Genetic characterisation of circulating fetal cells allows non-invasive prenatal diagnosis of cystic fibrosis.
OBJECTIVE
Cystic fibrosis (CF) is an autosomal recessive disease due to mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The purpose of this study was to develop a molecular method to characterise both paternal and maternal CFTR alleles in DNA from circulating fetal cells (CFCs) isolated by ISET (isolation by size of epithelial tumour/trophoblastic cells).


METHODS
The molecular protocol was defined by developing the F508del mutation analysis and addressing it both to single trophoblastic cells, isolated by ISET and identified by short tandem repeats (STR) genotyping, and to pooled trophoblastic genomes, thus avoiding the risk of allele drop out (ADO). This protocol was validated in 100 leucocytes from F508del carriers and subsequently blindly applied to the blood (5 mL) of 12 pregnant women, at 11 to 13 weeks of gestation, whose offspring had a 1/4 risk of CF. Ten couples were carriers of F508del mutation, while two were carriers of unknown CFTR mutations.


RESULTS
Results showed that one fetus was affected, seven were heterozygous carriers of a CFTR mutation, and four were healthy homozygotes. These findings were consistent with those obtained by chorionic villus sampling (CVS).


CONCLUSIONS
Our data show that the ISET-CF approach affords reliable prenatal diagnosis (PND) of cystic fibrosis and is potentially applicable to pregnant women at risk of having an affected child, thus avoiding the risk of iatrogenic miscarriage.
Saker
Ali
A
INSERM, Unité 807, Paris, France, Université Réné Descartes, Paris, France.
Benachi
Alexandra
A
Bonnefont
Jean Paul
JP
Munnich
Arnold
A
Dumez
Yves
Y
Lacour
Bernard
B
Paterlini-Brechot
Patrizia
P
D000483:Alleles; D003550:Cystic Fibrosis / Q000175:diagnosis* / Q000235:genetics; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics*; D005260:Female; D005333:Fetus / Q000166:cytology*; D005820:Genetic Testing / Q000379:methods*; D006801:Humans; D009154:Mutation; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*
D019005:Cystic Fibrosis Transmembrane Conductance Regulator