The −3826A/G polymorphism of UCP1 was further reported to be associated with diabetic retinopathy (DR) in DM1 group and the UCP1 gene expression was increased in human retina [16]; while the same polymorphism of UCP1 (−3826A/G) was not found the association with DM2 with European ancestry in another study [17], although a significant association between the UCP2 Ala55Val and UCP3 −55C/T polymorphisms and increased susceptibility for DM2 were detected in Asians in the same study [17]. Here, UCP1 is linked to diabetic retinopathy.