The data we collected from the GTEx database have shown that, compared with individuals homozygous for the C or G alleles, individuals homozygous for the T allele actually have a low level of ADORA2A mRNA in their blood cells (Supplementary Fig. 2), indicating that in Charles’s study, the observation that type 1 diabetic patients have a low risk of developing PDR is very likely due to a low level of ADORA2A expression in their retinal ECs. This evidence concerns the gene ADORA2A and type 1 diabetes mellitus.