Pseudohypoparathyroidism is a rare target tissue anti-PTH disorder with hypocalcemia, hyperphosphatemia biochemical changes and clinical changes of parathyroidism. Although some patients are clinically indistinguishable from primary parathyroidism, measurement of increased iPTH confirms the diagnosis. In addition, most patients have abnormal physical manifestations, also known as Albright’s hereditary osteodystrophy (AHO). Mental retardation is also common in patients with hypothyroidism, adrenalism, hypogonadism, diabetes mellitus, and uremia. It is also commonly referred to as pseudohypoparathyroidism type I and type II. In type I, the target organ is defective in the cell membrane and cannot form adenylate cyclase in response to PTH. In type II, the target organ can produce adenylate cyclase, but due to an intracellular defect in the later procedure, the target organ cannot respond to cAMp, so the generated cAMP cannot have further physiological effects and urinary phosphorus excretion is not increased. Both type I and type II pseudohypoparathyroidism can be associated with AHO or without AHO, and because the target organ response can be partially lost, it can be further divided into subtypes that are bone-responsive and kidney-unresponsive, and bone-unresponsive and kidney-responsive. These are described below. Pseudohypoparathyroidism type I: It is usually divided into two types, Ia and Ib. Pseudohypoparathyroidism type Ia: Etiology and pathogenesis
The main cause is a mutation in the Gsa gene, which leads to a decrease in the function of Gsa protein formation. The differential expression of the Gsa protein gene can lead to impaired activation of cAMP by PTH and can cause AHO and various endocrine defects. Human
Gsa protein gene is a complex 20Kb gene localized at 20q13.2. Mutations can produce abnormal Gsa
mRNA and cause disease. The disease is inherited in an autosomal dominant or recessive manner. Diagnostic points This type is the most common form of pseudohypoparathyroidism. The clinical manifestations are as follows. Clinical manifestations 1. Hypocalcemia symptoms: hand-foot convulsions, seizure-like episodes, cataracts, lack of tooth enamel, delayed tooth eruption, and calcification of the basal ganglia. Among them, hand-foot twitching is mild. 2. Special physical signs: short (height)