Prenatal diagnosis in type IIA von Willebrand disease.

A prenatal diagnosis for fetal disease was performed at 20 weeks gestation in a severely affected patient with type IIA von Willebrand disease. In the fetal cord blood sample obtained under ultrasound guidance, the level of von Willebrand ristocetin cofactor activity was similar to that of von Willebrand factor antigen, and all the multimers were present. These results were compared to those obtained in 51 normal fetuses of similar gestational age (19-21 weeks).

Prenatal diagnosis with biotinylated chromosome specific probes.

We have used a Y-chromosome specific DNA probe in a controlled study to determine the presence of Y-chromosome material and to detect numerical abnormalities in uncultured amniotic fluid cells by fluorescent hybridization. Using this non-radioactive method, we correctly predicted fetal sex within 48 h in all but 3 of 54 cases and identified an XYY syndrome. The technique was previously tested with no false-positive or false-negative results on cultured interphase or metaphase nuclei of fetal fibroblasts and adult T-lymphocytes.

Prenatal diagnosis of hemophilia by fetal blood sampling under ultrasound guidance.

In utero fetal blood sampling was performed in 55 cases for prenatal diagnosis of hemophilia A and B. Fifteen fetuses were found to be affected. However, with this new procedure, it was possible to demonstrate that fetuses were not hemophiliacs in 40 cases.

Vitamin K dependent proteins in fetal hemostasis at mid trimester of pregnancy.

The vitamin K dependent coagulation factor activities were measured in 63 normal human fetuses from 19 to 28 weeks of pregnancy. These activities were included between 9 to 28 percent of normal adult levels. Prothrombin antigen, factor IX antigen and protein C were also measured.