PZP and early-onset autosomal dominant Alzheimer disease: Whether or not PZP contributes to the clearance of the Aβ peptide in vivo is currently unknown; however, it has been demonstrated that PZP levels are elevated in women with presymptomatic Alzheimer's disease and PZP is found colocalised with microglia around Aβ plaques in the brain in Alzheimer's disease [83, 84].