As with all endocrine disorders the abnormalities seen are associated either with overproduction or underproduction of the relevant hormone. The two main abnormalities are therefore:
1. Hyperparathyroidism - excessive production of parathyroid hormone.
2. Hypoparathyroidism - Reduced production of parathyroid hormone.
Both states can be caused by a variety of conditions and give a large range of symptoms and even none at all. They are dealt with in detail in their own sections.