Hypoparathyroidism is a rare condition in which the parathyroid glands fail to produce sufficient amounts of parathyroid hormone or the parathyroid hormone produced lacks biologic activity. The parathyroid glands are part of the endocrine system, a network of glands that secrete hormones into the bloodstream which then travel to various areas of the body. Parathyroid hormone (along with vitamin D and the hormone calcitonin, which is produced by the thyroid gland) plays a role in regulating the levels of calcium and phosphorus in the blood. Due to a deficiency of parathyroid hormone, individuals may exhibit abnormally low levels of calcium in the blood (hypocalcemia) and high levels of phosphorus (hyperphosphatemia). The common practice in treating these patients is with calcium and Vitamin D supplements at high doses in addition to other various drugs to treat the symptoms.
Hypoparathyroidism is one of the only hormone deficiency diseases that as of Dec. 2014 had no hormone replacement treatment. In recent years PTH injections have been studied and shown to be effective and in January 2015 a PTH injection was approved in the United States by the FDA. Although commercial PTH injections may be used as a treatment, an oral form of PTH would be significantly advantageous in treating this chronic condition. Studies conducted by NIH researchers have shown that multiple dosing is significantly more effective than a single dose in treating hypoparathyroidism.