Familial occurrence of omphalocele suggesting sex-linked inheritance

Omphalocele: a review of common genetic etiologies

Omphalocele is one of the most common congenital defects in the anterior abdominal wall. The malformation is associated with various pathologies especially with chromosomal disorders. The developmental defect is observed in Congolese hospitals, but risk factors are not well precised on the published case reports, which are more often focused on management. We aim in this paper to make a review on the condition, insisting on the risk factors of omphaloceles mainly of those of genetic origins.

Genome-wide linkage and copy number variation analysis reveals 710 kb duplication on chromosome 1p31.3 responsible for autosomal dominant omphalocele

BACKGROUND

Omphalocele is a congenital birth defect characterised by the presence of internal organs located outside of the ventral abdominal wall. The purpose of this study was to identify the underlying genetic mechanisms of a large autosomal dominant Caucasian family with omphalocele.

METHODS AND FINDINGS

A genetic linkage study was conducted in a large family with an autosomal dominant transmission of an omphalocele using a genome-wide single nucleotide polymorphism (SNP) array. The analysis revealed significant evidence of linkage (non-parametric NPL = 6.93, p=0.0001; parametric logarithm of odds (LOD) = 2.70 under a fully penetrant dominant model) at chromosome band 1p31.3. Haplotype analysis narrowed the locus to a 2.74 Mb region between markers rs2886770 (63014807 bp) and rs1343981 (65757349 bp). Molecular characterisation of this interval using array comparative genomic hybridisation followed by quantitative microsphere hybridisation analysis revealed a 710 kb duplication located at 63.5-64.2 Mb. All affected individuals who had an omphalocele and shared the haplotype were positive for this duplicated region, while the duplication was absent from all normal individuals of this family. Multipoint linkage analysis using the duplication as a marker yielded a maximum LOD score of 3.2 at 1p31.3 under a dominant model. The 710 kb duplication at 1p31.3 band contains seven known genes including FOXD3, ALG6, ITGB3BP, KIAA1799, DLEU2L, PGM1, and the proximal portion of ROR1. Importantly, this duplication is absent from the database of genomic variants.

CONCLUSIONS

The present study suggests that development of an omphalocele in this family is controlled by overexpression of one or more genes in the duplicated region. To the authors' knowledge, this is the first reported association of an inherited omphalocele condition with a chromosomal rearrangement.

Twins with omphalocele in Denmark (1970-1989)

Seven pairs of twins, two monozygotic (MZ), two dizygotic (DZ), and three like-sex pairs of unknown zygosity are described. The twin pairs were all discordant for omphalocele except for one pair of conjoined twins. The 8 infants with omphalocele represent 3.1% of the 253 infants with omphalocele, ascertained in an almost complete nationwide data set of live- and stillborn infants with abdominal wall defects in two decades in Denmark (1970-1989). The occurrence of twins with omphalocele was not significantly different from the occurrence of twins in the Danish population in the same period. To our knowledge this is the first report of the occurrence of twins with omphalocele in a systematic nationwide epidemiological study.

Demographic and environmental risk factors for gastroschisis and omphalocele in the National Birth Defects Prevention Study

BACKGROUND

Primary prevention efforts for both gastroschisis and omphalocele are limited by the lack of known risk factors. Our objective was to investigate associations between potential maternal risk factors and gastroschisis and omphalocele within a large population-based sample of participants enrolled in the National Birth Defects Prevention Study (NBDPS).

METHODS

Demographic, health-related, and environmental exposure data from the NBDPS were collected from women with expected delivery dates between October 1997 and December 2003. Data were collected on 485 cases of gastroschisis, 168 cases of omphalocele, and 4967 controls.

RESULTS

Women who had offspring with gastroschisis were younger (adjusted odds ratio [AOR], 0.84; 95% confidence interval [CI], 0.81-0.86) and less likely to be black (AOR, 0.54; 95% CI, 0.34-0.85) than controls. They also were more likely to have smoked (AOR, 1.51; 95% CI, 1.12-2.03), taken ibuprofen (AOR, 1.61; 95% CI, 1.23-2.10), and consumed alcohol (AOR, 1.38; 95% CI, 1.06-1.79) than controls. Women who had offspring with omphaloceles were more likely to have consumed alcohol (AOR, 1.53; 95% CI, 1.04-2.25) and be heavy smokers (AOR, 4.26; 95% CI, 1.58-11.52) than controls.

