['We studied the association between a functionally relevant M55V polymorphism in the SUMO4 gene with microvascular diabetic complications in patients with type 1 diabetes.', '223 patients with type 1 diabetes were studied using polymerase chain reaction and subsequent cleavage by restriction endonucleases for the M55V SUMO4 gene variant.', 'No effect of the polymorphism on diabetic neuropathy or diabetic nephropathy was found, but heterozygous or homozygous patients for the M55V polymorphism in the SUMO4 gene had a markedly reduced prevalence of diabetic retinopathy (odds ratio 0.37, 95%-confidence interval (CI) [0.32;0.43]; p=0.004). Furthermore, a multiple logistic regression model showed an age and diabetes duration independent effect of the M55V polymorphisms on the prevalence of diabetic retinopathy (p=0.03), but not of diabetic neuropathy or nephropathy.'] Is a M55V polymorphism in the SUMO4 gene associated with a reduced prevalence of diabetic retinopathy in patients with Type 1 diabetes?