The Genetics of Familial Hydatidiform Moles: the Identification of the First Maternal Effect Gene in Humans

Hydatidiform Moles are an abnormal pregnancy in which no foetus forms. Instead, the placental villi proliferate as fluid filled sacs with tumourigenic potential. This is a relatively common disorder occurring in 1 in 1500 pregnancies in North America, and even higher in other populations. In certain women hydatidiform moles have been found to recur, and in even rarer cases they recur in multiple women in the same family. These recurrent cases have allowed identification of a genetic defect causing these moles. Mutations in NLPR7, a gene implicated in the innate immune response, were originally identified in four families with recurrent moles, pinpointing it as the gene responsible for this disorder. This work introduces the history of molar research, describes the identification of the causative gene and gives insights into possible mechanisms for the manifestation of this disorder.