Omphalocele

An omphalocele (British English: omphalocoele) is a type of abdominal wall defect in which the intestines, liver, and occasionally other organs remain outside of the abdomen in a sac because of a defect in the development of the muscles of the abdominal wall (exomphalos). Omphalocele occurs in 2.5/10,000 births and is associated with a high rate of mortality (25%) and severe malformations, such as cardiac anomalies (50%) and neural tube defect (40%). Approximately 15% of live-born infants with omphalocele have chromosomal abnormalities.

Presentation

The sac, which is formed from an outpouching of peritoneum, protrudes in the midline, through the umbilicus (navel).

It is normal for the intestines to protrude from the abdomen, into the umbilical cord, until about the tenth week of pregnancy, after which they return to inside the fetal abdomen.

The omphalocele can be mild, with only a small loop of intestines present outside the abdomen, or severe, containing most of the abdominal organs. In severe cases surgical treatment is made more difficult because the infant's abdomen is abnormally small, having had no need to expand to accommodate the developing organs.

The presence of an omphalocele is often associated with cardiac defects.^{[citation needed]}

Screening

An omphalocele is often detected through AFP screening or a detailed fetal ultrasound. Genetic counseling and genetic testing such as amniocentesis is usually offered during the pregnancy.

Causes

Some cases of omphalocele are believed to be due to an underlying genetic disorder, such as Edward's syndrome (Trisomy 18)^[1][2] or Patau Syndrome (Trisomy 13).

Related conditions

Gastroschisis is a similar birth defect, but in gastroschisis the umbilical cord is not involved and the lesion is usually to the right of midline. Parts of organs may be free in the amniotic fluid, and not enclosed in a membranous (peritoneal) sac. This condition is less commonly associated with other defects than omphalocele.

Other related syndromes are Pentalogy of Cantrell, Beckwith-Wiedemann, and OEIS Complex.

References

1. ^ Kanagawa SL, Begleiter ML, Ostlie DJ, Holcomb G, Drake W, Butler MG (2002). "Omphalocele in three generations with autosomal dominant transmission". J. Med. Genet. 39 (3): 184–5. doi:10.1136/jmg.39.3.184. PMC 1735073. PMID 11897819. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1735073. 
2. ^ Yatsenko SA, Mendoza-Londono R, Belmont JW, Shaffer LG (2003). "Omphalocele in trisomy 3q: further delineation of phenotype". Clin. Genet. 64 (5): 404–13. doi:10.1034/j.1399-0004.2003.00159.x. PMID 14616763. 

External links

• The Brown Fetal Treatment Program - Providence, Rhode Island at Brown University
• Fetal Treatment Center: Omphalocele at UCSF

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