CTSB and obesity due to melanocortin 4 receptor deficiency: CTSB can active autophagy in obesity. Obesity promotes the hypertrophy and hyperplasia of adipocyte, and weakens the regulation of fat storage in white adipose tissue, which results in impaired lysosomal function and the release of CTSB and other proteases into the cytoplasm, leading to autophagosome accumulation and increased inflammation.