Analysis of molar DNA in maternal serum in a case of hydatidiform mole

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Complete hydatidiform mole lacks a fetal component, and DNA originating from a hydatidiform mole (molar DNA) that is detected in the maternal circulation is thought to originate from villous tissue. By analyzing by real-time PCR the amount of sex-determining region Y (SRY) DNA in maternal serum before and after delivery of a 46,XY complete hydatidiform mole coexisting with a normal 46,XX fetus, we have confirmed that the DNA in maternal blood originates from villous tissue. The patient was a 30-year-old gravida I, para 0. She was examined at our hospital at 20 weeks of gestation. Ultrasound examination showed a normally grown fetus without anomalies with a normal placenta, and a molar placenta. At 28 weeks of gestation, she spontaneously delivered vaginally a 1094-g female infant with a grossly normal placenta, and a molar placenta. Serum β-hCG was 367 747.8 IU/L at 20 weeks and gradually decreased as a function of gestational age. The β-hCG concentration was 147 644.2 I U/L at 1 week … More before delivery and rapidly decreased to 6512.4 IU/L by 1 week after delivery. The β-hCG concentration had decreased to within reference values by 13 weeks after delivery. No increase in β-hCG was observed thereafter. The highest number of SRY copies in maternal serum was observed at 20 weeks of gestation, and the number of copies decreased toward delivery. The concentration of SRY sequence was 124.43 copies/mL at 1 week before delivery and rapidly decreased to 8.24 copies/mL at 1 week post delivery. The number of SRY copies decreased further, and no SRY was detectable at 5 weeks after delivery. In the present study, we have shown that the SRY sequence derived from a complete hydatidiform mole exists in maternal serum. Because our case here is a 46,XY heterozygous complete hydatidiform mole coexisting with a normal 46,XX fetus, the SRY sequence in maternal circulation originated entirely from molar placental tissue. However, in our study, before delivery, the concentration of molar DNA showed a pattern similar to that of hCG, which is widely used clinically as a marker of molar diseases. It would be interesting to study whether the SRY sequence is also detectable with the recurrence of molar disease. If so, molar DNA in maternal blood could also be used as a marker for monitoring of molar diseases. Less