Circulating trophoblastic cells provide genetic diagnosis in 63 fetuses at risk for cystic fibrosis or spinal muscular atrophy

This study sought to determine whether a reliable non-invasive prenatal diagnosis (NI-PND) of cystic fibrosis (CF) or spinal muscular atrophy (SMA) can be achieved through analysis of circulating fetal trophoblastic cells (CFTC). The kinetics of CFTC circu- lation were also studied. CFTC were isolated by isolation by size of epithelial tumour/trophoblastic cells at 9-11 weeks of gestation, before chorionic villus sampling (CVS), from the blood of 63 pregnant women at 25% risk for having a child affected by either CF (n = 32) or SMA (n = 31). Collected cells were laser-microdissected, short tandem repeat-genotyped to determine fetal origin and blindly assessed for mutation analysis. CFTC were independently analysed weekly (4-12 weeks of gestation) in 14 women who achieved pregnancy following IVF. Diagnostic results were compared with those obtained by CVS. All seven CF and seven SMA preg- nancies carrying an affected fetus were correctly identified as well as non-affected pregnancies. CFTC provided 100% diagnostic sensitivity (95% CI 76.8-100%) and specificity (95% CI 92.7-100%) in these 63 consecutive pregnancies at risk for CF or SMA. CFTC were found to circulate from 5 weeks of gestation and can be used to develop an early and reliable approach for NI-PND. RBMOnline