Nasiri-Kalmarzi R, et al. - As a part of this study, the vitamin (Vit) pathway and the link between vitamin D receptor (VDR) and vitamin D binding protein (VDBP) gene polymorphisms and chronic urticaria (CU) risk were assessed in this trial, among Iranian cohort. It was deduced that the change in vitamin D (Vit D) pathway in the level of gene or protein could serve as a risk factor for the progression of CU.