Maternal uniparental disomy of chromosome 16 and body stalk anomaly

We report on a fetus with placental trisomy 16, maternal uniparental disomy (UPD), and body stalk anomaly. Body stalk anomaly is a rare, fatal develop mental abnormality consisting of a defective abdominal wall with abdominal organs in a sac outside the abdominal cavity covered by amnion adherent to the placenta with absence or severe shortness of the umbilical cord. Trisom y 16 was identified in the placenta in all cells. Amniocentesis was karyoty pically normal. Parental origin studies showed maternal UPD for chromosome 16 in post-termination fetal tissue. The cause of the body stalk anomaly is not clearly defined. There are no other reports of placental karyotype or UPD investigations with body stalk anomaly. To our knowledge, this is the f irst report of placental trisomy 16, UPD in fetus, and body stalk anomaly, suggesting placental insufficiency or imprinting effects as cause of this a nomaly. Am. J. Med. Genet. 94:284-286, 2000. (C) 2000 Wiley-Liss, Inc.