The analysis of the Cathepsin S expression levels by qPCR in the frontal cortex of several neurodegenerative diseases with cortical affection indicated that Cathepsin S sCJD overexpression is not a common feature of neurodegenerative diseases, although modest increases on its expression was also detected in Parkinson Disease/Lewy Body Dementia (PD/LBD) and in early stages of AD (Fig. 8d). The gene discussed is CTSS; the disease is Alzheimer disease.