First-trimester fetal sex determination in maternal serum using real-time PCR.
Fetal sex prediction can be achieved using PCR targeted at the SRY gene by analysing cell-free fetal DNA in maternal serum. Unfortunately, the results reported to date show a lack of sensitivity, especially during the first trimester of pregnancy. Therefore, determination of fetal sex by maternal serum analysis could not replace karyotype analysis following chorionic villus sampling. A new highly sensitive real-time PCR was developed to detect an SRY gene sequence in maternal serum. Analysis was performed on 121 pregnant women during the first trimester of pregnancy (mean gestational age: 11.8 weeks). Among them, 51 had at least one previous male-bearing pregnancy. Results were compared with fetal sex. SRY PCR analysis of maternal serum was in complete concordance with fetal sex. Among the 121 pregnant women, 61 were bearing a male fetus and 60 a female fetus. No false-negative results were observed. Furthermore, no false-positive results occurred, even though 27 women carrying a female fetus during the current pregnancy had at least one previous male-bearing pregnancy. This study demonstrates that a reliable, non-invasive sex determination can be achieved by PCR analysis of maternal serum during the first trimester of pregnancy. This non-invasive approach for fetal sex prediction should have great implications in the management of pregnant women who are carriers of an X-linked genetic disorder. Prenatal diagnosis might thus be performed for male fetuses only, avoiding invasive procedures and the risk of the loss of female fetuses.
Costa
J M
JM
Centre de Diagnostic Prénatal, American Hospital of Paris, Neuilly-sur-Seine, France. jean-marc.costa@ahparis.org
Benachi
A
A
Gautier
E
E
Jouannic
J M
JM
Ernault
P
P
Dumez
Y
Y
D004247:DNA / Q000097:blood*; D004268:DNA-Binding Proteins / Q000235:genetics; D005260:Female; D006801:Humans; D008297:Male; D009687:Nuclear Proteins; D016133:Polymerase Chain Reaction / Q000379:methods*; D011247:Pregnancy; D012680:Sensitivity and Specificity; D012732:Sex Determination Analysis / Q000379:methods*; D051876:Sex-Determining Region Y Protein; D014157:Transcription Factors
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C497745:SRY protein, human; D051876:Sex-Determining Region Y Protein; D014157:Transcription Factors; D004247:DNA