Conversely, gut microbiota dysbiosis leads to a significant reduction in SCFA production, which may disrupt the balance between pro-inflammatory CD4+IL-17+ T cells and anti-inflammatory CD4+ FOXP3+ Treg cells in the gut, promoting abnormal differentiation of Th17 cells and the release of pro-inflammatory factors such as IL-17 and IL-22, thereby inducing tissue inflammation (110), potentially contributing to the onset of AD and AA. The gene discussed is CD4; the disease is Alzheimer disease.