This article waslast modified on July 10, 2017.
A condition characterized by underactivity of the parathyroid glands and reduced production of parathyroid hormone (PTH), a hormone that controls calcium and phosphate levels in blood and calcium in bone. Symptoms may include tingling in the fingers and toes, muscle aches and spasms, fatigue, dry skin and brittle nails, headaches, anxiety, and depression.