Conditions and Treatments

Multiple Endocrine Neoplasia Type 1 (MEN1) - What it is

Multiple Endocrine Neoplasia Type 1 is a hereditary tumour/cancer syndrome.

What is Multiple Endocrine Neoplasia Type 1?

Multiple Endocrine Neoplasia Type 1 (MEN1) is a hereditary condition associated with an increased risk of tumours of the endocrine (hormoneproducing) glands.

These glands are located in different parts of the body and control the production of hormones that direct many body processes, including growth, digestion and sexual function.

MEN1 is caused by a fault (i.e., mutation) in the MEN1 gene. The gene provides instructions for producing a protein called menin which is known to play a role in keeping cells from growing and dividing too fast.

How common is MEN1?

It is estimated that about one in 30,000 people have MEN1.

The majority of individuals with MEN1 inherit the condition from a parent.
About 10% of people with MEN1 do not have a family history of the condition. This is because they may have acquired a de novo (new) change or fault in the MEN1 gene at birth.

What are hereditary tumours and cancers?

Hereditary tumours and cancers develop because of the presence of a faulty gene. Some genes function to protect us from tumour/cancer growth. When they are not working well, it causes an increased risk for tumours/cancers to grow. We refer to genes that are not working well as faulty genes.

Individuals who carry a faulty tumour/cancer gene(s) have a higher chance of developing certain tumours/cancers over their lifetime compared to the general population. The types of tumours/cancer that they may be at increased risk of will depend on the gene(s) involved.

If you have a faulty tumour/cancergene, you may be at increased risk of developing certain tumours/cancers. As genes are shared among family, other family members may have inherited the faulty gene and may be at increased risk of tumours/cancer too.

What is genetic testing?

Genetic testing is offered to individuals where a hereditary cause of their personal and/or family history of tumours/cancer is suspected.

Genes contain the instructions that our body reads to carry out different functions. Genetic testing involves analysing your genes to understand if there are faults (i.e., mutations) that may increase the risk of tumours/cancer.

How is genetic testing done?

Genetic testing is typically a one-time blood test.
If a blood sample cannot be taken, other sample sources (e.g., skin or saliva) may be used.

What are the possible results of genetic testing?

There are 3 types of results you may receive:

Positive	Uncertain - Variant of Uncertain Significance (VUS)	Negative
Faulty gene(s) identified	Uncertain gene change(s) identified, unclear if these change(s) increase risk for tumours and cancers	No faulty gene(s) identified
Increased risk of developing certain tumours and cancers (depends on faulty gene(s) involved)	May be clarified by testing other family members	Tumour and cancer risk is similar to that of general population
Your family (parents, siblings, children and extended relatives) may have inherited the faulty gene(s) and should consider genetic testing to clarify this	May be reclassified over time as ‘positive’ or ‘negative’ when more information is known	Test limitations will be explained in the context of your personal and family history of tumours and cancers