OBJECTIVES: I. Identify latent hypoparathyroidism in normocalcemic adult survivors with repaired conotruncal cardiac defects, by evaluating parathyroid gland secretory function after induced hypocalcemia.

II. Determine the relationship of parathyroid hormone secretion to microdeletions in the same region of chromosome 22q11 as found in patients with DiGeorge anomaly.

PROTOCOL OUTLINE:

Patients are given sodium citrate over a 2 hour infusion on day 1. Blood is drawn at times -30, -15, 0, and every 10 minutes thereafter during the infusion. On day 2, patients are given calcium gluconate over a 2 hour infusion. Blood is drawn at times -30, -15, 0, and every 10 minutes thereafter during the infusion.

• Diagnostically shown repaired or palliated conotruncal cardiac defects, including tetralogy of Fallot with pulmonary stenosis or pulmonary atresia, truncus arteriosus, or interrupted aortic arch type B