Pseudohypoparathyroidism type 2 (PHP2) is a type of pseudohypoparathyroidism (PHP; see this term) characterized by resistance to parathyroid hormone (PTH), which manifests with hypocalcemia, hyperphosphatemia and elevated PTH levels, absence of Albright's hereditary osteodystrophy (AHO; see this term), and normal expression of the Gs protein with a normal urinary cAMP response.
The prevalence is unknown.
The clinical manifestations of PHP-2 have been poorly characterized but are similar to those seen in pseudohypoparathyroidism type1b (PHP-1b; see this term). 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.
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.
Last update: October 2014