The concentration of FGF19 protein was lower in children with T1D than in the control group (226.52 ± 18.95 pg/mL vs. 240.08 ± 23.53 pg/mL, p = 0.003), and also sklotho protein concentrations in T1D group were lower than in the control group (2448.67 ± 791.92 pg/mL vs. 3083.55 ± 1113.47 pg/mL, p = 0.011). This evidence concerns the gene FGF19 and type 1 diabetes mellitus.