Genetic variation in C-reactive protein (CRP) gene is associated with retinopathy and hypertension in adolescents with type 1 diabetes

•We analyzed the c CRP gene polymorphism in patients with T1D.•CC genotype is associated with a decreased risk of T1D and hypertension.•CT genotype is associated with an increased risk of T1D but a decreased risk of retinopathy.•TT genotype is associated with an increased risk of retinopathy and hypertension.•T allele is associated with an increased risk of T1D and hypertension. Elevated concentration of CRP has been associated with the risk of diabetes as well as cardiovascular events and microvascular complications in T1D patients. We hypothesize that the +1846 C > T CRP gene polymorphism may have impact on the risk of T1D and/or its complications. We have examined 400 young patients with T1D and 250 healthy age-matched controls. The +1846 C > T CRP gene polymorphism was genotyped by ARMS–PCR method. The analysis covers microvascular complications, concentrations of serum pro- and anti-inflammatory markers, adhesion molecules, proangiogenic factor as well as blood pressure. CT genotype (OR = 1.799) and T allele (OR = 1.733) are associated with increased risk of T1D, while CC genotype decreases the risk of this condition (OR = 0.458). Moreover, increased risk of hypertension corresponds with TT and T variant (OR = 3.116 and OR = 1.830, resp.) while CC genotype is decreasing the risk (OR = 0.547). Furthermore, CT variant is connected with lower risk of retinopathy (OR = 0.512) whereas TT variant decreases the risk of this complication (OR = 2.228). Our data also implies various effects of CRP +1846 C > T polymorphism on the inflammatory status of T1D patients. Although further studies are required, the +1846 C > T CRP gene polymorphism could be considered a genetic marker to predict susceptibility to retinopathy and hypertension in T1D adolescents.