He came to our hospital for examination, and the reports showed recently diagnosed diabetes (fasting plasma glucose 309 mg/dl, HbA1C 14.9%) with elevated carcinoembryonic antigen (CEA) 8.9 ng/ml (normal range 0–5 ng/ml) and carbohydrate antigen 19-9 (CA19-9) 123 U/ml (normal range 0–37 U/ml). The gene discussed is CEACAM5; the disease is diabetes mellitus.