Polymorphism R25P in the gene encoding transforming growth factor-beta (TGF-beta1) is a newly identified risk factor for proliferative diabetic retinopathy. - Beranek,M.; Kankova,K.; Benes,P.; Izakovicova-Holla,L.; Znojil,V.; Hajek,D.; Vlkova,E.; Vacha,J. (Am J Med Genet, 2002)