Are hydatidiform moles inherited?
Most hydatidiform moles are sporadic. This means they occur once in a woman’s life. They occur at random. Sporadic disorders are not usually passed down from one generation to the next (heritable). Sometimes, a woman has recurrent hydatidiform moles. Recurrent moles occur due to a genetic change. Genetic changes, or mutations, can be passed on to future generations. The mutations in recurrent hydatidiform mole are passed on in an autosomal recessive pattern. We have two copies of every gene. We get one copy from our mom and one from our dad. In recessive disorders, both copies of the gene involved in the disorder have mutations. People with one mutated copy are called carriers. Carriers are not affected. Both parents have to be carriers of a recessive disorder to have an affected child. If both parents are carriers, they have a 25% chance to have an affected child. Women who are affected with recurrent hydatidiform mole usually cannot have a normal pregnancy. There are two genes that have been linked to this disorder. They are NLRP7 and KHDC3L. Mutations in either one of these genes can cause recurrent hydatidiform mole. Talk to a genetic counselor to find out more about the genetics of molar pregnancy. A genetic counselor can explain how disorders are passed on in families and what the risk is to other family members. To find a genetic counselor near you, visit the Find a Genetic Counselor tool on the National Society of Genetic Counselors website.