In conclusion, at variance from what already known, in this large kindred the Cys609Ser RET mutation predispose to a scarcely aggressive, highly penetrant MTC and a low penetrance of pheochromocytoma and primary hyperparathyroidism.
Multiple endocrine neoplasia 2A due to a unique C609S RET mutation presents with pheochromocytoma and reduced penetrance of medullary thyroid carcinoma.