Studies on animals support these conclusions: Vitamin D-supplemented MRL/lpr and pristane-induced lupus models demonstrated enhanced cognition and increased hippocampal VDR expression; in the PIL model, the review reports a positive VDR–IgG correlation (rather than decreased IgG), alongside evidence consistent with neuroinflammation modulation [104]. The gene discussed is VDR; the disease is systemic lupus erythematosus.