J Korean Soc Pediatr Endocrinol.
1998 Nov;3(2):219-227.
Two Cases of Pseudohypoparathyroidism
Abstract
- Pseudohypoparathyroidism(PHP) is a genetic disorder characterized by target cell resistance to the effect of parathyroid hormone(PTH). The disorder is classified into type I a, I b, I c and II depending on the phenotype and biochemical findings. In type I a, urinary cyclic AMP and urinary phosphate excretion are not increased after PTH stimulation because of deficient G unit activity in target cells. Deficiency of the G unit is a generalized cellular defect and accounts for the association of other endocrine disorders with type I a PHP. Type I b PHP shows resistance to PTH but not to other hormones and normal phenotypic appearance. In type I c PHP affected children have defect in catalytic unit of adenylate cyclase and in addition to resistance to PTH, resistance to the metabolic effects of TSH, gonadotropins, and glucagon may be detected. Typical appearance of Albright's hereditary osteodystrophy is common in PHP type Ia and Ic. In type II PHP, urinary cyclic AMP response is generated but this does not lead to phosphaturia. We experienced two patients with PHP. One is a 11-year-old girl diagnosed type I a PHP and the other is a 11-year-old boy suspected type I b PHP. They visited emergency room because of tetanic movement. Both patients had no previous history of tetany and showed low serum calcium level, high phosphorus level and high PTH level. The girl had typical features of Albright's hereditary osteodystrophy such as round face, short neck, obese feature, brachydactyly and mental retardation but didn't have basal ganglia calcification on brain CT. The boy showed normal appearance and no mental retardation.
