After stratification of the patients included in the presented study according to the carried genotype, we discovered a significantly lower serum level of 1.25-dihydroxy vitamin D in the high-risk CAD patients compared with the low-risk ones, with the A/A–A/G genotypes of the rs2228570 polymorphism of the VDR gene (33.17 pg/mL vs. 67.47 pg/mL), the A/A genotype of the rs7041 polymorphism (12.36 pg/mL vs. 72.39 pg/mL) and the A/A genotype of the rs2298849 polymorphism (36.43 pg/mL vs. 73.24 pg/mL) of the GC gene (Table 5). The gene discussed is VDR; the disease is coronary artery disorder.