EPO and diabetic retinopathy: The findings with the strongest statistical evidence include variants on the promoter region of the EPO gene encoding for erythropoietin [rs1617640, p-value = 2.7 × 10−11 (37)], as well as in the SLC19A3 gene encoding for a high-affinity thiamine (vitamin B) transporter [rs12694743, p = 2.30 × 10−8 (38)], both associated with a combined phenotype of kidney failure and diabetic retinopathy.