PRENATAL-DIAGNOSIS ON FETAL CELLS FROM BLOOD OF PREGNANT-WOMEN - EXPERIENCES FROM BASEL

Currently prenatal diagnosis relies on invasive procedures such as cho rion villus sampling (CVS) or amniocentesis (AC). Many parents are rel uctant to expose themselves and their child to the small, but signific ant risk posed by these procedures to mother and child. There is, henc e, a great need for a risk-free non-invasive alternative. To achieve t his goal most research has been focussed on enriching fetal cells from the blood of pregnant women. The erythroblast has emerged as the targ et cell of choice, since it is abundant in the early fetus, rare in no rmal adult blood, and since it has a very short half life, there is no risk of obtaining cells from previous pregnancies. Most enrichment pr otocols rely either on magnetic - or fluorescent activated cell sortin g (MACS and FAGS) using fetal specific antibodies. These enriched cell s can be examined by FISH (fluorescence in-situ hybridisation) for the presence of the most common fetal chromosomal aneuploidies (13, 18, 2 1, X and Y) or by polymerase chain reaction (PCR) on singly manipulate d cells for genetic disorders. The efficacy in detecting fetal aneuplo idies is currently being evaluated in a phase II clinical trial under the auspices of the NIH-NICHD, the so-called NIFTY Trial, in which our group is a participant. By modifying our enrichment protocols we have recently been able to obtain detection sensitivities of almost 80%, t hereby renewing our optimism that this methodology provides a solid ba sis for an effective non-invasive prenatal diagnostic test.