Lower calcidiol levels were observed in SLE patients carrying the CT genotype (SLE = 19.2 ng/mL vs. CS = 23.6 ng/mL; p = 0.02) (Figure 2a), the GCT/GCT (SLE = 20.2 ng/mL vs. CS = 25.1 ng/mL, p = 0.02), and AAC/GAT haplogenotypes (SLE = 16.1 ng/mL vs. CS = 23.9 ng/mL, p = 0.01) (Figure 2b), while there was no difference in the presence of the TT, CC FokI genotypes, and other VDR haplogenotypes (Figure 2a,b, Table S1). The gene discussed is VDR; the disease is systemic lupus erythematosus.