Pancreatic beta-cells function and anti-insulin antibodies in children with down syndrome

ABSTRACT

Down syndrome has been linked with many autoimmune disorders. Type 1 diabetes mellitus is more prevalent in Down syndrome. The autoimmune etiology of type 1 diabetes mellitus has been well documented after the discovery of insulin autoantibodies in newly diagnosed diabetics and in individuals at high risk for type 1 diabetes mellitus. The aim of this work was to assess pancreatic beta-cells function and presence of anti-insulin antibodies in children with Down syndrome for possibility of occurrence of pancreatic dysfunction before development of overt diabetes mellitus. The study was carried out on twenty Down syndrome children aged from 4 to 15 years, none of them had history of diabetes mellitus or other autoimmune disease. Ten age and sex matched apparently healthy children with normal karyotyping served as controls. All of them were subjected to full history taking and thorough clinical examination followed by assessment of anti-insulin antibodies with blood glucose and C-peptide levels at fasting state, 2 minutes, 30 minutes and an hour after intravenous infusion of glucose 10% [5 ml/kg body weight] as a challenge test. The results showed that two girls with Down's syndrome had anti-insulin antibodies levels above the cut- off point of anti-insulin antibodies 1> 10.09 u/ml]. The first one, aged 4 years, had fasting blood glucose level 124mg/dl then 140mg/dl one hour after infusion. Her fasting C- peptide level was 0.8ng/ml then 1.ing/ml after one hour of the intravenous glucose tolerance test. The second girl, aged 14 years, had fasting blood glucose 118mg/dl then 130mg/dl one hour after glucose infusion. Her fasting C-peptide was 0.9ng/ml then 1.7 after one hour of the intravenous glucose infusion. Female children had significantly higher blood glucose level at fasting state and one hour after glucose infusion. There was significant proportional correlation between anti-insulin antibodies and blood glucose level at lasting state, two minutes, half an hour and one hour after intravenous glucose infusion and significant inverse correlation were found between it and C-peptide levels at fasting state , two minutes and half an hour after the challenge test