Aspectos genéticos de la mola hidatidiforme

Abstract

The hydatidiform mole (HM) consists in an abnormal pregnancy, featured by hydropic degeneration of the chorionic villi and trophoblastic hyperplasia. It is classified as complete hydatidiform mole (CHM) and partial hydatidiform mole (PHM) and has an incidence in Europe and North America of 1-3:1,000 pregnancies, in Mexico the incidence has been estimated in 2.4:1,000 pregnancies. From 10 to 30% of the HM complicate with persistent trophoblastic gestational disease. Almost 75% are classified as CHM, which have a diploid androgenetic chromosome complement; histopathological features are diffuse hydropic edema, and trophoblastic hyperplasia of the syncytiotrophoblast, cytotrophoblast and intermediate trophoblast. The remaining 25% are classified as PHM, with a triploid chromosome complement; histopathological features are the presence of two villi populations, and syncytiotrophoblast and cytotrophoblast hyperplasia. Most of the HMs are sporadic, with general recurrence in 0.6 to 2.57% of total cases. The occurrence of two or more molar pregnancies in the same patient is known as recurrent mole, in this case there are two groups: those with RM of androgenetic origin and those with a diploid complement and biparental origin (DCBP). In the first case it's rare to have a third molar pregnancy and reproductive outcome is better, in those patients with DCBP, their etiology has been related with maternal metilation alterations in molar tissue, the majority of patients with this type of molar pregnancy have mutations in NLRP7 and KHCD3L genes, the reproductive outcome is adverse, with a probability of a normal term pregnancy of 5-7%.