Taking the background presented into consideration, we conducted this study with the aim of evaluating the effects of SNPs in the genes involved in the vitamin D pathway (CYP27B1, CYP24A1, GC and CYP2R1) and in the gene encoding its receptor, VDR (ApaI, BsmI, FokI, TaqI and Cdx2), on the risk of developing asthma. Here, CDX2 is linked to asthma.