The current study aimed, for the first time, to assess the expression of exosomal miR-34a in the serum of children and adolescents with T1DM and to evaluate the association between exosomal miR-34a expression and markers of dyslipidemia, such as total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides (TG), as well as the serum levels of markers of endothelial dysfunction, including serum endoglin and intracellular adhesion molecule (ICAM). The gene discussed is ENG; the disease is type 1 diabetes mellitus.