In this study, the MASLD group with PNPLA3 genotypes CC and CG had decreased gut Blatuia and Ruminococcaceae, suggesting that decreased short-chain fatty acids, such as acetate and butyrate, may contribute to obesity, and increased blood glucose and triglyceride levels, which may contribute to the onset and progression of MASLD. The gene discussed is PNPLA3; the disease is obesity due to melanocortin 4 receptor deficiency.