Study of the Genetic and Epigenetic Causes of Recurrent Hydatidiform Moles

The researchers' laboratory is studying a rare class of highly recurrent hydatidiform moles. These are usually complete hydatidiform moles (CHM), but sometimes they are partial hydatidiform moles PHM). With sporadic moles, the difference between CHMs and PHMs is that with CHMS, there is not typically an embryo or fetus at the time of diagnosis but with a PHM there may be a fetus. Also, CHMs have 46 chromosomes in each cell. While this is the number of chromosomes that should be found, the problem is that all the chromosomes come from the father. Normally, half the chromosomes should come from the mother and half should come from the father. Unlike CHMs, PHMs have 69 chromosomes. This means that PHMs have three copies of each chromosome when they should only have two. The extra copy comes from the father.

The researchers' study focuses on moles that are genetically different from these sporadic moles in that they have 23 chromosomes from the mother and 23 chromosomes from the father - just like a normally developing pregnancy. These are called biparental moles because the mutation that causes the mole comes from both parents. This mutation occurs in a gene called NLRP7. The researchers' team is working to understand how mutations in NLRP7 leads to CHMs and how these mutations may lead to other types of pregnancy loss. The researchers are also trying to discover other genetic and epigenetic factors that may lead to moles.