Definition of the MEN Syndromes

MEN stands for "Multiple Endocrine Neoplasia". The MEN syndromes are conditions which cause over-activity and enlargement in certain endocrine glands.  MEN syndromes are usually (but not always) inherited conditions and therefore they run in families. When they are inherited, they are passed from one generation to the next.

There are three main types of multiple endocrine neoplasia (MEN) -MEN 1, MEN 2a and MEN 2b. Each type of MEN is associated with a specific cluster of illnesses.  Physicians use the term "syndrome" when clinical diseases come in groups of three.  Each of the three types of MEN syndromes, therefore, have three diseases. The main health problems in each of the MEN syndromes are:

  • MEN 1   =  Parathyroid tumors, pancreatic tumors, and pituitary tumors.
  • MEN 2a   =  Medullary thyroid cancers (MTC), pheochromocytoma, and parathyroid tumors.
  • MEN 2b   =  Medullary thyroid cancers, pheochromocytoma and neuromas.

There are specific genetic causes for each of the three types of MEN. Any particular MEN family will have only one type of MEN, either MEN 1, MEN 2a or MEN 2b. Therefore, families with one type of MEN do not have an increased risk of developing an other type of MEN.

What it Means to be a Genetic Disease

Each cell in the body contains many thousands of genes which determine every aspect of body function. Every person is made up of the genes they receive from there parents at the time of conception. Half of a person's genes come from their mother and half from their father. People with MEN inherit an abnormality (mutation) in one specific gene (that's why they only get one type of MEN syndrome, and their children are at risk only for that same MEN syndrome). Only people who inherit an abnormality in one of the specific MEN genes can develop MEN.

If a person has MEN, each of their children has a 50% chance of inheriting the condition. This means each child of a person with MEN has an equal chance of either inheriting or not inheriting the disease. For example, if a person with MEN has two children, the odds are one will be affected. Similarly, if a person with MEN has six children the odds are three will inherit the disease. Inherited diseases in which the likelihood of an affected person passing a disease to their children is 50%, are known as autosomal dominant diseases. A person with a family history of MEN cannot pass MEN to their children unless they themselves have inherited MEN. Only people with an MEN gene mutation are able to pass the condition to their children. Therefore, if your parents have MEN and you do not, your children will not get the disease.

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