TLR2 and early-onset autosomal dominant Alzheimer disease: Toll-like receptor 2 (TLR2) represents a reasonable functional and positional candidate gene for Alzheimer's disease (AD) as it is located under the linkage region of AD on chromosome 4q [1], and is functionally involved in the microglia-mediated inflammatory response and amyloid β (Aβ) clearance [2-6].