Genetic-epidemiologic study of omphalocele and gastroschisis: evidence for heterogeneity

Prevalence rates study of selected isolated non-Mendelian congenital anomalies in the Hutterite population of Alberta, 1980-2016

A study of the prevalence rates for selected isolated non-Mendelian congenital anomalies in the Hutterite Brethren of Alberta, Canada was undertaken to further examine longitudinal data in this isolated community that was last reported in 1985 (Lowry et al., 1985), although there are numerous publications on recessive disorders (Boycott et al., 2008; Triggs-Raine et al., 2016). Cases were ascertained from the Alberta Congenital Anomaly Surveillance System for the years 1997-2016. Since our initial results showed some surprising findings in the Hutterite Brethren, such as zero cases of spina bifida, cleft lip and palate, gastroschisis, and omphalocele, and a significant excess of cases with hypospadias, we extended the study to prior years (1980-1996) for selected anomalies. For the extended study period (1980-2016), there was a significant increased prevalence of hypospadias, tetralogy of Fallot and tricuspid atresia in the Hutterite population, and although not statistically significant, zero cases of cleft lip with cleft palate, gastroschisis and omphalocele were confirmed. Further research is needed to determine the precise effects of rural environmental exposures, lifestyle factors, and genetic associations for selected multifactorial congenital anomalies.

Insights into the etiology and embryology of gastroschisis

The development of gastroschisis has long remained an area of interest and controversy. Successive theories about its pathogenesis are herein reviewed and discussed. Two historical assumptions, that omphalocele results from a persistent umbilical hernia, and that gastroschisis does not involve the umbilical cord, are dismissed. Therefore, one can envision gastroschisis for what it is, i.e. a ruptured physiological hernia. The causal agents for this intrauterine accident to occur are yet to be determined. Further bowel damage and complications can be explained by the mesenteric insult.

A clinical-pathogenetic approach on associated anomalies and chromosomal defects supports novel candidate critical regions and genes for gastroschisis

BACKGROUND

Gastroschisis has been assumed to have a low rate of syndromic and primary malformations. We aimed to systematically review and explore the frequency and type of malformations/chromosomal syndromes and to identify significant biological/genetic roles in gastroschisis.

METHODS

Population-based, gastroschisis-associated anomalies/chromosomal defects published 1950-2018 (PubMed/MEDLINE) were independently searched by two reviewers. Associated anomalies/chromosomal defects and selected clinical characteristics were subdivided and pooled by race, system/region, isolated, and associated cases (descriptive analysis and chi-square test were performed). Critical regions/genes from representative chromosomal syndromes including an enrichment analysis using Gene Ontology Consortium/Panther Classification System databases were explored. Fisher's exact test with False Discovery Rate multiple test correction was performed.

RESULTS

Sixty-eight articles and 18525 cases as a base were identified (prevalence of 17.9 and 3% for associated anomalies/chromosomal defects, respectively). There were 3596 associated anomalies, prevailing those cardiovascular (23.3%) and digestive (20.3%). Co-occurring anomalies were associated with male, female, American Indian, Caucasian, prenatally diagnosed, chromosomal defects, and mortality (P < 0.00001). Gene clusters on 21q22.11 and 21q22.3 (KRTAP), 18q21.33 (SERPINB), 18q22.1 (CDH7, CDH19), 13q12.3 (FLT1), 13q22.1 (KLF5), 13q22.3 (EDNRB), and 13q34 (COL4A1, COL4A2, F7, F10) were significantly related to biological processes: blood pressure regulation and/or vessel integrity, angiogenesis, coagulation, cell-cell and/or cell-matrix adhesion, dermis integrity, and wound healing (P < 0.05).

CONCLUSIONS

Our findings suggest that gastroschisis may result from the interaction of several chromosomal regions in an additive manner as a pool of candidate genes were identified from critical regions supporting a role for vascular disruption, thrombosis, and mesodermal deficiency in the pathogenesis of gastroschisis.

Familial occurrence of gastroschisis: a population-based overview on recurrence risk, sex-dependent influence, and geographical distribution

PURPOSE

There is uncertainty over whether familial recurrences in gastroschisis might be higher. Moreover, scant information is available regarding its sociodemographic features. We aim to explore the recurrence risk, sex-dependent influence, and geographical distribution of familial gastroschisis.

METHODS

A systematic review of the literature and data extraction from population-based studies published 1970-2017 (PubMed/MEDLINE) was independently performed by two reviewers. Familial ocurrence of gastroschisis, whereas sociodemographic features from 11 studies were pooled including 862 probands as a base. A descriptive analysis and Chi-square test were performed.

RESULTS

Twenty-four probands had a positive family history of gastroschisis including 49 affected family members, for a recurrence risk of 5.7 and 3% adjusted for proband. Siblings' recurrence was 4.3%. Sex-dependent influence analysis (n = 879, from three studies) evidenced an increased susceptibility to gastroschisis in males (2.5%) compared to females (1.3%) adjusted for proband. Heterogeneity was identified by Fisher's exact test (P = 0.023).

