Causes of Multiple Endocrine Neoplasia

Multiple Endocrine Neoplasia Type 1

MEN1 is caused by an alteration in the gene MEN1, which carries the code for a protein called menin. Menin functions as a tumor suppressor; it helps keep cells growing normally in a controlled fashion. If alterations occur in the gene that carries the code for menin, it can’t control the formation of tumors.

MEN1 is an inherited condition, which means it can be passed from an affected parent to a child.

MEN1 is inherited in this manner:

  • MEN1 follows an autosomal dominant inheritance pattern, which means you need to receive the gene from only one parent to develop the disease.
  • We have two copies of every gene — one copy from our mother and one copy from our father.
  • An individual with MEN1 has one working copy of the MEN1 gene and one altered copy that is not working.
  • Each time we have a child, we pass on half of our genetic information, or one of the two copies of every gene.
  • If someone has MEN1, his or her child has a 50 percent chance of receiving the altered copy of the MEN1 gene and having MEN1 as well. This means they also have a 50 percent chance of receiving the working copy of the MEN1 gene.

Approximately 10 percent of people with MEN1 have a de novo (new) alteration of the MEN1 gene with no family history of the MEN1 condition.

Multiple Endocrine Neoplasia Type 2

MEN2 is caused by an alteration in the RET gene. This alteration causes an increased risk for developing medullary thyroid cancer and the various tumors associated with MEN2.

MEN2 is an inherited condition, which means it can be passed from an affected parent to a child.

MEN2 is inherited in this manner:

  • MEN2 follows an autosomal dominant inheritance pattern, which means you need to receive the gene from only one parent to develop the disease.
  • We have two copies of every gene — one copy from our mother and one copy from our father.
  • An individual with MEN2 has one working copy of the RET gene and one altered copy that is not working.
  • Each time we have a child, we pass on half of our genetic information, or one of the two copies of every gene.
  • If someone has MEN2, his or her child has a 50 percent chance of receiving the altered copy of the RET gene and having MEN2 as well. This means they also have a 50 percent chance of receiving the working copy of the RET gene.
  • If a person inherits the RET gene, he or she has an almost 100 percent chance of developing medullary thyroid cancer and the other symptoms associated with MEN2.

In some cases, persons with MEN2 have a de novo (new) alteration of the RET gene with no family history of the MEN2 condition.

If you are concerned that you or a member of your family may have a hereditary condition that may affect your chances of developing MEN1 or MEN2, ask your physician for a referral to the Scott & White Genetics Clinic for genetic counseling and possible testing to determine whether you have a predisposition to either of these diseases.

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