Tags: Disease.
Hypoparathyroidism is decreased function of the parathyroid glands with underproduction of parathyroid hormone. This can lead to low levels of calcium in the blood often causing cramping and twitching of muscles or tetany (involuntary muscle contraction) and several other symptoms. The condition can be inherited but it is also encountered after thyroid or parathyroid gland surgery and it can be caused by immune system-related damage as well as a number of rarer causes.