CONCLUSION

Our findings support a greater liability attributable to familial factors on gastroschisis along with significant information for family and prenatal counseling. We suggest that future studies should include for a more accurate account for both familial and environmental confounding factors to uncover relatives and environmental exposures that more limited family histories may have missed.

Evaluation of familial factors in a Mexican population-based setting with gastroschisis: Further evidence for an underlying genetic susceptibility

PURPOSE

To evaluate the occurrence of gastroschisis attributable to familial factors in a Mexican population-based setting.

METHODS

A descriptive study was performed among gastroschisis cases born from 2010 through 2016 at Tijuana General Hospital (Baja California, Mexico) to generate multigenerational pedigrees.

RESULTS

There were 87 gastroschisis cases from 57,217 live births. Six probands (6.9%) had another affected family member. Two half-siblings, a set of monozygotic twins, a mother-and-daughter occurrence, a distant paternal cousin and a distant maternal uncle were identified. Sibling recurrence was 5.5%. From 174 males and 153 females studied (n=327, involving 180 nuclear families), sex-dependent influence analysis evidenced an increased susceptibility to gastroschisis in males (3.2%) compared to females (1.8%) with an overall of 2.5% adjusted for proband.

CONCLUSIONS

Our results provide a greater liability attributable to familial factors on gastroschisis. In spite of the predominant sporadic occurrence, underlying genetic susceptibility and environmental influences point to a complex interplay between genes and environmental factors in gastroschisis.

LEVEL OF EVIDENCE

Level IV.

Self-reported maternal cigarette smoke exposure during the periconceptional period and the risk for omphalocoele

BACKGROUND

We investigated whether maternal exposure to cigarette smoke was associated with omphalocoele and whether periconceptional folic acid modified the association.

METHODS

 : We analysed data from the National Birth Defects Prevention Study on omphalocoele case (n = 301) and control (n = 8135) mothers for infants born from 1997 through 2007. Mothers who reported active smoking or exposure to second-hand smoke during the periconceptional period (1 month before conception to 3 months after) were considered exposed. Those who reported use of folic acid supplements during the same period were considered supplement users. Odds ratios and 95% confidence intervals were estimated using multivariable logistic regression adjusted for alcohol use, preconception body mass index, and race/ethnicity.

RESULTS

One hundred fifteen (38.2%) case and 2592 (31.9%) control mothers reported exposure to cigarette smoke during the periconceptional period. Adjusted odds ratios [95% confidence intervals] were 1.19 [0.94, 1.53] for any smoke exposure, 0.87 [0.54, 1.40] for active smoking, 1.38 [1.00, 1.90] for second-hand smoke exposure, and 1.16 [0.80, 1.67] for both exposures combined. No dose-response relationship was observed. Folic acid-containing supplements did not reduce the risk for omphalocoele among women with active or second-hand smoke exposure.

CONCLUSIONS

Self-reported active maternal smoking, with or without exposure to second-hand smoke, during the periconceptional period was not associated with omphalocoele. In contrast, there was a possible association with periconceptional exposure to second-hand smoke.

Folate and vitamin B12-related genes and risk for omphalocele

Both taking folic acid-containing vitamins around conception and consuming food fortified with folic acid have been reported to reduce omphalocele rates. Genetic factors are etiologically important in omphalocele as well; our pilot study showed a relationship with the folate metabolic enzyme gene methylenetetrahydrofolate reductase (MTHFR). We studied 169 non-aneuploid omphalocele cases and 761 unaffected, matched controls from all New York State births occurring between 1998 and 2005 to look for associations with single nucleotide polymorphisms (SNPs) known to be important in folate, vitamin B12, or choline metabolism. In the total study population, variants in the transcobalamin receptor gene (TCblR), rs2232775 (p.Q8R), and the MTHFR gene, rs1801131 (c.1298A>C), were significantly associated with omphalocele. In African-Americans, significant associations were found with SNPs in genes for the vitamin B12 transporter (TCN2) and the vitamin B12 receptor (TCblR). A SNP in the homocysteine-related gene, betaine-homocysteine S-methyltransferase (BHMT), rs3733890 (p.R239Q), was significantly associated with omphalocele in both African-Americans and Asians. Only the TCblR association in the total population remained statistically significant if Bonferroni correction was applied. The finding that transcobalamin receptor (TCblR) and transporter (TCN2) SNPs and a BHMT SNP were associated with omphalocele suggests that disruption of methylation reactions, in which folate, vitamin B12, and homocysteine play critical parts, may be a risk factor for omphalocele. Our data, if confirmed, suggest that supplements containing both folic acid and vitamin B12 may be beneficial in preventing omphaloceles.

Are abdominal wall defects and external genitalia anomalies randomly expressed in some families?

Familial cases of isolated abdominal wall defects with variable expressivity in more than one generation have rarely been observed. We report four affected individuals within a small three-generation family with either variable non-syndromic abdominal wall defects or external genital anomalies. We discuss the possible transmission of non-syndromic abdominal wall defects. It could be hypothesized that similar developmental defects may result in anomalies like hypospadias in males or developmental anomalies of the labia minora or labia majora in females.

