Association of glucokinase gene and glucokinase regulatory protein gene polymorphisms with gestational diabetes mellitus: A case–control study

•GCK rs1799884 polymorphism was associated with increased GDM risk in Chinese population.•Regulation of histones might affect the functional expression of human islet cells.•The sample size was large and potential confounders were controlled.•There were 6 candidate gene loci, which expanded the research scope of corresponding genes.