MEN 2A and MEN 2B Syndrome

MEN 2 Syndrome: MEN 2 stands for Multiple Endocrine Neoplasia type 2. It is a very uncommon genetic disease. Patients with the gene for MEN 2 will develop enlargement and overactivity of certain glands in the endocrine system. The endocrine system has several glands, such as the pituitary, thyroid, and adrenal glands, with each gland responsible for producing and secreting specific types of hormones that regulate the body. 

The endocrine glands that are most often affected by MEN 2 are the parathyroid, adrenal, and thyroid glands. Most patients with MEN 2 will develop medullary thyroid cancer. 

There are three subtypes of MEN 2: Familial Medullary Thyroid Cancer (FMTC), MEN 2A, and MEN 2B.

Familial Medullary Thyroid Cancer (FMTC): 
In this form of MEN 2, patients present with only medullary thyroid carcinoma. 

MEN 2A: Patients with this form of MEN 2 may have:
  • Medullary thyroid cancer
  • Pheochromocytoma (generally benign tumor in the adrenal glands)
  • Parathyroid adenoma (generally benign tumor of the parathyroid) 
MEN 2B: Patients with this form of MEN 2 may have:
  • Medullary thyroid cancer 
  • Pheochromocytoma (generally benign tumor in the adrenal glands)
  • Mucosal neuroma (benign tumor of nerve tissue on the tongue and lips) 
  • Digestive problems
  • Muscle, joint, and spinal problems 
  • Certain facial features typical of MEN 2B, including swollen lips and thick eyelids

Causes of MEN 2A and MEN 2B Syndrome

MEN2 is a genetic condition, which means it is passed on from generation to generation within a family. The specific gene associated with MEN2 is called RET. There is a mutation in the RET gene of patients with MEN2, and this mutation increases the risk for getting medullary thyroid cancer, as well as other symptoms of MEN2. 

MEN2 is an autosomal dominant inheritance, which means that only one parent needs to have the gene to have a 50 percent chance of passing on the RET mutation to a child. Someone who has the mutated RET gene has nearly a 100 percent chance of developing medullary thyroid cancer. 

In some cases, a new mutation can occur when there is no family history of a condition. About 50 percent of the people who have MEN2B do not have a family history of the condition. About 95 percent of the people who have MEN2A do have a family history of the condition.

Risk Factors

A risk factor is anything that increases a person's chance of getting a disease. Different diseases have different risk factors. Some risk factors can be controlled with lifestyle changes. Other risk factors cannot be changed. 

The largest risk factor for developing MEN2 is having a family history of it. If you carry the RET mutation, you have nearly a 100 percent chance of developing the associated conditions sometime in your life. 

Having one or more of the above risk factors does not mean that you will develop MEN2 syndrome. Understanding your risk factors will help you determine, what, if any, precautions and special screening you should consider.

Treatment

If a child is found to have the RET mutation, surgery to remove the thyroid to prevent cancer is strongly recommended. Medullary thyroid cancer can develop in patients at a young age, so a total thyroidectomy (removing the entire thyroid) is recommended by age three in children with MEN2B and by age six in children with MEN2A or FMTC. 

The exact treatment for MEN2 depends on the type and what endocrine glands are affected.