Genome-wide single nucleotide polymorphism array analysis unveils the origin of heterozygous androgenetic complete moles

Heterozygous CHMs have been believed as synonymous with dispermic moles (two sperm origin). The possibility of diploid sperm origin has not been considered. We assessed whether heterozygous CHMs would be of dispermic or diploid sperm origin. In all the cases, centromeric zygosity was random, i.e., mixed status. Theoretically, if the heterozygous CHMs were of diploid sperm origin, the centromeric status will be all homozygous or all heterozygous. Thus, all the analyzed heterozygous CHMs were considered to be of dispermic origin. Three cases showed the trisomy while we did not notice them with STR analysis. Diploid sperm fertilization can be rare during the development of heterozygous androgenetic CHM. The villous genomic DNA of the thirteen heterozygous CHMs was further analyzed using the single nucleotide polymorphism array. B allele frequency (BAF) plotting was used to determine the centromeric zygosity status of all chromosomes to discriminate dispermic origin from diploid sperm origin.