[Pseudohypoparathyroidism].

Pseudohypoparathyroidism (PsH) is a disease (or syndrome) characterized by biochemical abnormalities of hypoparathyroidism, increased serum PTH levels and the resistance to exogenous PTH. Since the first description of this disease by Albright et al, there has been substantial progress in understanding the pathogenesis of PTH resistance and the genetic basis for this disease. The differential diagnosis includes other forms of hypoparathyroidism, especially idiopathic hypoparathyroidism. Normocalcemic PsH, a rare and atypical subtype, has to be differentiated from pseudo-PsH (Albright's hereditary osteodystrophy without hypoparathyroidism). This review discusses current concepts and classification of PsH (types I a, I b, I c and II) and the recent demonstration of genetic defects in patients with type I a or I b of PsH. The pathophysiology and treatment of PsH will also be discussed.