<prompt> Commonest cause for hyperparathyroidism isSingle adenomaMultiple adenomasSingle gland hyperplasiaMultiple gland Hyperplasia  <response>: A parathyroid adenoma causes the affected gland to release more PTH than it should. This disrupts your calcium and phosphorus balance. This condition is called hyperparathyroidism. Ref ganongs review of medical physiology 25e 