A Young Diabetic Case with Bloom Syndrome

Bloom syndrome (BS) is a rare autosomal recessive disorder characterized by short stature, telangiectasias, and a rash on the face triggered by the sun. Other clinical features include immune deficiency and predisposition to the development of cancer and diabetes. We present this case as the diabetic BS is rare. Case: A 20-year-old male patient who had diabetes for 3 years was admitted. The patient had complaints of rash on sun-exposed parts of the body such as cheeks and arms since he was 2 years old. In his medical history, he was found to be followed up for growth failure. His parents had a cousin marriage. The diepoxybutane test was performed as BS was suspected due to sun-induced rashes, growth failure, and telangiectasias. The chromosome analysis showed that our case had 40 breakages per 100 metaphases, whereas there were 2 breaks in control. Immunoglobulin levels were low. BS was diagnosed with phenotypic findings. The physical examination revealed rashes and telangiectasias on the face. He was 152 cm and 49 kg. In the oral glucose tolerance test (OGTT) of 3 years earlier, fasting plasma glucose (FPG) was found to be 125 mg/dL and in the 2nd hour of the test, plasma glucose was 295 mg/dL and fasting insulin was 57.73 IU/mL. He was diagnosed with diabetes according to OGTT. The laboratory findings of our patient who was on metformin were: FPG 91 mg/dL, hemoglobin A1c 6%, and basal insulin 29.3 IU/mL. In the follow-ups, metformin was observed to regulate his blood glucose levels. Results: Diabetes is diagnosed in 10% of patients with BS, most often type 2 diabetes. BS is caused by mutations in the BLM gene on chromosome 15q26.1. The genomic instability characterized by mutations and the elevated rate of sister chromatid exchange lead to tendency to malignancy. These patients should be closely followed for malignancy and development of diabetes.