Clinical and gene methylation analysis of type 1b pseudohypoparathyroidism

Objective This study was carried out to analyze the clinical characteristics of pseudohypopara-thyroidism(PHP) type 1b, and to improve the understanding and diagnosis of the disease. Methods Five patients with molecular diagnosis of pseudohypoparathyroidism type 1b in our hospital during 2018 were enrolled, their clinical data, biochemical indicators, imaging, and gene detection results were analyzed. Results There were 4 females and 1 male, with low calcium, high phosphorus and high PTH serum concentrations. The onset age span was large and the onset symptoms were different. Family history may not be obvious. There was abnormal methylation of GNAS gene or deletion of exon STX16 in methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) detection while gene sequencing result was negative. Conclusion MS-MLPA detection was still needed in patients with suspected PHP but negative gene sequencing result. Different methylation abnormalities and copy number variations might be correlated with the onset symptoms and familial of type 1b PHP. Key words: Pseudohypoparathyroidism, type 1b; GNAS; Methylation