothers of infants with severe IH was lower than among mothers of infants with mild IH, suggesting a dose-response relationship. In conclusion, this study suggests that high doses of folic acid are associated with a reduced risk of IH. However, this analysis was based on observational data; therefore, confirmation in a well-controlled study is needed.

Risk factors in the origin of congenital left-ventricular outflow-tract obstruction defects of the heart: a population-based case-control study.

The aim of our project was to study possible etiological factors in the origin of congenital heart defects (CHDs) because in the majority of patients the underlying causes are unclear. Cases with different CHD entities as homogeneously as possible were planned for evaluation in the population-based large data set of the Hungarian Case Control Surveillance of Congenital Abnormalities. Dead or surgically corrected 302 live-born cases with different types of left-ventricular outflow tract obstructive defects (LVOT, i.e., valvular aortic stenosis 76, hypoplastic left heart syndrome 76, coarctation of the aorta 113, and other congenital anomalies of aorta 32) were compared with 469 matched controls, 38,151 controls without any defects, and 20,750 malformed controls with other isolated defects. Medically recorded pregnancy complications and chronic diseases were evaluated based on prenatal maternity logbooks, whereas acute diseases, drug treatments, and folic acid/multivitamin supplementation were analyzed both on the basis of retrospective maternal information and medical records. The results of the study showed the role of maternal diabetes in the origin of LVOT in general, while panic disorder was associated with a higher risk of hypoplastic left heart syndrome and ampicillin treatment with a higher risk of coarctation of the aorta (COA). High doses of folic acid had a protective effect regarding the manifestation of LVOT, particularly COA. In conclusion, only a minor portion of causes was shown in our study; thus, further studies are needed to understand better the underlying causal factors in the origin of LVOT.

Risk and protective factors in the origin of atrial septal defect secundum--national population-based case-control study.

The aim of this study was to assess the risk factors in the origin of lethal or surgically corrected isolated atrial septal defect secundum. The population-based Hungarian Case-Control Surveillance of Congenital Abnormalities (conducted between 1980 and 1996) comprised 472 atrial septal defect secundum cases, 678 matched controls and 38,151 available controls without any defects; in addition, 21,022 malformed controls with other isolated defects. Medically recorded chronic disorders in the prenatal maternity logbook were evaluated, while acute maternal diseases, drug treatments and pregnancy supplements were analyzed on the basis of both prospective medically recorded data and retrospective maternal information. Acute pelvic inflammatory disease, paroxysmal supraventricular tachycardia and phenolphthalein treatment due to severe constipation of mothers were shown to contribute to the development of atrial septal defect secundum of their children. High doses of folic acid in early pregnancy had positively influenced a minor part of isolated atrial septal defect secundum in foetuses. In conclusion, the obvious genetic predisposition for atrial septal defect secundum is connected with maternal paroxysmal supraventricular tachycardia and triggered by acute pelvic inflammatory diseases and phenolphthalein treatment, while the manifestation of atrial septal defect secundum can be reduced by high doses of folic acid supplementation in early pregnancy.

Risk and protective factors in the origin of conotruncal defects of heart--a population-based case-control study.

Congenital heart defect (CHD) cases have been evaluated together as a group in some previous epidemiological studies. However, different CHD entities have different etiologies, and the underlying causes are unclear in the vast majority of patients. Thus the aim of this study was to analyze the possible association of different maternal diseases with the risk of four types of conotruncal defects (CTD), that is, truncus arteriosus, d-transposition of the great arteries, tetralogy of Fallot, and double-outlet right ventricle based on autopsy or surgical report diagnosis. Acute and chronic diseases with related drug treatments and peri-conceptual folic acid or multivitamin supplementations were compared in mothers of 598 CTD cases, of 902 matched controls, and 38,151 population controls without any defects, and with 20,896 malformed controls with other isolated non-cardiac defects in the population-based large dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities. Mothers who had medically recorded influenza and the common cold with secondary complications in the prenatal maternity logbook during the second and/or third gestational months were associated with a higher risk of CTD (OR with 95% CI: 2.22, 1.19-3.88). The common denominator of these maternal diseases may be high fever, which could be prevented by antifever therapies. On the other hand, high doses of medically recorded folic acid in early pregnancy were able to reduce the birth prevalence of CTD (OR with 95% CI: 0.54, 0.39-0.73), and this reduction was significant in transposition of the great arteries (0.46, 0.29-0.71) as well. In conclusion, high fever related maternal diseases may have a role in the origin of CTD, while high doses of folic acid in early pregnancy were able to reduce of CTD, particularly transposition of great vessels.

Isolated atrioventricular canal defects: birth outcomes and risk factors: a population-based Hungarian case-control study, 1980-1996.

