Pseudohypoparathyroidism

Albright hereditary osteodystrophy; Types 1A and 1B pseudohypoparathyroidism; PHP

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

If you have PHP, 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.

PHP is caused by abnormal genes. There are different types of PHP. 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 also involves low blood calcium and high blood phosphate levels. People with this form do not have the physical traits common to people with Type Ia. The genetic abnormality that causes it is not known.

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)

People 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

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

Other tests may include:

• Genetic testing
• Head MRI or CT scan of the brain

Your health care provider 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).

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

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

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

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

Contact your provider if you or your child have any symptoms of a low calcium level or pseudohypoparathyroidism.