Familial recurrence of gastroschisis: literature review and data from the population-based birth registry "Mainz Model"

BACKGROUND

Familial forms of gastroschisis are considered rare. A search for these forms in a population-based birth registry in 1993 found a recurrence risk of 3.5% among first-degree relatives. Since then, similar investigations in population-based registries have led to contradictory results.

METHODS

A search of the population-based birth registry "Mainz Model" for familial cases of gastroschisis and a systematic review of the literature were performed.

RESULTS

The Mainz Model database yielded 1 familial recurrence out of 27 gastroschisis cases. From the literature, 37 affected families could be retrieved. Among 412 gastroschises from population-based registries, 10 familial recurrences have been found. These translate into a recurrence risk of 2.4%, with a strong tendency toward underestimation.

CONCLUSION

The existing data support the hypothesis that familial recurrence of gastroschisis is much more likely than previously thought.

Gastroschisis with Hirschsprung's disease: a therapeutic dilemma

The authors report a case of a neonate with gastroschisis, which, after repair, was further complicated by the diagnosis of Hirschsprung's disease. The authors discuss the diagnostic and management dilemmas posed by the coexistence of these two conditions for the clinician.

Abdominal wall defects: autopsy findings of distinct groups suggest different pathogenetic mechanisms

Central and lateral abdominal wall defects are probably distinct and likely arise from different pathogenetic mechanisms. An autopsy study was done using data from a total of 45 central and lateral abdominal wall defect cases to evaluate if they are indeed separate entities and to suggest possible mechanisms involved in their formation. Central defects were found to be statistically different from lateral defects; malformations that co-existed with central defects were mainly bilateral and internal and also involved "inferior" organs in relation to fetal-embryonal blood flow. Patients with lateral defects were more often female, and their coexistent defects were usually unilateral and external, with only 1 defect occurring in an "inferior" organ. These results indicate mechanisms of a vascular perfusion deficit for the majority of the central defects and of external disruption for the lateral defects.

Structural birth defects associated with omphalocele and gastroschisis, Hawaii, 1986-2001

There is limited information on the specific structural birth defects associated with the abdominal wall defects (AWD) omphalocele and gastroschisis, particularly which defects occur with the AWD at greater than expected rates (rates among all infants and fetuses with birth defects other than the AWD). Using data from a population-based birth defects registry in Hawaii, this study calculated the rates for 48 specific structural birth defects among the AWD and compared these rates to the expected rates. There were 60 cases of omphalocele, 96 cases of gastroschisis, and 12,161 infants and fetuses with structural birth defects excluding the AWD among deliveries during 1986-2001. For omphalocele, higher than expected rates were found for 23 (47.9%) of the defects. These involved defects of a variety of organ systems. For gastroschisis, higher than expected rates were found for 8 (16.7%) of the defects, mainly neural tube defects (NTD) and specific defects of the orofacial and gastrointestinal system and the genital and urinary system. Both omphalocele and gastroschisis had elevated rates for NTD, intestinal atresia/stenosis, malrotation of intestines, obstructive genitourinary defects and limb reduction deformities. Certain specific structural birth defects occurred more often than expected with the AWD. The associated birth defects tended to vary between omphalocele and gastroschisis, although there were a few similarities. Due to the small number of cases, further research involving larger amounts of data are warranted.

Neonatal haemochromatosis associated with gastroschisis

We describe, to our knowledge, the first case of progressive neonatal liver failure due to neonatal haemochromatosis (NH) occurring in an infant with a gastroschisis and review the literature regarding these two conditions. A 1,665 g male infant with antenatally diagnosed gastroschisis was born with a severe coagulopathy, anaemia, thrombocytopenia, hypoglycaemia and jaundice. He developed progressive liver failure, complicated by necrotising enterocolitis. Serum ferritin was elevated at 1,459 microg/L. He died on day 40 and a limited post-mortem examination confirmed significant hepatic siderosis with fibrosis and cholestasis, and siderosis of the pancreas. Although no genetic aetiology for gastroschisis has been identified, an occasional inherited tendency has been observed. There is also evidence to support an autosomal recessive inheritance in NH.

Development of gastroschisis: review of hypotheses, a novel hypothesis, and implications for research

Gastroschisis, a ventral body wall defect, is a continuing challenge and concern to researchers, clinicians, and epidemiologists seeking to identify its cause(s) and pathogenesis. Concern has been renewed in recent years because, unlike most other birth defects, rates of gastroschisis are reportedly increasing in many developed and developing countries. No tenable explanation or specific causes have been identified for this trend. Rates of gastroschisis are particularly high among pregnancies of very young women. Such an intriguing association, not observed to this degree with other birth defects, may afford clues to the defect's cause. Understanding the causes of gastroschisis may provide insight to the defect's origin. In pursuing such causal studies, it would be helpful to understand the embryogenesis of gastroschisis. To date, four main embryologic hypotheses have been proposed: (1) Failure of mesoderm to form in the body wall; (2) Rupture of the amnion around the umbilical ring with subsequent herniation of bowel; (3) Abnormal involution of the right umbilical vein leading to weakening of the body wall and gut herniation; and (4) Disruption of the right vitelline (yolk sac) artery with subsequent body wall damage and gut herniation. Although based on embryological phenomena, these hypotheses do not provide an adequate explanation for how gastroschisis would occur. Therefore, we propose an alternative hypothesis, based on well described embryonic events. Specifically, we propose that abnormal folding of the body wall results in a ventral body wall defect through which the gut herniates, leading to the clinical presentation of gastroschisis. This hypothesis potentially explains the origin of gastroschisis as well as that of other developmental defects of the ventral wall.

