Multiple Endocrine Neoplasia Type 1 is a rare genetic disorder associated with a high risk of developing tumors in your parathyroid gland and pituitary gland, and your pancreas.
Multiple endocrine neoplasia type 1 (MEN1) is one of the majority subdivisions of multiple endocrine neoplasia (MEN), along with MEN2 and the very rare MEN4.
Almost everybody with MEN1 develops parathyroid cancer at some point. Your parathyroid glands are four small glands in your neck that help regulate calcium levels in your blood.
Many people with MEN1 also develop tumors in other glands and require regular monitoring so that treatment can be initiated quickly.
Let’s examines MEN1 in more detail, including how it compares to MEN2, what types of cancer it’s associated with, and how it’s treated.
Multiple endocrine neoplasia type 1 vs. type 2
MEN1 and MEN2 are the two major subcategories of MEN. They both increase your risk of developing certain cancers but have different associated cancers and gene mutations. Here’s a look at how they compare.
| Feature | MEN1 | MEN2 |
|---|---|---|
| gene mutation | MEN1 | RET |
| prevalence | 1 in 30,000 people | 1 in 35,000 people |
| associated tumors and conditions | • parathyroid tumors • primary hyperparathyroidism (high parathyroid hormone levels originating from the parathyroid gland) • gastrointestinal neuroendocrine tumors • pituitary tumors | • medullary thyroid cancer (MTC) • pheochromocytoma • parathyroid tumors |
Mutations in the CDKN1B gene cause a rarer form of MEN called MEN4. Very few cases have been reported, and the associated tumors tend to be similar to MEN1.
MEN1 is a genetic disorder caused by genes inherited from your parents. It’s caused by a dominant gene, which means you only need to receive an associated gene mutation from one parent to develop MEN1.
If one of your parents has a gene for MEN1, you have a 50% chance of developing MEN1 too.
Sometimes, MEN1 mutations develop sporadically with no known cause or family history.
Initial symptoms of MEN1 involving the parathyroid glands often appear in your
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People with parathyroid tumors might develop
- kidney stones
- muscle weakness
- tiredness
- increased thirst and urination
- depression
- aches and pains
- digestive problems like constipation
Other symptoms might include:
- stomach ulcers
- acid reflux
- abdominal pain
- frequent diarrhea
- low blood glucose
- enlarged and swollen hands and feet
People with MEN1 have a high risk of developing tumors and health problems related to abnormally high hormone levels caused by these tumors.
Parathyroid tumors
Almost everyone with MEN1 develops thyroid tumors. These tumors can cause the overproduction of parathyroid hormone and high levels of calcium in your blood.
Gastrointestinal tumors
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- Gastrinomas: Gastrinomas produce the hormone gastrin and cause your stomach to release too much acid.
- Insulinomas: Insulinomas form in your pancreas in cells that produce the hormone insulin and cause blood sugar problems.
- Glucagonomas: Glucagonomas cause cells in your pancreas to produce too much glucagon and can also cause blood sugar problems.
- ViPomas: ViPomas cause cells in your pancreas to produce the hormone vasoactive intestinal peptide and may cause problems like
watery diarrhea .
Pituitary tumors
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Other tumors
Some people develop other tumors, such as:
- adrenal gland tumors
- carcinoid tumors in places like the stomach, thymus, or lungs
- tumors involving the skin or tissue under the skin, such as:
- lipomas
- angiofibromas
- collagenomas
- meningiomas, which are tumors that start in the meninges
It’s important to seek medical help if you develop signs of MEN1 like symptoms potentially related to high calcium levels. It’s also important to get your child screened for an associated gene mutation if you have a known family history.
Doctors can diagnose MEN1 if you meet one of the following
- two or more MEN1-related tumors
- one MEN1-related tumor and a first-degree relative (child, sibling, parent) with a diagnosis
- a MEN1 mutation even if you don’t have signs or symptoms
Genetic testing is usually performed with a blood test, but some labs may use a cheek swab or saliva.
MEN1 doesn’t have a cure. Treatment aims to reduce complications of tumors and associated hormonal imbalances. Some treatment options include:
| Tumor type | Potential treatments |
|---|---|
| parathyroid tumors | • medications to reduce symptoms • surgery to remove the tumor • freezing or burning of tumors spread to your liver • chemotherapy |
| tumors of the pancreas or digestive tract | • medications to reduce symptoms • surgery to remove the tumor • freezing or burning of tumors spread to your liver • chemotehrapy |
| pituitary gland tumors | • medications to shrink the tumor • surgery to remove the tumor • less commonly, radiation therapy |
MEN1 is associated with reduced survival, but many people still live full or near-full lives. The outlook for people with MEN1 is highly
Metasized pancreatic tumors (those that have spread to other organs) are the leading cause of death in people with MEN1. The development of these tumors is associated with a poorer outlook.
The main factors linked to better survival are early diagnosis and treatment.
There’s no known way to prevent MEN1 since it’s caused by genes passed through your family. Following your doctor’s screening and treatment recommendations can help you improve the course of your disease.
MEN1 is a rare genetic condition that’s associated with a high risk of developing some types of tumors such as those in your parathyroid gland, pituitary gland, and gastrointestinal tract.
There’s no way to prevent MEN1. Many people can live long lives with a high quality of life by receiving regular screening and proper treatment. Your or your child’s doctor can best advise you on strategies to maximize the outlook of MEN1.