Endocrine Abstracts

Introduction: Most cases of Diabetes mellitus (DM) in children and adolescents are autoimmune (type 1), even though recently there has been an increase in type 2 DM mainly due to the increased prevalence of obesity in this age group. However, rarely DM could be attributed to other causes such as MODY. An extremely rare cause is the hereditary pancreatitis due to activating mutations of the PRSS1 gene. This gene encodes an enzyme, cationic trypsinogen, whose hyperactivity leads to prolonged intrapancreatic effect of trypsin. This destructive process of pancreatic tissue results in diabetes, recurrent pancreatitis and pancreatic cancer. .

Case presentation: A 16–year old male adolescent presented to our department with typical diabetic symptomatology. He was in good general condition without ketoacidosis. Fasting glucose was 266 mg/dL and HbA1c 10.9%. The antibodies for type 1 DM were negative with the exempt of those against the zinc transporter ZnT8. C–peptide was measurable although inappropriately low for his high blood glucose. Despite the high HbA1c, the patient was treated with metformin and lifestyle modification resulting in excellent metabolic control (fasting blood glucose 80–120 and 2 hours postprandially < 140 mg/dl). Further genetic investigation for MODY, especially MODY3 which is the most common form, was negative. Subsequent screening for other types of DM revealed an activating mutation of the PRSS1 gene.

Conclusion: When the diagnosis of type 1 diabetes mellitus in children and adolescents cannot be established with safety and genetic testing for MODY is negative, screening for PRSS1 gene mutations must be performed. If the result is positive, additional counseling should be pursued regarding the nature and progression of this hereditary disease as well as the future possibility of pancreatic cancer.