Pseudohypoparathyroidism is a genetic disorder in which the body is unable to respond to parathyroid hormone. Parathyroid hormone helps control calcium, phosphorous, and vitamin D levels in the bones and blood. Hypoparathyroidism is a similar condition in which the body does not make enough parathyroid hormone instead of not being able to respond to it (as in pseudohypoparathyroidism).

The symptoms of these two conditions are similar and are caused by low calcium levels and high phosphate levels in the blood. This may cause cataracts (clouding of the lens of the eye), dental problems, numbness, seizures, or tetany (muscle twitches and hand and foot spasms). These symptoms are usually first seen in childhood.

There are two different types of pseudohypoparathyroidism, both of which are caused by spelling mistakes (mutations) in certain genes. Type 1 can be further divided into three sub-types.