Intriguingly, previous reports have demonstrated neuronal PDGFRβ expression in the rat CNS [44], whereas our work in progress in the adult human CNS and Alzheimer's disease patients shows a pericyte-restricted pattern of PDGFRβ expression [Winkler EA, Bell RD, Zlokovic BV, unpublished results] indicating that species-specific differences in PDGFRβ expression may indeed exist and that the present mouse models on a 129S1/SvlmJ background could be potentially used as correlates for human studies on brain pericytes. The gene discussed is PDGFRB; the disease is early-onset autosomal dominant Alzheimer disease.