Genetic Disorders of Calcium and Phosphorus Metabolism Related with Parathyroid Glands

Calcium (Ca), phosphorus (phosphate, HPO4), and magnesium (Mg) are essential nutrients that are critical for the structural integrity and functions of the body. Therefore, disorders of calcium and phosphorus metabolism lead to serious and even life-threatening consequences such as skeletal and cardiovascular morbidity. Parathyroid hormone (PTH), calcitonin, and the active form of vitamin D (calcitriol, 1,25-dihydroxyvitamin D3) hormones are the main hormones that are responsible for regulating the calcium and phosphorus level in the blood. Hypoparathyroidism is due to insufficient circulating parathyroid hormone levels characterized by hypocalcemia and hyperphosphatemia. Besides being an isolated condition or a component of a complex syndrome, the causes of hypoparathyroidism are rarely genetic. Primary hyperparathyroidism is a disorder that results in excessive, uncontrolled production of parathyroid hormone. Rarely, primary hyperparathyroidism caused by genetic disorders is associated with an inherited familial germline mutation syndrome such as familial isolated hyperparathyroidism and multiple endocrine neoplasia type 1 and type 2A. Although genetic disorders are not the most common cause of hyper/hypoparathyroidism, molecular analyses have identified an increasing number of genes that cause loss or gain of function of genes related to calcium and phosphorus metabolism.