Prenatal genomic profiling of abdominal wall defects through comparative genomic hybridization: perspectives for a new diagnostic tool

OBJECTIVES

To describe the molecular analysis through comparative genomic hybridization (CGH) of fetuses with gastroschisis, and to observe if this technique could improve the resolution of the conventional cytogenetic techniques.

METHODS

Amniotic analysis of fetuses with gastroschisis, using both conventional (G-banding) and molecular (CGH) cytogenetics assays.

RESULTS

All of the seven fetuses studied displayed a normal G-band karyotype. Six fetuses displayed a normal disomic profile through CGH and one sample has displayed ish cgh enh 3q26-->qter result (ICSN). The fetus with this imbalance of chromosome 3 was re-classified as a ruptured omphalocele, instead of gastroschisis, after birth.

CONCLUSIONS

The molecular investigation through CGH technique can improve the resolution of the conventional karyotye analysis in cases of abdominal wall defects.

Syndromes and Disorders Associated with Omphalocele (III): Single Gene Disorders, Neural Tube Defects, Diaphragmatic Defects and Others

Omphalocele can be associated with single gene disorders, neural tube defects, diaphragmatic defects, fetal valproate syndrome, and syndromes of unknown etiology. This article provides a comprehensive review of omphalocele-related disorders: otopalatodigital syndrome type II; Melnick-Needles syndrome; Rieger syndrome; neural tube defects; Meckel syndrome; Shprintzen-Goldberg omphalocele syndrome; lethal omphalocele-cleft palate syndrome; cerebro-costo-mandibular syndrome; fetal valproate syndrome; Marshall-Smith syndrome; fibrochondrogenesis; hydrolethalus syndrome; Fryns syndrome; omphalocele, diaphragmatic defects, radial anomalies and various internal malformations; diaphragmatic defects, limb deficiencies and ossification defects of skull; Donnai-Barrow syndrome; CHARGE syndrome; Goltz syndrome; Carpenter syndrome; Toriello-Carey syndrome; familial omphalocele; Cornelia de Lange syndrome; C syndrome; Elejalde syndrome; Malpuech syndrome; cervical ribs, Sprengel anomaly, anal atresia and urethral obstruction; hydrocephalus with associated malformations; Kennerknecht syndrome; lymphedema, atrial septal defect and facial changes; and craniosynostosismental retardation syndrome of Lin and Gettig. Perinatal identification of omphalocele should alert one to the possibility of omphalocele-related disorders and familial inheritance and prompt a thorough genetic counseling for these disorders.

Caring for the newborn with an omphalocele

An omphalocele, a ventral defect of the umbilical ring resulting in herniation of the abdominal viscera, is one of the most common congenital abdominal wall defects seen in the newborn. Omphaloceles occur in 1 in 3000 to 10,000 live births. Associated malformations such as chromosomal, cardiac, or genitourinary abnormalities are common. Postnatal management includes protection of the herniated viscera, maintenance of fluids and electrolytes, prevention of hypothermia, gastric decompression, prevention of sepsis, and maintenance of cardiorespiratory stability. A primary or staged closure approach may be used to repair the defect. Some giant omphaloceles require a skin flap or nonoperative management approach, hoxvever. Immediate postoperative complications, usually related to significant changes in intra-abdominal pressures, include compromise of interior venous blood return and hemodynamic and respiratory instability due to diaphragmaric elevation. Complications occur more frequently with giant defects. Potential short-term complications include necrotizing enterocolitis, prolonged ileus, and respiratory distress. Long-term complications include parenteral nutrition dependence, gastroesophageal reflux, parenteral nutrition-related liver disease, feeding intolerance, and neurodevelopmental delay. Overall, advances in surgical therapies and nursing care have improved outcomes for infants with omphaloceles; survival rates for those with isolated omphaloceles are reported at 75 to 95 percent. Infants with associated anomalies and giant omphaloceles have the poorest outcomes.

