PKD2 and diabetic retinopathy: Although we should be cautious regarding this hypothesis, it was previously reported that transgenic rats with overexpression of a mutant cilia gene, polycystin-2, exhibited similar specific phenotypes to diabetic retinopathy, such as vasoregression and pericyte loss [44]: furthermore, in the same transgenic rats, streptozotocin-induced chronic hyperglycemia was shown to ameliorate vasoregression and neuroglia cell loss [45], in agreement with the finding of a weaker association between RP1-90L14.1 and PDR than with DR (Table 3).