CTSB and Alzheimer disease: It was found that lysosomes containing saposins and lysosome-associated membrane protein (LAMP1) accumulate in dystrophic neurites (DNs) surrounding Aβ plaques during the early stages of AD, but lysosomal hydrolases (e.g., CTSB and CTSBD) were not detected in these early DNs, implying that these lysosomes may be malfunctioning lysosomes.