More specifically, the TGF-β2 levels in the AH were shown to be significantly higher in PPCD1 patients (d = 106.0 pg/ml, P = 0.0005) and in PPCDx patients (d = 216.6 pg/ml, P = 0.0022), as compared to the controls. This evidence concerns the gene TGFB2 and posterior polymorphous corneal dystrophy 1.