Cytoband (human 11q13.1 MEN1).
Multiple endocrine neoplasia (MEN) is a group of inherited disorders that cause tumors to develop in several hormone-producing (endocrine) glands. These tumors can be benign (noncancerous) or malignant (cancerous) and often lead to an overproduction of hormones, which can cause a wide range of health issues.
Main Types of MEN Syndromes.
There are two primary types of MEN, each defined by the specific glands and genes involved:
- MEN Type 1 (MEN1): Also known as Wermer syndrome, it most commonly affects the “3 Ps”:
- Parathyroid Glands: Causes hyperparathyroidism, leading to high blood calcium, kidney stones, and bone thinning.
- Pancreas/Duodenum: Can cause gastrinomas (leading to stomach ulcers) or insulinomas (causing low blood sugar).
- Pituitary Gland: Often results in prolactinomas, which can affect fertility and vision.
- MEN Type 2 (MEN2): Caused by mutations in the RET gene and is divided into subtypes:
- MEN2A (Sipple Syndrome): Characterized by medullary thyroid cancer (MTC), adrenal tumors (pheochromocytomas), and sometimes parathyroid overgrowth.
- MEN2B: A more aggressive form featuring early-onset MTC, pheochromocytomas, and physical traits like mucosal neuromas (bumps on the tongue/lips) and a “Marfanoid” (tall, slender) body type.
- MEN Type 4 (MEN4): A rare, newer classification with symptoms very similar to MEN1 but caused by a mutation in the CDKN1B gene.
Causes and Inheritance
MEN is an autosomal dominant condition, meaning it is passed down through families. If one parent carries the mutated gene, each child has a 50% chance of inheriting it.
- MEN1: Caused by a mutation in the MEN1 gene (menin protein), which normally prevents tumors from forming.
- MEN2: Caused by a mutation in the RET gene, which helps control cell division.
