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The prevalence of POC is estimated to be 1/65,000-1/200,000 live births.

POC is a congenital disorder characterized by the presence of 5 major malformations: midline supraumbilical abdominal wall defect (diastasis recti, epigastric and umbilical hernia), lower sternal defect (sternal cleft (see this term), absent xiphoid process, short sternum and defective formation of lower two third), diaphragmatic pericardial defect, anterior diaphragmatic defect and heart malformations (ventricular septal defect (72%), interauricular communication (35%), cardiac diverticulum (32%), congenital pulmonary valve stenosis (PS; 31%) (isolated PS or in combination with double outlet right ventricle in fetuses with EC and univentricular heart in fetuses without EC), tetralogy of Fallot (17%), dextrocardia (15%), and transposition of the great arteries (TGA; 6%) (see these terms)). Thoraco-abdominal wall defects may lead to omphalocele (see this term) and EC, with the heart located outside the thoracic wall and sometimes covered by pigmented loose skin. The heart can be partially or completely repositioned into the thoracic cavity when the patient is in a supine position. Neonates usually present with severe respiratory distress and cyanosis. Additional features that may be observed include craniofacial and central nervous system (CNS) anomalies (cleft lip and/or palate, encephalocele, craniorachischisis (see these terms) and hydrocephalus), limb defects (club foot, absence of tibia/radius, hand and foot oligodactyly, phocomelia (see this term), and abdominal organ defects (gallbladder agenesis and polysplenia, as part of heterotaxia (see this term)). POC may occur in association with Trisomy 13, 18, Down syndrome and Turner syndrome (see these terms).

The etiology of POC is still unknown. It has been postulated that at around 14 to 18 days post conception, a failure of the lateral mesodermal folds to migrate to the midline may cause the sternal and abdominal wall defects and abnormal development of the septum transversum result in defects in the anterior diaphragm and pericardium.

Diagnosis of complete POC relies on the following classification: class 1, a definite diagnosis, when all 5 defects are present; class 2, a probable diagnosis with 4 defects being present, including intracardiac and ventral wall abnormalities; and class 3, an incomplete expression with various combinations of defects being present, including a sternal abnormality.

Differential diagnosis includes limb body wall complex, omphalocele (see these terms), thoracic EC and amniotic bands (see this term).

Prenatal diagnosis can be made in first-trimester ultrasonography by detection of multiple thoraco-abdominal defects, including EC and CNS anomalies.

POC usually occurs sporadically but rare cases of chromosomal anomalies, autosomal or X-linked transmission have also been reported.

Management is surgical, consisting of palliative repair of the ventral hernia and diaphragmatic defect and palliative or corrective repair of the cardiovascular anomalies. Surgical repair to relocate the heart into the chest cavity is usually performed in the neonatal period or in infancy. For patients unable to tolerate a single-staged approach, an intraoperative ''heart restoring'' trial may be proposed. If heart position can be successfully restored without obvious hemodynamic changes, one-staged operation is advised; if hemodynamic changes are minor, a combined operation may be possible.

The prognosis of POC is poor and only few patients survive through early childhood. The main causes of death are tachyarrhythmias, bradycardia, low blood pressure, rupture of the diverticulum, and heart failure.