Background: Trisomy 13 (Patau Syndrome) occurs in approximately 1 in 5.000 live births. It is rarely compatible with life, and prolonged survival is scarce. Anomalies often involve the urogenital, cardiac, craniofacial, and central nervous systems. Cardiovascular malformations are invariably present,
the leading malformation being an infundibular ventricular septal defect often in combination
with dextroposition of the aorta and abnormalities of the semilunar valves.
Case Report: We report a male newborn infant with wide saggital suture and anterior fontanel (3X4 cm); short neck; low-set hairline and auricles; bilateral microphthalmos; cleft palate; 11 localized scalp lesions in the parietal region; bilateral polydactyly; hyperconvex, narrow fingernails; bilateral transverse crease on the palm; posterior prominence of the heel; hypoplastic toenails; equinovarus deformity; fibular S-shaped hallucal dermal ridge pattern; single umbilical artery and cavernous hemangiomata; left inguinal hernia; abnormal scrotum and bilateral cryptorchidism. On
his autopsy he had univentricular atrioventricular (AV) connexion. He diagnosed as trisomy 13 on clinical grounds and chromosomal analysis. We lost him at the end of the second day because of severe apnea-bradycardia.
Conclusions: To our knowledge, univentricular AV connexion associated with trisomy 13 has not been previously described.

Keywords: trisomy 13, cardiac defects, univentricular atrioventricular connexion