In each cell of the body there are 23 pairs of chromosomes that contain our genes. We inherit one chromosome from each pair from each parent. This means that we inherit one copy of each gene from each of our parents, thereby giving us two copies. In most people there are two normal functioning genes associated with MEN syndromes. In patients with an MEN syndrome, one of this pair has a change (mutation). This can be inherited from either parent (inherited or familial) or can start in an individual for the first time (new mutation or de novo). When someone with MEN has children they can pass on either the normal gene or the gene change. This is entirely random, like tossing a coin. Each child therefore has a 1 in 2 or 50% chance of inheriting the gene change (coloured blue, right), and is therefore at risk of developing the tumours in an MEN syndrome. This method of inheritance is called autosomal dominant inheritance.

It is possible in some families to have a genetic test to see whether someone has inherited the gene change. The first step is to have a blood sample tested from someone with the MEN syndrome in the family. With this first test (mutation screen), the result may not be received for a number of months, and, indeed, a gene change is not always found. If a gene change is found, a blood test (predictive genetic testing) may then be offered to other members of the family. The results from predictive genetic testing are often received within several weeks. There are a number of issues surrounding predictive genetic testing particularly in relation to children and as such, all patients should be seen and counselled by a consultant clinical geneticist. If a gene change cannot be found or if a blood sample from an affected person cannot be obtained then predictive genetic testing cannot be done.

Having children tested is a very individual decision, however; if children of a parent with a known MEN syndrome gene change are tested and do not have that gene change they can rest assured that no further tests are needed. Those who have inherited the gene can be comforted by the fact that a screening plan will find and treat any tumours as early as possible. In this way, problems caused by the syndrome, may be drastically reduced.

Genetic testing and counselling is available and a referral to a genetic centre is usually made through your GP or specialist.

The Generation Study is a long-term research study being run by Genomics England in partnership with NHS England.

The study involves collecting a blood sample after birth and aims to understand if they can improve how genetic conditions are diagnosed and treated by looking at the DNA of newborn babies.

The Study will sequence and analyse the genomes of 100,000 newborn babies in England to look for certain treatable genetic conditions, with treatment options available through the NHS in England.  From March 2026, mutations in the RET gene that cause MEN type 2B (MEN2B or MEN3) will be included in the study.

It is important to stress that the process to diagnosis through the study occurs in two distinct steps:

Screening

A way of identifying apparently healthy people who may have an increased risk of a particular condition.

Diagnosis

The process of identifying a condition from its signs, symptoms and test results.

We have a short presentation from Genomics England with more information on the study which you can download below.

If the gene mutation causing an MEN syndrome is known, then it is sometimes possible to have Preimplantation Genetic Testing (PGT) as a way to avoid having a child affected with the MEN syndrome.

To find out more about Family planning including methods of conception and other considerations surrounding these, please refer to our booklet, Starting a Family.