Case Report: Prenatal Testing for CMV Infection. A year later, the same couple returned to our Center for genetic counseling because the attending obstetrician had advised them that the fetus being carried in a second preg­nancy was probably infected by CMV. Already in the 19th week of pregnancy, the woman had been tested for serum anti-CMV antibodies at regular intervals and had been repeatedly found to be IgG positive and IgM negative. Nevertheless, she was advised by the caring obstetrician to have a molecular prenatal test following amniocentesis. Although not necessary, amniocentesis was performed at 18.5 weeks of pregnancy, and the PCR test indicated the presence of CMV DNA. The obstetrician advised termina­tion of the pregnancy, and the distressed couple came to us in order to obtain a second opinion and for genetic coun­seling.

During a counseling session, in addition to psychologi­cal support, we discussed with the couple that the obtained data by others (IgG +, IgM -, and positive PCR prenatal testing) could raise two distinct possibilities: a) either there was an acute recurrence of CMV infection, thus although IgM were still negative a couple of weeks ago the embryo was at great risk of being infected; b) or there was no recurrence of CMV infection, and the PCR results were false positive due to a possible contamination of the amniotic fluid sample by maternal leukocytes, because of a rupture of a blood vessel during amniocentesis.

In order to distinguish between these two different options, and to better determine the risk to the fetus, the pregnant woman was advised to have a repeat test of serum IgG, IgM antibodies, and PCR detection of CMV DNA in her total blood and serum.

Methods. The anti-CMV IgG and IgM were qualita­tively and quantitatively tested by standard ELISA meth­odology [13]. Total DNA was isolated by blood and serum of the woman using Nucleospin® Blood QuickPure Kit (Macherey-Nagel, Duren, Germany). Amplification of a 435 bp region of the Major Immediate Early gene of CMV was effected in a standard Taq DNA polymerase reaction of 50 mL, by using 5 mL DNA, primers MIE-4B (5’-CCA AGC GGC CTC TGA TAA CCA AGC C-3’), MIE-5 (5’-CAG CAC CAT CCT CCT CTT CCT CTG G-3’), and PCR conditions as follows: initial denaturation at 94°C for 5 min, 40 cycles at 94°C for 1 min, 55°C for 2 min, 72°C for 3 min, and a final elongation step at 72°C for 7 min. In addition to the woman’s samples, the same PCR reaction was performed on a DNA sample from a CMV carrier (positive control) and a DNA sample of a non carrier (neg­ative control). The PCR products were electrophoresed in a 1% agarose gel in parallel with a molecular weight marker. The same molecular procedure was performed in two independent sets of reactions.