Pseudohypoparathyroidism

抄録

Pseudohypoparathyroidism (PHP) is composed of PHP-Ia and PHP-Ib. The former is characterized by multiple hormone resistance including parathyroid hormone associated with Albright hereditary osteodystrophy (AHO); but in the latter, AHO is not complicated. In the natural course of PHP-Ia, the time of onset, the degree of hypocalcemia and associated symptoms vary among patients. Since the symptoms of AHO, including brachydactyly, are often ambiguous, the criteria for clinical differential diagnosis between these two types are required. In our 10 cases of sporadic PHP-Ib, no patient had subcutaneous calcification. Currently, however, genetic analysis on the DNA methylation is necessary for the definite diagnosis. All of the 10 cases of sporadic PHP-Ib had complete methylation in NESP55 as well as complete demethylation in the AS and 1A regions of the GNAS gene, while the region of the abnormal methylation in XL were varied among the patients. There was no clear correlation among skewed X-inactivation, abnormal DNA methylation pattern, clinical phenotypes and other complications.