Acardia is a bizarre fetal malformation occurring only in twins or triplets. It is also called acardius acephalus, acardiac twinning, or twin reversed arterial perfusion (TRAP) syndrome or sequence. This condition is very rare and occurs in 1 in 34,600 births or 1 in 100 monozygotic twins (Gillim and Hendricks 1953) and 1 in 30 monozygotic triplets (Van Allen et al. 1983; Napolitani and Schreiber 1960; Moore et al. 1990; Sanjaghsaz et al. 1998; Blenc et al. 1999) and even in quintuplets. Almost all cases reported are monozygotic twins. However, there are reports of dichorionic monozygotic twin gestations with TRAP sequence (French et al. 1998; Gewolb et al. 1983).
KeywordsUmbilical Cord Monozygotic Twin Umbilical Artery Esophageal Atresia Imperforated Anus
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