In the context of MEN 1 syndrome, which gland is primarily affected?

In the context of Multiple Endocrine Neoplasia type 1 (MEN 1) syndrome, the parathyroid glands are primarily affected. MEN 1 is characterized by a triad of endocrine tumors that commonly include hyperparathyroidism due to parathyroid adenomas, pancreatic islet cell tumors, and pituitary tumors. Among these, hyperparathyroidism occurs in approximately 90% of patients with MEN 1, leading to elevated levels of parathyroid hormone (PTH) and subsequently hypercalcemia.

This condition usually presents in young adulthood, and the manifestations of parathyroid hyperplasia or adenomas often go undetected for years until symptoms of hypercalcemia, such as kidney stones, osteoporosis, or abdominal discomfort, become apparent.

While the pancreas and adrenal glands can also be involved in MEN 1—pancreatic tumors can lead to various hormonal disturbances and adrenal tumors may cause excess catecholamines—the hallmark endocrine manifestation of this syndrome is the disorder affecting the parathyroid glands.