CONCLUSIONS

Our results suggest a moderately increased risk of gastroschisis among women who used tobacco, alcohol, and ibuprofen during early pregnancy. A modestly elevated risk was observed for omphaloceles among women who used alcohol during the first trimester and among women who were heavy smokers.

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.

Characteristics and outcome of 90 cases of fetal omphalocele

OBJECTIVE

The aim of this study was to describe the outcome of a case series of fetuses with omphalocele.

METHODS

Ninety fetuses with omphalocele at the National Center for Fetal Medicine (NCFM) between January 1985 and January 2004 were followed from the time of prenatal diagnosis. Follow-up times ranged from 6 months to 17 years. Omphaloceles were subdivided into epigastric, central and hypogastric types based on their location on the abdominal wall.

RESULTS

There were 58 central and 32 epigastric omphaloceles. Abnormal karyotype was found in 40/58 (69%) of the central and in 4/32 (12.5%) of the epigastric omphaloceles. Trisomy 18 was the most frequent abnormality associated with omphalocele. Among the fetuses with normal karyotype, 89% of the central and 71% of the epigastric cases had other anomalies. 38 (66%) of the fetuses with central omphalocele were terminated and 12 (21%) died during pregnancy or after delivery. 11 (34%) of the fetuses with epigastric omphalocele were terminated and eight (25%) died during pregnancy or after delivery. Of the 90 cases followed from the time of diagnosis there were 21 (23%) survivals. Of eight survivals with central omphalocele, only two were considered healthy while six had other anomalies and/or substantially impaired development. Of 13 survivals with epigastric omphalocele, six were considered healthy and seven had other anomalies and/or substantial impairment.

CONCLUSIONS

Fetal central and epigastric omphaloceles may be different entities: central omphaloceles are more strongly associated with abnormal karyotype (69%) than are epigastric omphaloceles (12.5%). The outcome of fetuses with omphalocele is poor irrespective of the type of omphalocele, with only eight of the 90 (9%) being alive and healthy at present. The results emphasize the importance of identifying both those fetuses with a potentially good prognosis and favorable outcome and those which are likely to have a fatal outcome.

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.

Prenatal diagnosis of complicated abdominal wall defects

The accurate prenatal diagnosis of anterior abdominal wall defects is important because it affects patient management and prognosis. The pathophysiology of each defect leads to key characteristics that make it possible to differentiate one entity from another. Among these features are the location of the defect in relation to cord insertion, the size and contents of the defect, and the associated anomalies. This article reviews the underlying defects, the characteristic ultrasound findings, the associated anomalies, and the prognosis of simple and complicated abdominal wall defects. The basic features of simple abdominal wall defects (i.e., omphalocele and gastroschisis) were used as the initial points of assessment. A comparison of the different features of these abnormalities and how they differ from one another resulted in the development of criteria that facilitated the understanding of the different ultrasound manifestations of these anomalies.

Exomphalos (omphalocele)

Exomphalos affects approximately 3 in 10,000 births and can arise from a number of developmental insults. The clinical outcome is dependent upon the associated structural and chromosomal anomalies and the gestation at delivery. Accurate antenatal ultrasound diagnosis and karyotyping are important and allow informed prenatal and postnatal management decisions to be made. Prenatal care and counselling should be multidisciplinary and information should ideally be given to parents regarding prognosis and outcome based on prospectively collected population-based data.

Omphalocele in Miller-Dieker syndrome: expanding the phenotype

We report on a patient prenatally diagnosed with omphalocele, mild cerebral ventriculomegaly, nuchal fold thickening, and cystic changes in the umbilical cord who was found postnatally to have lissencephaly type I. Prenatal chromosome analysis showed a normal male karyotype; however, postnatal high resolution banding and FISH analysis, using a probe for locus D17S379 in chromosome region 17p13.3, demonstrated a deletion at 17p13.3 consistent with Miller-Dieker syndrome (MDS). A review documented four more cases with MDS/isolated lissencephaly/17p-, with omphalocele. Because MDS is a contiguous gene disorder, we speculate that a gene or genes in this region have a major role in the closure of the lateral folds or the return of the midgut from the body stalk to the abdomen at 5-11 weeks of gestation. Prenatal diagnosis of omphalocele with mild ventriculomegaly should prompt FISH analysis for a deletion in 17p13.3.