BACKGROUND: The role of possible environmental factors in the origin of congenital heart defects is unclear in the vast majority of patients. The objective of this study was to describe the birth outcomes and risk factors in isolated atrioventricular canal defect (AVCD) cases. METHODS: Medically recorded birth outcomes, maternal age, parity, acute and chronic maternal diseases with related drug treatments and folic acid/multivitamin supplementation were evaluated in isolated AVCD cases. The diagnosis of AVCD was based on the autopsy report or surgical description in the population-based Hungarian Case-Control Surveillance of Congenital Abnormalities, between 1980 and 1996. RESULTS: The birth outcomes and exposures of 77 isolated AVCD cases were compared with 38,151 controls without defect. Mean gestational age at delivery (38.6 week) and birth weight (2992 g), rate of preterm birth (20.8%) and low birthweight (23.4%) of cases with a female excess (59.7%) differed significantly from the controls. Mothers of cases had higher parity, higher prevalence of conduction disorders/cardiac dysrhythmias and chronic hypertension. The high doses of folic acid in early pregnancy associated with a reduced rate of AVCD. CONCLUSIONS: Conduction disorders/cardiac dysrhythmias and chronic hypertension of mothers may have a role in the origin of AVCD, while high doses of folic acid in early pregnancy may reduce the risk of the development of AVCD. Birth Defects Research (Part A) 97:217-224, 2013. © 2013 Wiley Periodicals, Inc.

Birth outcomes of cases with isolated atrial septal defect type II--a population-based case-control study.

OBJECTIVES: In general, epidemiological studies have evaluated cases with congenital cardiovascular abnormalities together. The aim of this study is to describe the birth outcomes of cases with isolated/single atrial septal defect type II (ASD-II, i.e. only a fossa ovalis defect) after surgical correction or lethal outcome in the light of maternal sociodemographic data. DESIGN: Comparison of birth outcomes and maternal characteristics of cases with ASD-II and controls without defect. SETTING: The population-based Hungarian Case-Control Surveillance of Congenital Abnormalities. POPULATION: Hungarian newborn infants with or without ASD-II. METHODS: Medically recorded birth outcomes, maternal age and birth order were evaluated. Marital and employment status was based on maternal information. The lifestyle factors were analyzed in a subsample of mothers visited at home based on a personal interview with mothers and their close relatives, and the family consensus was accepted. MAIN OUTCOME MEASURES: Mean gestational age at delivery and birthweight, rate of preterm birth and low birthweight, maternal age, birth order, marital and employment status. RESULTS: The evaluation of 471 cases with ASD-II and 38,151 controls without any defects showed a female excess in cases with ASD-II, having shorter gestational age and lower mean birthweight, and thus a higher rate of preterm births and low birthweight. CONCLUSIONS: Intrauterine growth restriction and shorter gestational age were found in cases with ASD-II, particularly in female children. These factors may have a general developmental process in which there was not closure of the foramen ovale, thus echocardiographic screening of these babies might be of value.

Vitamin D and pre-eclampsia: original data, systematic review and meta-analysis.

BACKGROUND/AIMS: Vitamin D may protect from pre-eclampsia through influences on immune modulation and vascular function. To evaluate the role of vitamin D in the development of pre-eclampsia, we conducted a systematic review and meta-analysis including novel data from 2 large-scale epidemiological studies. METHODS: PubMed, EMBASE and the Cochrane Central Register of Controlled Trials were searched for prospective observational studies of association between vitamin D supplementation or status (measured by maternal 25-hydroxyvitamin D, 25(OH)D) with a subsequent risk of pre-eclampsia, or randomised controlled trials using vitamin D supplementation to prevent pre-eclampsia. The Hungarian Case-Control Surveillance of Congenital Abnormalities (HCCSCA) and the Avon Longitudinal Study of Parents and Children (ALSPAC) were included in meta-analyses with published studies. RESULTS: Mothers receiving vitamin D supplementation earlier in pregnancy had lower odds of pre-eclampsia [pooled odds ratios (OR) 0.81 and 95% confidence interval (CI) 0.75-0.87, p = 2.4 × 10(-8), 2 studies] in the meta-analysis of published studies with HCCSCA. The meta-analysis of published studies with ALSPAC suggested an association between higher serum 25(OH)D levels and a reduced risk of pre-eclampsia (pooled OR 0.52 and 95% CI 0.30-0.89, p = 0.02, 6 studies). Randomised trials of supplementation were suggestive of protective association (pooled OR 0.66 and 95% CI 0.52-0.83, p = 0.001, 4 studies). CONCLUSIONS: This study suggests that low maternal serum 25(OH)D concentrations increase pre-eclampsia risk and that vitamin D supplementation lowers this risk. The quality of evidence is insufficient to determine a causal association, which highlights the need for adequately powered clinical trials.

Vitamin supply in pregnancy for prevention of congenital birth defects.

PURPOSE OF REVIEW: After the short summary of history of primary prevention of neural tube defects by folic acid or folic acid-containing multivitamin supplementation during the periconception period, the three main unsolved problems are highlighted. RECENT FINDINGS: Both intervention trials and observational studies confirmed that this new primary preventive method is effective - beyond the prevention of neural-tube defects - in the reduction of the most common structural birth defects: congenital cardiovascular abnormalities. Nevertheless, this important progress in the field of congenital abnormalities is not appreciated appropriately. The periconception supplementation of both folic acid alone and folic acid-containing multivitamin is useful; however, the available data indicate the higher efficacy of multivitamins in the primary prevention of neural-tube defects and congenital cardiovascular abnormalities. The optimal dose of folic acid is not known though this knowledge would be necessary from both a scientific and practical aspect. SUMMARY: Periconception folic acid or folic acid-containing multivitamin supplementation has resulted in a breakthrough in the primary prevention of neural-tube defects, cardiovascular abnormalities and probably some other defects; however, extra efforts are necessary to eliminate folic acid or folic acid-containing multivitamin preventable congenital abnormalities.

