Most research reports show that aging, decreased appetite, insufficient nutritional intake, vitamin D deficiency, reduced sex hormones, increased inflammatory cytokines, and overexpression of angiotensin II are the main factors in sarcopenia in early-stage CKD; uremic toxins, metabolic acidosis, lack of exercise, insulin resistance, and reduced dietary intake, nutrient losses into the dialysate, and comorbid conditions are mainly related to sarcopenia in patients treated with dialysis. This evidence concerns the gene AGT and sarcopenia.