| [ Summary ] |
Pseudohypoparathyroidism (PsH) is characterized by the biochemical abnormalities of hypoparathyroidism (hypocalcemia and hyperphosphatemia), increased serum PTH levels, and resistance to exogenous PTH. PsH is classified into several subtypes (types Ia, Ib, Ic and II) according to differences in pathogenesis, laboratory findings and clinical features. The majority of patients belong to type I PsH which is caused by a defective cAMP signaling system. Physical characteristics such as short stature, brachydactyly and round face, termed as Albright's hereditary osteodystrophy, are often seen in patients with type I PsH. The differential diagnosis of PsH includes other forms of hypoparathyroidism and pseudo-PsH (Albright's hereditary osteodystrophy without hypoparathyroidism). Patients with PsH can be successfully treated with active vitamin D [1,25(OH)2D3, or its analog, 1-alphaOH D3]. |