Chorionic villus sampling (CVS) and fluorescence in situ hybridization (FISH) for a rapid first-trimester prenatal diagnosis.
OBJECTIVE
Early diagnosis of unbalanced chromosomal abnormalities can be crucial in minimizing the trauma caused by an elective abortion. Chorionic villus sampling (CVS) can be performed from 9 weeks of gestation. However, two major problems are encountered in fetal karyotyping using cultured cells from chorionic villi: the relatively slow growth of these cells in culture, which delays the diagnosis, and the occurrence of maternal cell contamination (MCC). With FISH, a result can be obtained within 24 h, and, as no cell culturing is involved, the problem of MCC is minimized.


METHODS
Thirty-two women undergoing CVS between 9 and 12 weeks of gestation were offered FISH analysis in addition to the standard chromosome analysis.


RESULTS
FISH was informative in all of the cases tested. Eleven aneuploidies were detected in cases of hygroma or abnormal nuchal translucency and two out of four fetuses from parental translocation were unbalanced. The decision to perform early termination of these chromosomally abnormal pregnancies was based on FISH results and ultrasound abnormalities, without waiting for karyotype results.


CONCLUSIONS
The present study confirms that the association of FISH and CVS allows a rapid and early prenatal diagnosis, and emphasizes that this association is of great benefit in cases of known parental balanced translocation or when hygroma is detected by ultrasonography.
Goumy
Carole
C
Cytogénétique Médicale, Faculté de Médecine/CHU, Clermont-Ferrand, France. carole.goumy@u-clermont1.fr
Bonnet-Dupeyron
Marie-Noëlle
MN
Cherasse
Yoan
Y
Laurichesse
Hélène
H
Jaffray
Jean-Yves
JY
Lacroute
Gisèle
G
Geneix
Aimé
A
Lemery
Didier
D
Vago
Philippe
P
D000782:Aneuploidy; D015193:Chorionic Villi Sampling; D002869:Chromosome Aberrations; D005260:Female; D005865:Gestational Age; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D018191:Lymphangioma, Cystic / Q000235:genetics; D009333:Neck / Q000000981:diagnostic imaging / Q000196:embryology; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011296:Prenatal Diagnosis / Q000379:methods*; D014178:Translocation, Genetic; D016216:Ultrasonography, Prenatal