Clinical and Genetic Study of Pseudohypoparathyroidism Type 1b in Hong Kong Chinese

Abstract

Pseudohypoparathyroidism type 1b (PHP-1b) is a rare congenital imprinting disease characterized by parathyroid hormone resistance, normal neurodevelopment and no feature of Albright hereditary osteodystrophy. It is caused by genetic and epigenetic defect of GNAS locus located at chromosome 20q13.32 region. We here have reported a case series of three cases of PHP-1b in Hong Kong Chinese. Two were sporadic and one was autosomal dominant (AD) subtype. All of them were identified by methylation specific-multiplex ligation dependent probe amplification method. The AD PHP-1b case had typical 3-kb STX16 gene deletion. There was no paternal uniparental disomy chromosome 20 for those sporadic cases. Although PHP-1b had been well studied in western population, it is rarely reported in Chinese. This study is the first comprehensive study of PHP-1b for Hong Kong Chinese in the literature. With more awareness and better understanding of PHP-1b, it will result in judicious use of genetic testing and better medical management of this orphan disease.




J Endocrinol Metab. 2016;6(2):64-70
doi: http://dx.doi.org/10.14740/jem337w