TGFB1 and exfoliation syndrome: TGF-β1 has also been suggested to play an important role in the pathogenesis of glaucoma [39,40], and higher levels of the TGF-β1 isoform occur most commonly in XFG [41]; however, it has been suggested that high IOP itself may induce the expression of activated TGF-β1 in TM cells [42].