Comparison of trends in gastroschisis and prenatal illicit drug use rates

Gastroschisis rates have been increasing over time, and gastroschisis risk is elevated in women of young maternal age. Similar patterns were reported for prenatal illicit drug use in Hawaii. Cases of gastroschisis and prenatal use of methamphetamine, cocaine, or marijuana among deliveries in Hawaii during 1986-2002 were identified from a common registry. The pattern of gastroschisis rates by maternal age and time period was compared to the pattern of prenatal illicit drug use rates. The prenatal marijuana use rate among gastroschisis cases was significantly greater than among the total population. Prenatal methamphetamine and cocaine rates were not significantly elevated among gastroschisis cases. The gastroschisis rate was highest among the youngest maternal age group, then declined with increasing maternal age. Only prenatal marijuana use demonstrated a similar pattern, but the ratio of the gastroschisis rate to the prenatal marijuana use rate declined with increasing maternal age. The gastroschisis rate increased during the 17-yr period. Both methamphetamine and marijuana demonstrated similar annual trends; however, the ratio of the gastroschisis rates to the illicit drug use rates varied greatly for the 2 drugs over time. The results of this investigation suggest that prenatal illicit drug use of methamphetamine, cocaine, and marijuana may not play a major role in explaining the increased risk of gastroschisis among younger mothers and the annual increases that have been reported.

Management of neonates with large abdominal wall defects and undescended testis

OBJECTIVES

To assess, in a retrospective study, the outcome of different treatment modalities in newborns with undescended testes secondary to large abdominal wall or diaphragmatic defects. Large abdominal and diaphragmatic defects are known to be associated with cryptorchidism, yet the reported incidence varies widely.

METHODS

A total of 112 neonates with large abdominal wall or diaphragmatic defects were treated from 1981 to 2005. Of the 55 male patients in this series, 9 (16.4%) presented with abdominal testes and 4 had an extra-abdominal testis (7.3%).

RESULTS

The 2 patients undergoing primary orchiopexy had testes of normal size and in the normal position at last follow-up. In one of these patients in whom the testis was brought down to the internal inguinal ring, spontaneous descent occurred and the testis on the affected side was normal. The other patient required additional surgery and had an atrophic testis at last follow-up. In 1 patient with severe concomitant malformations, primary orchiectomy was performed. The 4 patients who did not receive initial treatment all lost their testes owing to atrophy.

CONCLUSIONS

The results of the present study have indicated that primary orchiopexy should be attempted in all cases of abdominal wall defects associated with abdominal cryptorchid testes because it yields better testicular salvage rates. In cases in which the spermatic cord is not long enough to place the testis into the scrotum, mobilization and fixation at the lowest site possible resulted in better outcomes than leaving the testis in the abdomen.

Increasing prevalence of gastroschisis in Utah

BACKGROUND

Recent studies provide conflicting information about gastroschisis prevalence trends. The authors proposed that prevalence of gastroschisis in live births has increased in Utah and that characteristics of these infants would provide clinically useful information about treatment and outcomes.

METHODS

Primary Children's Medical Center (PCMC) is the sole pediatric surgical referral hospital for Utah. The authors used both pediatric surgical and neonatal databases to identify gastroschisis cases at PCMC from 1971 through 2002. Only infants whose mothers had a primary residence in Utah were included. Individual charts were reviewed for infant characteristics for cases from 1998 through 2002. Utah Vital Statistics Reports were used to determine live birth rates and general infant and maternal characteristics.

RESULTS

Gastroschisis prevalence increased from 0.36 to 3.92 cases per 10,000 live births over 31 years (P < .001). Young maternal age, primigravida status, and tobacco use were associated risk factors. Using the time required to achieve full enteric feedings at targeted volume and caloric density as a measurement of outcome, we found no association between delivery mode or surgical closure type (primary or secondary) and time to full feedings. Higher birth weight was associated with decreased time to full feedings (P = .03).

CONCLUSIONS

Gastroschisis prevalence has increased 10-fold over the past 3 decades in Utah.

Mutations in PITX2 may contribute to cases of omphalocele and VATER-like syndromes

Omphalocele is a congenital anomaly with substantial morbidity. Rieger syndrome, an autosomal dominant disorder, is characterized by craniofacial abnormalities and abdominal wall defects. PITX2 mutations are etiologic in >40% of cases of Rieger syndrome. We demonstrate that the birth prevalence of omphalocele is significantly higher in Rieger syndrome than in the general population, with omphaloceles found in 0.03% in the Iowa newborn population and 4.3% of patients with Rieger syndrome. Our objective was to screen coding and conserved non-coding regions of PITX2 for mutations in 209 patients with omphalocele. We identified remarkable evolutionarily conserved regions by comparing the 3'UTR of Pitx2 in 13 vertebrate and 3 invertebrate species. No mutations changing the amino acid sequence were found within the omphalocele population. In one case of omphalocele with VATER-like additional anomalies, a three nucleotide deletion was found in the 3'UTR. This deletion was not seen in 1,186 controls. Also in the 3'UTR, we identified a single nucleotide polymorphism at a highly conserved residue. Our findings suggest additional studies of PITX2 conserved regions will be valuable. We also screened the omphalocele cases for mutations in exon 5 of the gene FLNA. Mutations in FLNA have been shown to cause a broad range of congenital malformations, including otopalatodigital syndrome type 2 in which a missense mutation occurring in exon 5 of FLNA results in omphalocele as part of the phenotype. We did not find any mutations in exon 5 of FLNA in 179 omphalocele cases studied.

