Type I MEN involves all, except –
**Core Concept**
Type I Multiple Endocrine Neoplasia (MEN) is a rare hereditary disorder characterized by the development of tumors in multiple endocrine glands, primarily the parathyroid glands, pancreas, and pituitary gland. It is caused by mutations in the MEN1 gene, which encodes a tumor suppressor protein.
**Why the Correct Answer is Right**
Type I MEN typically involves hyperparathyroidism due to parathyroid gland tumors, pancreatic neuroendocrine tumors (PNETs), and pituitary adenomas. The MEN1 gene mutations lead to the loss of function of the tumor suppressor protein, resulting in uncontrolled cell proliferation and tumor formation. The parathyroid glands are often the first to be affected, leading to hypercalcemia.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not a characteristic of Type I MEN.
**Option B:** This option is incorrect as Type I MEN does not typically involve medullary thyroid carcinoma.
**Option C:** This option is not a correct association with Type I MEN.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that Type I MEN can be diagnosed using genetic testing for the MEN1 gene mutation, and affected individuals should undergo regular screening for tumors in the parathyroid glands, pancreas, and pituitary gland.
**Correct Answer: B. Medullary thyroid carcinoma is more commonly associated with Type II MEN.**