Cinacalcet to Treat Familial Primary Hyperparathyroidism

This study will evaluate safety and efficacy of short- and long-term Cinacalcet in treatment of hypercalcemia of familial primary hyperparathyroidism. The study population will include patients with primary hyperparathyroidism caused by multiple endocrine neoplasia type 1 or type 2A. This is a prospective unblinded pilot study, where each patient will serve as his/her own control. It will include 6 one-week-long admissions, over a 1 year period. Main measurements will be tests of hyperparathyroidism such as parathyroid hormone and serum calcium as well as tests of nonparathyroid tumors. The latter tests may include hormones released by the tumors and images of the tumors.