GCK and MODY: Previous studies indicate that GCK-MODY2, HNF1A-MODY3, HNF4A-MODY1 and HNF1B-MODY5 account for more than 95% cases of MODY in Caucasians, but only account for just 10–20% of MODY cases in Asia (including China, Japan and Korea) (15).