Fifty‐four unrelated probands were selected based on the following criteria: age of diagnosis ≤17 years, family history of diabetes in at least two generations, anti‐GAD/ICA negative, BMI<95.p and follow‐up with diet, oral antidiabetic drug or low‐dose insulin treatment (≤0·5U/kg/d). This evidence concerns the gene GAD1 and diabetes mellitus.