Neuronal pentraxin-2 (NPTX2), a protein involved in inhibitory circuit dysfunction [10], is a promising biofluid surrogate marker of inhibitory circuit dysfunction and cognitive decline in sporadic AD [11–13], vascular dementia [14], genetic frontotemporal dementia [15], and Lewy body dementia [16]. This evidence concerns the gene NPTX2 and Lewy body dementia.