Omphalocele and gastroschisis: An 18-year review study

PURPOSE

Using data from a single University Genetics Division practice, the authors sought to determine if gastroschisis is increasing in occurrence compared to omphalocele. Associated abnormalities were also examined. In addition, prenatal exposure to teratogens and other parameters were compared.

METHODS

All fetal and infant cases of omphalocele and gastroschisis seen in the University of South Florida Division of Genetics between January 2, 1982 and December 31, 1999 were retrieved through the database and analyzed through chart review.

RESULTS

There were 127 cases of omphalocele and 121 cases of gastroschisis. Ninety-three of the 127 probands with omphalocele had karyotype determinations and 20% were abnormal; for gastroschisis, 37 had cytogenetic studies and none had chromosomal anomalies. Seventy-six percent of the probands with omphalocele had associated abnormalities; twenty-three percent of the probands with gastroschisis, none of which were syndromic, had associated anomalies. The prematurity rate for omphalocele was 42% and mortality was 22%; for gastroschisis, the figures were 57% and 9%, respectively. There were no significant differences in teratogen exposure between the two groups. Familial cases of both defects occurred in < 4%, and the prevalence of dizygous twinning was increased in both groups. Mean maternal age was 21.8 years for the gastroschisis group, 27.2 years for the omphalocele group.

CONCLUSIONS

In this study, the number of cases of omphalocele and gastroschisis were similar, compared to the expected 3:2 ratio, suggesting an increase in the occurrence of gastroschisis. Cases with omphalocele had more syndromic and nonsyndromic anomalies, more chromosomal anomalies, a higher mortality rate, and older mothers.

Isolated Gastroschisis in Successive Siblings: A Case Report and Review of the Literature

BACKGROUND

Although gastroschisis occurring in siblings is rare, a number of cases have been reported. A variety of inheritance patterns and embryologic explanations have previously been suggested. Young maternal age appears to be a consistent risk factor.

CASE

At age 17 years, Melanie (pseudonym) presented at 36 weeks' gestation and delivered a boy affected by gastroschisis. This condition had not been noted at a 13-week prenatal ultrasound. At age 18 years, Melanie delivered a second son with gastroschisis. There was no history of gastroschisis or other congenital anomaly in either parent's family. Melanie denied the use of alcohol, cigarettes, street drugs, and medications. She has since delivered 2 healthy children.

CONCLUSION

There is a need for preconception counselling for women who have experienced a pregnancy complicated by gastroschisis, to discuss the low but possible risk of recurrence. Early ultrasound may allow for detection or reassurance.

Malformations in acardiac twins are consistent with reversed blood flow: liver as a clue to their pathogenesis

Because of the uncertainty concerning the origin of the malformations in the acardiac twin, its structure was studied to see if the malformations were random or with a pattern related to the twinning process. Included were 18 cases of dysmorphic twins in which an autopsy demonstrated a rudimentary or absent heart, and in which some polarity was evident. The organs and long bones with alterations were tabulated according to the embryonal-fetal circulation of blood from and to the placenta. Malformations were more often encountered in the superior limbs and organs; the number of altered organs decreased in a cranio-caudal direction. The liver was the exception being affected in 89% of the cases vs. an average of 54% for the other abdominal organs. As the liver lies first in the circulatory path from the placenta to the fetus, the pattern of the malformations was in accordance with the "twin reversed arterial perfusion sequence" (TRAP). The more frequent absence of distal bones (P = 0.0007) is compatible with reduced perfusion in each limb. The malformations found in the acardiac twins involved brain, esophagus and trachea, liver, other abdominal organs, diaphragm, vertebrae, limbs, anus, and omphalocele; vascular disruption may be the common pathogenesis for the acardiac twins as well as other dysmorphic infants with similar anomalies.

Omphalocele and gastroschisis in the state of New York, 1992-1999

BACKGROUND

Variations in the temporal distribution and risk factors for omphalocele and gastroschisis have been suggested although results have not been conclusive. This study examines the trend and risk factors for both conditions among live births in New York State.

METHODS

Analysis of surveillance data from the New York Congenital Malformation Registry for the years 1992-1999.

RESULTS

Five hundred and ninety-five (595) infants with either omphalocele (287) or gastroschisis (308) were identified. It appeared that the prevalence of gastroschisis was rising from 1992-1999, while prevalence of omphalocele was decreasing. Cases of gastroschisis were clustered among younger mothers while the maternal age distribution among omphalocele infants was U-shaped. As compared to Whites, Black infants were more likely to present with omphalocele (OR = 1.73; 95% confidence interval = 1.28-2.33) and Hispanic infants with gastroschisis (OR = 1.50; 95% CI = 1.12-2.00). For both anomalies, residents of rural New York were significantly at higher risk than those living in urban New York. Twenty-three chromosomal aberrations were detected, all among omphalocele babies. Infant survival was substantially greater among gastroschisis (92%) as compared to omphalocele newborn (81%)[p < 0.0001].

