Pseudohypoparayhyroidism (PHP) is a rare autosomal dominant or recessive genetic disorder characterized by low calcium, high phosphorus, and target organ resistance to parathyroid. The clinical characteristics and genetic features in 4 patients with Type Ib PHP in the Third Xiangya Hospital, Central South University, have been reviewed. All 4 patients had low calcium, high phosphorus, and parathyroid resistance. Among them, 2 patients had slightly elevated thyroid stimulating hormone and mild features of Albright's hereditary osteodystrophy, and one patient had hypokalemia. No guanine nucleotide-binding protein alpha-stimulating activity polypeptide 1 (GNAS) and gene variant associated with hypokalemia were identified using the whole exome sequencing. The results of the methylation-specific multiple ligation-dependent probe amplification showed that there were abnormal methylation of the upstream differentially methylated regions of GNAS in the 4 patients. There were phenotype overlap among the various subtypes of PHP. Detection of GNAS gene methylation in patients with clinical suspicion of Type Ib PHP is helpful for the diagnosis and treatment of PHP.
Humans ; Chromogranins/genetics* ; GTP-Binding Protein alpha Subunits, Gs/genetics* ; Hypokalemia ; Calcium ; Pseudohypoparathyroidism/genetics* ; Phosphorus

OBJECTIVE: To explore the genetic etiology of a Chinese pedigree affected with pseudohypoparathyroidism. METHODS: Peripheral blood samples of the proband and his parents were collected and subjected to trio-whole exome sequencing (trio-WES). Candidate variants were verified among the pedigree and 50 randomly selected healthy individuals through analysis of restriction fragment length polymorphism. Short tandem repeat (STR) linkage analysis was used to verify the parental origin of the pathogenic variants. RESULTS: Trio-WES and Sanger sequencing showed that the proband and his mother had both harbored a c.121C>G (p.His41Asp) variant of the GNAS gene, which was not found in other family members and the 50 healthy controls. The variant was not found in international databases. Based on guidelines from the American College of Medical Genetics and Genomics, the variant was predicted to be likely pathogenic. CONCLUSION The novel c.121C>G variant of the GNAS gene probably underlay the disease in this pedigree. Above finding has enriched the spectrum of GNAS gene variants.
Female ; Humans ; Pedigree ; East Asian People ; Mothers ; Exome Sequencing ; Pseudohypoparathyroidism/genetics* ; Mutation ; China ; Chromogranins/genetics* ; GTP-Binding Protein alpha Subunits, Gs/genetics*