Pseudohypoparathyroidism (PHP) is a heterogeneous group of endocrine disorders characterized by normal renal function and resistance to the action of parathyroid hormone (PTH), manifesting with hypocalcemia, hyperphosphatemia and elevated PTH levels and that includes the subtypes PHP type 1a (PHP-1a) , PHP type 1b (PHP-1b), PHP type 1c (PHP-1c), PHP type 2 (PHP-2) and pseudopseudohypoparathyroidism (PPHP) (see these terms).