Association between uterus uni/bicornis in pregnant women and postural deformities in their offspring.

OBJECTIVE: The objective of the investigation was to study the possible association between uterus uni- or bicornis in pregnant women and structural birth defects (ie, congenital abnormalities) in their offspring. STUDY DESIGN: There were 22,843 cases with congenital abnormality recorded in the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996. These subjects were matched to 38,151 controls without any defect. Prevalence of medically recorded uterus uni/bicornis in the prenatal maternity logbook in the mothers of subjects with different congenital abnormalities and of their matched controls without any defect were compared. RESULTS: Fifty-seven (0.25%) subjects and 67 (0.18%) controls had mothers with uterus uni/bicornis. There was a significant association of uterus uni/bicornis in pregnant women with a higher risk of total group of congenital abnormalities (adjusted odds ratio, 1.5; 95% confidence interval, 1.1-2.2) explained mainly by a significantly higher risk of clubfoot and particularly postural deformity association in their children (adjusted odds ratio, 4.7; 95% confidence interval, 2.4-9.1). CONCLUSION: Pregnant women with a uni/bicornis uterus have a significantly higher risk of clubfoot and postural deformity association.

Chronic hypertension in pregnancy.

PURPOSE OF REVIEW: Chronic hypertension is frequent in pregnant women as well. The objective of this review is to evaluate the maternal characteristics, pregnancy complications and birth outcomes including congenital abnormalities of pregnant women with chronic hypertension by reviewing the results of published studies and mainly the data of the population-based data set of the Hungarian Case-Control Surveillance System of Congenital Abnormalities. A second aim of the review is to examine the efficacy of antihypertensive drug treatments in the reduction of pregnancy-associated risks in women with chronic hypertension. RECENT FINDINGS: Pregnant women with treated chronic hypertension had a higher risk - beyond the well known pre-eclampsia and low birthweight newborns - of threatened abortion and preterm delivery, placental disorders and gestational diabetes. In addition a higher risk of hypospadias in one and of esophageal atresia/stenosis in another study was found in the children of pregnant women with chronic hypertension. These latter findings are signals which need confirmation or rejection in other studies. SUMMARY: The present antihypertensive treatments do not neutralize the harm of severe chronic hypertension in pregnant women and in their offspring, thus it is necessary to introduce more effective drug combinations for the treatment of pregnant women with severe chronic hypertension.

Periconceptional folic acid-containing multivitamin supplementation for the prevention of neural tube defects and cardiovascular malformations.

The prevention of neural tube defects with periconceptional folic acid or folic acid-containing multivitamin supplementation is accepted by the scientific community; here the possible prevention of cardiovascular malformations is discussed. The aim of this presentation is to show the main findings of trials and studies that resulted in the prevention of neural tube defects and particularly cardiovascular malformations by folic acid-containing multivitamins or folic acid supplementation in order to stimulate the incorporation of folic acid-containing multivitamins or folic acid in the prevention of cardiovascular malformations.

Prevention of neural-tube defects with periconceptional folic acid, methylfolate, or multivitamins?

BACKGROUND/AIMS: To review the main results of intervention trials which showed the efficacy of periconceptional folic acid-containing multivitamin and folic acid supplementation in the prevention of neural-tube defects (NTD). METHODS AND RESULTS: The main findings of 5 intervention trials are known: (i) the efficacy of a multivitamin containing 0.36 mg folic acid in a UK nonrandomized controlled trial resulted in an 83-91% reduction in NTD recurrence, while the results of the Hungarian (ii) randomized controlled trial and (iii) cohort-controlled trial using a multivitamin containing 0.8 mg folic acid showed 93 and 89% reductions in the first occurrence of NTD, respectively. On the other hand, (iv) another multicenter randomized controlled trial proved a 71% efficacy of 4 mg folic acid in the reduction of recurrent NTD, while (v) a public health-oriented Chinese-US trial showed a 41-79% reduction in the first occurrence of NTD depending on the incidence of NTD. CONCLUSIONS: Translational application of these findings could result in a breakthrough in the primary prevention of NTD, but so far this is not widely applied in practice. The benefits and drawbacks of 4 main possible uses of periconceptional folic acid/multivitamin supplementation, i.e. (i) dietary intake, (ii) periconceptional supplementation, (iii) flour fortification, and (iv) the recent attempt for the use of combination of oral contraceptives with 6S-5-methytetrahydrofolate (methylfolate), are discussed. Obviously, prevention of NTD is much better than the frequent elective termination of pregnancies after prenatal diagnosis of NTD fetuses.