Biamnial alpha fetoprotein concentration in twins, one with multiple malformations.

In the 18th week of pregnancy in a 22 year old patient, twins were diagnosed by ultrasound. It was found that one twin had an abnormal skull outline and an echo-free area covered by a thin membrane in the region of the abdomen. The second embryo showed no sign of malformation. Amniocentesis was performed and the AFP in both samples of amniotic fluid were in the pathological range. Our own observations with indirect immunofluorescence confirmed that one twin with defects leading to abnormally high AFP levels can cause pathological AFP levels in the amniotic sac of a healthy twin.