METTL3 and focal segmental glomerulosclerosis: To further investigate the clinical relevance of METTL3 in the pathogenesis of RF, we performed immunostaining on kidney biopsy specimens from 20 patients with RF due to various etiologies, including focal segmental glomerulosclerosis, IgA nephropathy, diabetic nephropathy, and membranous nephropathy (Fig. 8, A and B).