High Frequency of SERPINA6 Polymorphisms that Reduce Plasma Corticosteroid-Binding Globulin Activity in Chinese Subjects

Context: Cortisol is transported by corticosteroid-binding globulin (CBG) in blood. Single nucleotide polymorphisms (SNP) in the human CBG (SERPINA6) gene that disrupt CBG production or steroid binding are considered rare. Objective: The objective of the study was to identify and determine the frequency of SNP in SERPINA6 that influence the production or cortisol-binding properties of CBG in Chinese subjects. Participants and Design: Blood samples from 2287 anonymous Chinese workers undergoing routine health tests were screened for the SERPINA6 coding sequence polymorphisms. Main Outcome Measures and Results: In a pilot study of 108 Chinese women, two nonsynonymous SNP were identified within SERPINA6 exon 2 encoding CBG A51V (n = 3) and CBG E102G (n = 1) variants. Sequence analysis of SERPINA6 exon 2 in a further 137 Chinese women revealed two other individuals with nonsynonymous SNP encoding CBGs R64Q and R64W as well as another CBG A51V carrier. The surprisingly high frequency of heterozygous CBG A51V c...