Pseudohypoparathyroidism

 

Alternative Names

Albright hereditary osteodystrophy; Types 1A and 1B pseudohypoparathyroidism

Definition

Pseudohypoparathyroidism is a genetic disorder in which the body fails to respond to parathyroid hormone.

A related condition is hypoparathyroidism, in which the body does not make enough parathyroid hormone. 

Causes

The parathyroid glands produce parathyroid hormone (PTH). PTH helps control calcium, phosphorus, and vitamin D levels in the blood and bone.

If you have pseudohypoparathyroidism, your body produces the right amount of PTH, but is "resistant" to its effect. This causes low blood calcium levels and high blood phosphate levels.

Pseudohypoparathyroidism is caused by abnormal genes. There are different types of pseudohypoparathyroidism. All forms are rare.

  • Type Ia is inherited in an autosomal dominant manner. That means only one parent needs to pass you the faulty gene for you to have the condition. It is also called Albright hereditary osteodystrophy. The condition causes short stature, round face, obesity, developmental delay, and short hand bones. Symptoms depend on whether you inherit the gene from your mother or father.
  • Type Ib involves resistance to PTH only in the kidneys. Less is known about type Ib than type Ia. Calcium in the blood is low, but there are no symptoms of Albright hereditary osteodystrophy.
  • Type II pseudohypoparathyroidism also involves low blood calcium and high blood phosphate levels. People with this form of the disorder do not have the physical traits common to people with Type Ia. The genetic abnormality that causes it is not known.

Symptoms

Symptoms are related to a low level of calcium and include:

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

Persons with Albright 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. You may also need urine tests.

Other tests may include:

Treatment

Your doctor will recommend calcium and vitamin D supplements to maintain a proper calcium level. If the blood phosphate level is high, you may need to follow a low-phosphorus diet or take medicines called phosphate binders (such as calcium carbonate or calcium acetate).

Outlook (Prognosis)

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

Possible Complications

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

Pseudohypoparathyroidism may be connected to other hormone problems, resulting in:

  • Low sex drive
  • Slow sexual development
  • Low energy levels
  • Weight gain

When to Contact a Medical Professional

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

References

Al-Azem H, Khan AA. Hypoparathyroidism. Best Pract Res Clin Endocrinol Metab. 2012; 26:517-522.

Bringhurst FR, DeMay MB, Kronenberg HM. Hormones and disorders of mineral metabolism. In: Melmed S, Polonsky KS, Larsen PR, Kronenberg HM, eds. Williams Textbook of Endocrinology. 12th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 28.

Doyle DA. Hypoparathyroidism. In: Kliegman RM, Stanton BF, St. Geme JW III, et al., eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 565.

Review Date: 8/5/2014
Reviewed By: Brent Wisse, MD, Associate Professor of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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