Diagnosis of complete molar pregnancy by microsatellites in archival material.

AIMS To develop an assay which would determine the parentage of hydatidiform molar pregnancies. METHODS DNA was extracted from formalin fixed, paraffin wax embedded tissue from hydatidiform molar pregnancies and spontaneous abortions after separation of chorionic villi and decidua. PCR amplification of dinucleotide repeat sequences ("microsatellites") was performed using three different primers. Products were radioactively labelled and visualised by autoradiography of dried polyacrylamide gels. RESULTS With informative microsatellites, diagnostic patterns of amplification were obtained. Complete moles yielded either one or two microsatellites which differed from both maternal (decidual) microsatellites. Complete mole could be excluded by all the microsatellites showing alleles identical with those in maternal DNA. CONCLUSIONS This technique offers a method of determining the presence of entirely paternal alleles in a molar pregnancy and thus confirming a complete hydatidiform mole.