TNFRSF1A and Alzheimer disease: Specifically, the genes for TNFR1 and TNFR2 reside on chromosome 1p and chromosome 12p, respectively and these regions show genetic linkage to late-onset AD; in addition, a genetic polymorphism in exon 6 of the TNFR2 gene was associated with late-onset AD, while no significant association was found between AD and three genetic polymorphisms in the TNFR1 gene [170].