Preliminary screening of mutations in the glucokinase gene of Chinese patients with gestational diabetes

AIMS/INTRODUCTION Mutations in the glucokinase gene (GCK) are a pathogenetic cause of maturity-onset diabetes of the young. Studies have found that female patients with GCK maturity-onset diabetes of the young often present with gestational diabetes during pregnancy. Our aim was to preliminarily assess the prevalence of mutations in the glucokinase gene in Chinese women with gestational diabetes. MATERIALS AND METHODS Chinese gestational diabetes patients who underwent a 100-g oral glucose tolerance test in Peking Union Medical College Hospital from July 2005 to May 2008 were retrospectively analyzed. Participants were selected for direct sequencing of the GCK gene if they met the following criteria: (i) fasting plasma glucose between 5.5 and 10.0 mmol/L; and (ii) a small increment (<4.6 mmol/L) during a 2-h oral glucose tolerance test. RESULTS Of the 501 participants with gestational diabetes, there were 38 participants who met the criteria for GCK analysis. In the 29 participants whose deoxyribonucleic acid samples were available, two mutations in coding regions were detected, c.626 C>T (p.T209M, NP_000153.1) mutation in exon 6 and c.824 G>A (p.R275H, NP_000153.1; rs767565869) mutation in exon 7. According to our results, the minimum prevalence of GCK mutations in Chinese women with gestational diabetes was estimated to be 0.4%, and the minimum prevalence of GCK maturity-onset diabetes of the young in the Chinese population might be one in 2,000. CONCLUSIONS Our screening criteria allowed for the identification of glucokinase-deficient patients who were diagnosed with gestational diabetes, and these mutations in the GCK gene were not common in Chinese women with gestational diabetes.