CONCLUSIONS

Prevalence of gastroschisis has been on the rise while that of omphalocele has been declining in New York State. Geographical and racial/ethnic variations were observed, further confirming the notion of different etiologies for the two congenital anomalies.

Prenatal management of gastroschisis: the place of the amnioexchange procedure

Gastroschisis is a malformation of the anterior abdominal wall that consists of a right paraumbilical defect with bowel loops bathed in the amniotic fluid. The survival rate is now greater than 90% and the prognosis relies mainly on morbidity attributable to bowel dysfunction. Recent research has examined gastrointestinal waste present in amniotic fluid that induces bowel toxicity and an inflammatory process. The amnioexchange procedure (changing the amniotic fluid regularly) involves a new therapeutic approach: reducing bowel injuries in the fetuses. This article shows that there is an inflammatory reaction in human gastroschisis and in the authors' model, and that the clinical and biological data plead for the practice of amnioexchange in human beings. A randomized, controlled study is now needed.

Abdominal wall defects

Survival for newborns with congenital abdominal wall defects (primarily omphalocele and gastroschisis) has improved, but controversy remains regarding etiology, anatomy and embryology, the role of prenatal diagnosis and mode of delivery, and initial management. A number of recent studies have added to our knowledge and understanding of several of these topics, while several others have raised questions regarding traditional initial management of these infants. Continued improvement in the survival of these infants can be anticipated with further understanding of the in utero and antepartum diagnosis and management of infants with these common congenital abnormalities.

Mutational analysis of the BMP-1 gene in patients with gastroschisis

BACKGROUND

Gastroschisis is a rare abdominal wall defect. Although the pathogenesis of gastroschisis is unknown, there is some evidence of the genetic etiology of gastroschisis. Recently, a functionally null deletion of the mouse bone morphogenic protein-1 (BMP-1) gene resulted in a phenotype that resembled a human neonate with gastroschisis. BMP-1 thus became the first potential candidate gene for gastroschisis.

METHODS

To explore this possibility the authors collected blood samples from 11 patients who had gastroschisis. Mutational analysis of exons 2 to 15 of the human BMP-1 gene was performed using genomic polymerase chain reaction, single-strand conformation polymorphism analysis and direct sequencing methods.

RESULTS

No mutation of the human BMP-1 gene was observed in any of these patients.

CONCLUSION

Although heterogeneous etiologies might be proposed for gastroschisis, our results provide further evidence of a nongenetic etiology for gastroschisis. J Pediatr Surg 36:885-887.

Epidemiology of abdominal wall defects, Hawaii, 1986-1997

The various types of abdominal wall defects are considered to differ in their etiologies, a hypothesis suggested by differences in their epidemiologies. This study examined the impact of selected demographic factors on abdominal wall defects (omphalocele, gastroschisis, and body stalk anomaly) included in a birth defects registry in Hawaii from 1986-1997. The total prevalence for the various defects were: omphalocele (2.76 per 10,000 births, 95% confidence interval (CI), 2.14-3.50), gastroschisis (3.01, 95% CI, 2. 36-3.77), and body stalk anomalies (0.32, 95% CI, 0.14-0.64). The prevalence increased over the 12-year period for both omphalocele (P = 0.052) and gastroschisis (P = 0.008). Women less than age 20 were at increased risk for a gastroschisis-affected pregnancy, while those age 40 and over were disproportionately more likely to have an omphalocele-affected pregnancy. Pacific Islanders had the lowest risk for omphalocele, whereas Far East Asians were least likely to have gastroschisis. Omphalocele rates were lower outside metropolitan Honolulu, while place of residence did not significantly impact gastroschisis risk. The 1-year survival rate was higher for gastroschisis than for omphalocele (88.5% and 70.7%, respectively), while none of the infants with body stalk anomalies was live-born. The results of this study tend to support the hypothesis of differing etiologies for the studied abdominal wall defects.

A 19-week-old fetus with craniosynostosis, renal agenesis and gastroschisis: case report and differential diagnosis

A case of a fetus affected with craniosynostosis, unilateral renal agenesis and gastroschisis is reported. The propositus was delivered on the 19th week of gestation for premature rupture of the membranes. Macroscopy showed turricephaly, shallow orbits, exophthalmos, hypertelorism, hypoplastic maxilla with relative mandibular prognathism and gastroschisis. Additional autopsy findings included a premature bilateral closure of the lambdoid suture and a unilateral renal agenesis. The nosological aspects of this fetus and the differential diagnosis of well-described craniosynostosis syndromes with characteristic craniofacial growth patterns (Crouzon syndrome, Jackson-Weiss syndrome, Apert syndrome, Saethre-Chotzen syndrome, Pfeiffer syndrome) are discussed.

