Dysfunction in the autophagy-lysosomal pathway of neurons, as seen in diseases like Alzheimer’s, leads to exosomal uptake of lysosomal membrane proteins and lysosomal granule enzyme cathepsin D. Consequently, levels of LAMP-1 are elevated in neural-derived plasma exosomes from patients with AD compared to those without the disease, as will be commented below (Goetzl et al., 2015). The gene discussed is CTSD; the disease is Alzheimer disease.