Northside Health Library


Pseudohypoparathyroidism

Definition

Pseudohypoparathyroidism is a genetic disorder that is similar to hypoparathyroidism. However, it is caused by the body's lack of response to parathyroid hormone instead of reduced production of the hormone.

Alternative Names

Albright's hereditary osteodystrophy; Types 1A and 1B pseudohypoparathyroidism

Causes

The parathyroid glands help control calcium use and removal by the body. They do this by producing parathyroid hormone, or PTH. PTH helps control calcium, phosphorus, and vitamin D levels in the blood and bone.

Persons with pseudohypoparathyroidism produce the right amount of PTH. However, their body is "resistant" to its effect. This causes low levels of calcium and high levels of phosphate in the blood.

Pseudohypoparathyroidism is caused by abnormal genes. All forms of this condition are very rare.

  • Type Ia causes short height, a round face, and short hand bones. It is also called Albright's hereditary osteodystrophy.
  • Type Ib involves resistance to PTH, but only in the kidneys. Type Ib is not as well understood as type Ia. It is very similar to type I, but the events that take place in the kidneys are different. 
  • Type II also involves low calcium and high phosphate levels in the blood. However, persons with this form do not develop the physical traits seen in people with type Ia.

Symptoms

Symptoms are related to low levels of calcium and include:

  • Cataracts
  • Numbness
  • Seizures
  • Tetany (a collection of symptoms including muscle twitches and hand and foot spasms)
  • Tooth problems

Persons with Albright's hereditary osteodystrophy may have the following symptoms:

  • Calcium deposits under the skin
  • Dimples that can replace knuckles on affected fingers
  • Round face and short neck
  • Short hand bones, especially the bone below the 4th finger
  • Short height

Exams and Tests

Blood tests will be done to check calcium, phosphorus, and PTH levels. Urine tests may also be done.

Other tests may involve:

Treatment

Calcium and vitamin D supplements are prescribed to maintain proper calcium levels. If blood phosphate levels remain high, a low-phosphorus diet or medicines called phosphate binders (such as calcium carbonate or calcium acetate) may be necessary.

Outlook (Prognosis)

Low blood calcium in pseudohypoparathyroidism is usually milder than in other forms of hypoparathyroidism.

Possible Complications

Patients with type Ia pseudohypoparathyroidism are more likely to get other endocrine system problems (such as hypothyroidism and hypogonadism).

Complications of low blood calcium may include:

  • Impaired sexual development
  • Low energy levels
  • Low sex drive
  • Seizures and other complications of endocrine problems
  • Weight gain

When to Contact a Medical Professional

Call your health care provider if you or your child has any symptoms of low calcium levels or pseudohypoparathyroidism.

References

Wysolmerski JJ, Insogna KL. The parathyroid glands, hypercalcemia, and hypocalcemia. In: Kronenberg HM, Schlomo M, Polansky KS, Larsen PR, eds. Williams Textbook of Endocrinology. 11th ed. St. Louis, Mo: WB Saunders; 2008:chap 266.

Bringhurst FR, Demay MB, Kronenberg HM. Disorders of mineral metabolism. In: Kronenberg HM, Schlomo M, Polansky KS, Larsen PR, eds. Williams Textbook of Endocrinology. 11th ed. St. Louis, Mo: WB Saunders; 2008:chap 27.

Doyle DA. Hypoparathyroidism. In: Kliegman RM, Stanton BM, St. Geme J, Schor N, Behrman RE, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 565.


Review Date: 7/19/2012
Reviewed By: Shehzad Topiwala, MD, Chief Consultant Endocrinologist, Premier Medical Associates, The Villages, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.
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