NONINVASIVE EARLY PRENATAL MOLECULAR DIAGNOSIS USING RETRIEVED TRANSCERVICAL TROPHOBLAST CELLS

Fetal DNA was recovered from 17 of 39 (41%) transcervical cell (TCC) s amples obtained between 7 and 9 weeks of gestation by endocervical can al flushing, Trophoblast retrieval was adequate for polymerase chain r eaction (PCR) amplification of Y chromosome-specific DNA sequences and detection of paternal-specific microsatellite alleles. The fetal sex predicted by PCR in TCCs was confirmed in all cases by karyotype analy sis of chorionic villi at 10 weeks of gestation. The absence of the di sease-associated paternal alleles in TCC samples from two pregnancies at risk for spinal muscular atrophy and myotonic dystrophy predicted u naffected fetuses in agreement with subsequent results on chorionic vi lli and newborns' leukocytes. A trisomy 21 fetus was diagnosed in TCCs using fluorescent in situ hybridization (FISH) and semiquantitative P CR analysis of superoxide dismutase-1 (SOD 1). Present experience indi cates that TCC sampling is a promising technique for early prenatal mo nitoring of Mendelian disorders and chromosome aneuploidy.