Association of prenatal vascular disruptions with decreased maternal age

Disruptions of fetal structures can create a variety of congenital anomalies. Some apparent prenatal vascular disruptions associate strongly with decreased maternal age, and are rare with older mothers. This is well-documented for gastroschisis, but similar findings with hydranencephaly suggest a general phenomenon that may also involve porencephaly, septo-optic dysplasia, early body stalk disruptions, certain hemifacial anomalies, and other findings. Prenatal vascular disruption may be a common cause of congenital anomalies, but its nature is unknown, and obvious environmental confounders associated with decreased maternal age may have only relatively small contributions. A protective effect for pregnancies of older mothers also remains a possibility.

Impact of antenatal diagnosis on incidence and prognosis in abdominal wall defects

The authors review data from the Congenital Malformation Registry in South East Thames regarding fetal abdominal wall defects. Over 24 months, 80 cases were observed (40 gastroschisis, 40 exomphalos). Live-born infants with gastroschisis had few associated anomalies and an excellent prognosis (83% survival rate). Exomphalos is associated with an increased rate of life-threatening anomalies and chromosomal defects. The latter cases often are terminated prenatally. If these cases are excluded, the 1-year survival rate for liveborn infants with exomphalos is favorable (close to 80%). Fetuses in whom gastroschisis and exomphalos are identified by ultrasonography but who have no associated life-threatening chromosomal anomalies should have a favorable prognosis.

Familial gastroschisis: a case of mother-and son occurrence

Gastroschisis is a rare congenital abdominal wall anomaly with a pathogenesis and mode of transmission that are not completely understood. There are few published reports of familial gastroschisis and no reported case of vertical transmission. The authors report the first published case of a mother who had gastroschisis and gave birth to a son with gastroschisis, which supports a genetic etiology.

Omphalocele and gastroschisis in Europe: a survey of 3 million births 1980-1990. EUROCAT Working Group

A total of 732 cases of omphalocele and 274 cases of gastroschisis was registered in 21 regional registers in Europe (EUROCAT registers) during the period 1980-1990. The total prevalence rates were 2.52 per 10,000 for omphalocele and 0.94 per 10,000 for gastroschisis. There was significant heterogeneity in total prevalence rates among regions for omphalocele. Consistently higher than average total prevalence rates of omphalocele were found in the five centers of the British Isles. This was in large part linked to the association between omphalocele and neural tube defects. A significant female excess among the cases of omphalocele associated with neural tube defects, in comparison with an insignificant male excess for other cases of omphalocele, was observed. Geographical differences in the total prevalence of gastroschisis are partly explained by differences in maternal age distributions in the populations surveyed. Omphalocele was an isolated malformation in 46% of cases; gastroschisis was isolated in 79% of cases. The average birthweight and gestational age of both isolated and multiply malformed cases of both omphalocele and gastroschisis were low, especially for multiply malformed cases, and to a greater extent for isolated gastroschisis than for isolated omphalocele. Prenatal diagnosis leading to termination of pregnancy was reported in 33.2% of omphalocele and in 26.5% of gastroschisis cases, demonstrating the considerable impact of current prenatal screening programs. On the basis of clinical manifestations, epidemiologic characteristics, and the presence and type of additional malformations, omphalocele and gastroschisis can be considered heterogeneous conditions.

Monozygotic twins discordant for gastroschisis: case report and review of the literature of twins and familial occurrence of gastroschisis

We describe a pair of monozygotic (MZ) female twins discordant for gastrochisis. To our knowledge, this is the first such case reported. The zygosity was verified by DNA analysis using highly polymorphic microsatellites. There was no family history of gastroschisis. During pregnancy there was no suspicion of any exposure responsible for the malformation. The number of twin cases described so far does not allow any conclusion as to hereditary factors in the cause of gastroschisis, but the number of families reported with familial gastroschisis suggests that the recurrence risk is higher than previously thought.

Comparative epidemiology of selected midline congenital abnormalities

We present comparative epidemiologic characteristics of five congenital abnormalities that have been suggested to result from midline abnormal developmental disturbances: esophageal atresia with or without tracheoesophageal fistula (EA/TEF), imperforate anus with or without fistula (IA/F), omphalocele (OM), bladder exstrophy (BE), and diaphragmatic hernia (DH). The purpose was to assess the extent of epidemiologic similarities among these five defects. Data were collected as part of a population-based case-control study of infants with these defects born to mothers residing in Maryland, Washington, D.C., or Northern Virginia from 1980 through 1987. The estimated annual birth prevalences (per 10,000 live births) and 95% confidence intervals (CI) of these five defects were 0.40 (0.26-0.61) for BE, 1.34 (1.08-1.67) for OM, 1.59 (1.29-1.95) for DH, 2.11 (1.76-2.53) for EA/TEF, and 2.97 (2.55-3.46) for IA/F. The birth prevalence of IA/F and DH increased between 1980 and 1987. In contrast to the other four defects, DH showed a significant male preponderance (rate ratio 1.57, 95% CI 1.03-2.47), a significant white excess (rate ratio white:other, 1.56, 95% CI 1.00-2.48), and a lower proportion of multiple associated defects (30% vs. 46-61%). We concluded from this study that the descriptive epidemiology of diaphragmatic hernia is different from that of the other four defects. This finding may imply differences in etiologic and pathogenetic mechanisms underlying DH.