Otopalatodigital syndrome type II associated with omphalocele: report of three cases

We present 3 patients with otopalatodigital (OPD) syndrome type II and omphalocele; 2 of the cases are brothers. There are now 6 known cases of OPD type I or II with omphalocele. We propose that this combination is not coincidental and discuss mechanisms that may result in the combination of OPD, omphalocele, and other midline defects.

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

On the basis of clinical manifestations, epidemiologic characteristics, and the presence of additional malformations, omphalocele (OM) and gastroschisis (GA) are considered casually and pathogenetically distinct abdominal wall defects. More than 50% of infants with OM have additional defects, but only about 15% of those with GA do. To evaluate whether there is heterogeneity between isolated and multiply affected cases of OM and GA, we analyzed epidemiologic characteristics and familial risks of major defects for 82 OM and 81 GA cases drawn from a population-based study in the Maryland-Washington, DC-Northern Virginia area and born from 1980 through June 1987. We examined year of birth, sex, race, and maternal age distributions after stratifying the infants into isolated and multiple defect groups. We found significant differences in maternal age between cases with isolated OM and GA, but not between cases with GA or OM who had other defects. Using regressive logistic models, we analyzed familial aggregation of birth defects among relatives of infants with OM and GA. An autosomal recessive model of inheritance was found to be the most parsimonious explanation for the families of infants with isolated OM or GA. However, for families of infants with multiple defects, a sporadic or nongenetic model fit best. These findings are not only useful for estimating familial risk of major birth defects, but they also suggest further heterogeneity of infants with OM and GA according to the presence of other malformations.

Familial omphalocele: considerations in genetic counseling

Nonsyndromal omphalocele is generally regarded as a sporadic malformation. Recurrence risk is considered negligible. We report on a patient in whom 5 consecutive pregnancies (by 2 separate nonconsanguineous partners) were complicated by omphalocele as an isolated defect. Neither the patient nor her partners had history of relatives with omphalocele, although the patient's brother and his son had large umbilical hernias requiring repair in infancy. Some familial cases of nonsyndromal omphalocele have been previously reported; most such pedigrees suggest vertical transmission, although there are a few cases with only a single generation involved. In our case, the multigenerational finding of ventral wall hernias makes an autosomal dominant mechanism with variable expressivity a tenable explanation. The collected instances of familial nonsyndromal omphalocele emphasize omphalocele heterogeneity and caution in counseling recurrence risks.

Gastroschisis and omphalocele

The experience of 73 consecutive infants with gastroschisis and omphalocele is reported. The overall survival rate was 80 percent; however, since 1973 the survival rate for ruptured and intact omphaloceles has been 87 percent and 93 percent for gastroschisis. This remarkable reduction in mortality has been attributed primarily to the advent of total parenteral hyperalimentation, but mortality has also decreased due to the use of pediatric respirators which overcome the effects of increased intraabdominal pressure, and the creation of the neonatal intensive care unit where monitoring of these often fragile infants and the presence of specialty personnel assist in their care.

Etiological study of omphalocele

The epidemiological, teratological and genetic data on 134 index patients with omphalocele (79 isolated and 55 multiple ones) and on 134 matched controls born in Hungary 1970-1976 were studied medical records and by retrospective interview. The stillbirth rate and infant mortality are significantly higher, and there is intrauterine weight retardation and more frequent preterm delivery. The distribution of maternal age-groups shows a 'U-shaped' trend in isolated omphalocele. Spontaneous abortions were significantly higher, particularly in previous pregnancies of mothers of index patients. A striking higher incidence of early and late toxaemia was found in the pregnancies of mothers of the isolated omphalocele group. Sib occurrence was not found in 161 brothers and sisters. Thus amniotic fluid AFP examination is not recommended in subsequent pregnancies. The occurrence of other congenital abnormalities corresponds to 'random' risk.

Omphalocele in half-siblings

A family is described in which half-siblings, a boy and a girl born to unrelated mothers and a phenotypically normal father, were affected with omphalocele. The suggested mode of transmission remains unclear. Prenatal diagnosis to detect an affected fetus should be offered to relatives of omphalocele-affected individuals.