Pseudohypoparathyroidism type 1A (PHP1a) is a type of pseudohypoparathyroidism (PHP; see this term) characterized by renal resistance to parathyroid hormone (PTH), resulting in hypocalcemia, hyperphosphatemia, and elevated PTH; resistance to other hormones including thydroid stimulating hormone (TSH), gonadotropins and growth-hormone-releasing hormone (GHRH); and a constellation of clinical features known as Albright hereditary osteodystrophy (AHO; see this term).
