Pseudohypoparathyroidism type 2

Other Names: PHP2; PHP II

Pseudohypoparathyroidism type 2 (PHP2) is a type of pseudohypoparathyroidism (PHP) characterized by resistance to parathyroid hormone (PTH), which manifests with hypocalcemia, hyperphosphatemia and elevated PTH levels, absence of Albright's hereditary osteodystrophy (AHO), and normal expression of the Gs protein with a normal urinary cAMP response.

Epidemiology

The prevalence is unknown.

Cause

To date, no specific genetic alteration responsible for this disorder has been detected. It has been hypothesized that in most cases it may be an acquired defect secondary to vitamin D deficiency such as in misdiagnosed secondary renal hyperparathyroidism.

Signs and symptoms

The clinical manifestations of PHP-2 have been poorly characterized but are similar to those seen in pseudohypoparathyroidism type1b (PHP-1b). Patients present with symptoms related to low levels of calcium including: seizures;, tetany (including muscle twitches and hand and foot spasms), numbness cataracts, and dental problems. Unlike PHP-1b, those with PHP-2 demonstrate a normal urinary cAMP response.

For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. 100% of people have these symptoms

• Pseudohypoparathyroidism

80%-99% of people have these symptoms

• Elevated circulating parathyroid hormone level
• Hyperphosphatemia(High blood phosphate levels)

30%-79% of people have these symptoms

• Hypocalcemic seizures(Low calcium seizures)

5%-29% of people have these symptoms

• Abdominal symptom
• Hypocalcemic tetany
• Laryngeal dystonia
• Muscle spasm
• Myoclonic spasms
• Paresthesia(Pins and needles feeling)
• Prolonged QT interval

Diagnosis

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

Treatment

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).

NIH genetic and rare disease info

• NIH info on Pseudohypoparathyroidism type 2

Pseudohypoparathyroidism type 2 is a rare disease.