Quantitative studies demonstrated significantly less mRNA and protein levels of CD200 and CD200R in the inferior temporal gyrus and hippocampus (brain regions that show significant AD pathology) from the neuropathologically confirmed AD samples; however, a similar result was not observed in cerebellum samples – an encephalic region that is spared of AD pathology in general (Walker et al., 2009). The gene discussed is CD200R1; the disease is Alzheimer disease.