pediatrics
Diabetes Mellitus in Children and Adolescents
Etiology of Diabetes in Children and Adolescents
Most patients are categorized as having type 1 or type 2 diabetes, and this distinction is used to guide treatment. Classification is based on clinical history (age, family history, body habitus), presentation, and laboratory studies, including antibodies. However, this classification system does not fully capture the clinical heterogeneity of patients, and some patients cannot clearly be classified as having type 1 or type 2 diabetes at diagnosis. In both type 1 and type 2 diabetes, genetic and environmental factors can result in the progressive loss of beta-cell function that results in hyperglycemia. because of autoimmune destruction of pancreatic beta-cells, possibly triggered by an environmental exposure in genetically susceptible people. Close relatives are at increased risk of diabetes (about 15 times the risk of the general population), with overall incidence 4 to 8% (30 to 50% in monozygotic twins). Children with type 1 diabetes are at higher risk of other autoimmune disorders, particularly thyroid disease and Celiac Disease . Inherited susceptibility to type 1 diabetes is determined by multiple genes (> 60 risk loci have been identified). Susceptibility genes are more common among some populations and explain the higher prevalence of type 1 diabetes in certain ethnic groups (eg, Scandinavians, Sardinians). Intype 2 diabetes,the pancreas producesinsulin, but there are varying degrees ofinsulinresistance, andinsulinsecretion is inadequate to meet the increased demand caused byinsulinresistance (ie, there isrelativeinsulindeficiency). Onset often coincides with the peak of physiologic pubertalinsulinresistance, which may lead to symptoms of hyperglycemia in previously compensated adolescents. The cause is not autoimmune destruction of beta-cells but rather a complex interaction between many genes and environmental factors, which differ among different populations and patients. Although type 2 diabetes is different than type 1 diabetes, type 2 diabetes in children is also different than type 2 diabetes in adults. In children, decline in beta-cell function and development of diabetes-related complications are accelerated. Risk factors for type 2 diabetes include Obesity Native American, Black, Hispanic, Asian American, and Pacific Islander heritage Family history (60 to 90% have a 1st- or 2nd-degree relative with type 2 diabetes) Monogenic forms of diabetesare caused by genetic defects that are inherited in an autosomal dominant pattern, so patients typically have one or more affected family members. Unlike type 1 and type 2 diabetes, there is no autoimmune destruction of beta-cells orinsulinresistance. Onset is usually before age 25 years. 