Familial (Genetic) Endocrine Disorders
What is Multiple Endocrine Neoplasia?
Specific genetic abnormalities can lead to the development of endocrine tumors. One of the most common of these genetic abnormalities is Multiple Endocrine Neoplasia (MEN). MEN is broken into different groups depending on the specific mutation. Patients with MEN type 1 (MEN 1) are prone to get tumors of their pituitary gland, parathyroids and pancreas. Patients with MEN type 2 (MEN 2) are further divided into two sub-groups MEN 2A and MEN 2B.
Patients with MEN 2A get tumors in their thyroid (medullary thyroid cancer), parathyroid and adrenal glands (pheochromocytomas). Patients with MEN 2B get tumors in their thyroid (medullary thyroid cancer), adrenal glands (pheochromocytomas) and often have small benign tumors on their lips, tongue and eyelids. Often patients with MEN 2B also have a “marfanoid” body habitus, which means they are tall and thin with long hands.
MEN syndromes are autosomal dominant which means that they are past down from a single parent and that each offspring has a 50% chance of getting the disease.
My mom/dad/sister/brother had papillary thyroid cancer and so do I. Does this mean we have a familial predisposition?
Family history is a risk factor for papillary thyroid cancer, but represents the minority of cases. The risk of a familial papillary thyroid cancer increases with the more family members that are affected. When a single additional family member has papillary thyroid cancer, then risk of a familial syndrome is about 40%. When 3 or more family members are affected then the risk increases to 99%. Some families have rare syndromes that predispose them to colon and thyroid cancers.
My mom/dad/sister/brother had hyperparathyroidism and so do I. What does that mean?
Family history is a risk factor for primary hyperparathyroidism. This may put you at increased risk of having more than one enlarged parathyroid gland (multiple gland disease). Some families have a condition call familial hypocalciuric hypercalcaemia where the calcium receptor in the parathyroid and kidney does not work properly. These patients do no benefit from parathyroidectomy.