AMHR2

The AMHR2 gene provides instructions for making the anti-Müllerian hormone (AMH) receptor type II, which is involved in male sex differentiation. The AMH receptor type II is found on the surface of Müllerian duct cells. The Müllerian duct, found in both male and female fetuses, is the precursor to the female reproductive organs. During development of male fetuses, cells of the testes release a protein called the AMH protein. The AMH protein attaches (binds) to the AMH receptor type II, which signals self-destruction (apoptosis) of the Müllerian duct cells. As a result, the Müllerian duct breaks down (regresses) in males. In females, who do not produce the AMH protein during fetal development, the Müllerian duct becomes the uterus and fallopian tubes.

persistent Müllerian duct syndrome - caused by mutations in the AMHR2 gene

Persistent Müllerian duct syndrome type 2, a disorder of sexual development that affects males, is caused by mutations in the AMHR2 gene. Males with this condition have female reproductive organs in addition to normal male reproductive organs. At least 24 mutations in the AMHR2 gene have been identified in people with persistent Müllerian duct syndrome type 2. Most mutations change single protein building blocks (amino acids) in the AMH protein. Other mutations result in a premature stop signal that leads to an abnormally short protein. Still other mutations delete regions of DNA from the AMH gene, which changes the instructions for the protein. The most common mutation, a deletion of 27 DNA building blocks (nucleotides), occurs in about half of affected individuals with an AMHR2 gene mutation.

Mutations in the AMHR2 gene lead to an abnormal protein that is stuck inside the Müllerian duct cells and not found on the surface. Therefore, the cells cannot receive the signal for apoptosis. As a result, the Müllerian duct persists and becomes a uterus and fallopian tubes. Because the AMH receptor type II is not involved in the formation of male reproductive organs, affected males also have male reproductive organs.