Our laboratory continues to be actively involved in the development of new
biomarkers for prenatal diagnosis using maternal blood and amniotic fluid. We have also developed a mouse model that demonstrates that cell-free fetal (cff)
DNA is detectable in the pregnant maternal mouse. In human maternal plasma and serum we have analyzed factors that are important in the clinical interpretation of cff
DNA levels. Maternal race, parity, and type of conception (natural or assisted) do not affect cff
DNA levels, but maternal weight does. We have also analyzed the relationship between placental volume, using a three-dimensionsal ultrasound examination, and cff
DNA levels. Surprisingly, there is no association between these values. Finally, we are using specific disease models (such as
congenital diaphragmatic hernia and
twin-to-twin transfusion) to understand the effects of gestational age and specific pathology on fetal gene expression by analyzing cell-free
mRNA levels in maternal plasma. In the amniotic fluid we have focused on improvements in recovery of cff
DNA and
mRNA. By optimizing recovery we have made some interesting observations about differences in fetal
DNA between blood and amniotic fluid. In addition, we have successfully hybridized cff
DNA in amniotic fluid to
DNA microarrays, permitting assessment of fetal molecular karyotype. We also have preliminary data on fetal gene expression in amniotic fluid. Finally, we remain actively involved in promoting noninvasive prenatal testing in the United States, such as encouraging the use of fetal
DNA for fetal rhesus D assessment. On the other hand, we are cautious and concerned about the accuracy of "at-home" kits for fetal gender detection.