ABSTRACT
We present two cases with “Maturity-onset diabetes of the young” (MODY) undergoing bariatric surgery. Case 1: a 19-year-old woman using intensive insulin for type 1 diabetes mellitus (DM) was diagnosed with obesity. Body mass index (BMI) was 39.17 kg/m2, fasting blood glucose (FBG) was 199 mg/dL, postprandial blood glucose (PPBG) was 239 mg/dL, glycated hemoglobin (HbA1c) was 11.1%, Cpeptide (Cp) was 1.53 ng/mL, and antiGAD and ICA (islet cell autoantibody) were negative. Genetic analysis revealed a heterozygous mutation in HNF1A (MODY 3). We performed Roux-n-Y gastric bypass (RYGB). She discontinued insulin. Case 2: A 33-year-old woman using intensive insulin because of type 2 DM was diagnosed with obesity. BMI was 44.4 kg/m2. FBG was 195 mg/dL, PPBG was 269 mg/dL, HbA1c was 9.4%, Cp was 1.89 ng/mL, and ICA and AntiGAD were negative. Genetic analysis revealed heterozygous mutation in KCNJ11 (MODY 13). RYGB was performed with an indication of morbid obesity. She discontinued insulin. RYGB was performed first in our cases for MODY. Improvement in glycemic regulation was higher than expected. A decision on bariatric surgery in patients with MODY should be made on the basis of the degree of obesity and glycemic status.