[Genetic heterogeneity for familial recurrent hydatidiform mole]

To determine the parental origin of the genome in the molar pregnancies of two familes with familial recurrent hydatidiform mole (FRHM) and to investigate whether the gene responsible for FRHM is likely to be located within the 19q13.4 region in these familes.

The features of complete hydatidiform mole (CHM) were confirmed by pathological examination. DNA of CHM was prepared from sections of formalin-fixed paraffin-embedded blocks of molar tissue following laser capture microdissection. The polymerace chain reaction was used to amplify microsatellite polymorphisms in DNA from the patients, their husbands and the captured molar tissue. Parental contributions to the molar tissue were determined using ABI 310 GeneScan software. Genotyping and haplotype analysis of the candidate region on 19q13.4 was performed for members of both families using 25 microsatellite markers.

One CHM from each family was identified as a biparental complete hydatidiform mole. All patients were heterozygous for most of the markers in the chromosome region of interest. In addition the two affected sisters in one of the families had different genotypes for the 19q13.4 region, suggesting that mutations in a different locus might be responsible for the disorder in this family.

The location of the gene responsible for FRHM is unlikely to be located in the 19q13.4 chromosomal region in these two families suggesting that FRHM shows genetic heterogeneity.