Inheritance: autosomal dominant
Gene affected: RET proto-oncogene (causes germline activation)
Features seen in 100% of patients:
(1) medullary carcinoma of the thyroid
Features seen in 50% of patients:
(1) unilateral or bilateral pheochromocytomas
Features seen in 10-15%:
(1) parathyroid adenoma or other tumor, usually associated with hypercalcemia
Mixed disorders (rare):
(1) with cutaneous lichean amyloidosis (CLA, a pruritic cutaneous lesion distributed over the upper trunk)
(2) with Hirschsprung's disease
Causes of death:
(1) metastatic medullary carcinoma, which may occur in infancy
(2) hypertensive crisis due to the pheochromocytoma
Laboratory tests may include:
(1) serum calcitonin, for medullary carcinoma
(2) plasma metanephrines, for pheochromocytoma
(3) 24 hour urine for catecholamines or metanephrines, for pheochromocytoma
(4) serum calcium or parathyroid hormone (PTH), for parathyroid adenoma
Once a family has been identified, family members are tested for RET mutations.
