TAP1 and Alzheimer disease: Although TAP1 and TAP2 polymorphisms did not affect susceptibility to AD (Table 2), the TAP1 rs1135216 heterozygote decreased the mean age at diagnosis to 14 years, whereas such age was higher for rs1135216*T/T (19.64 years, Table 3; C/C homozygote was rare, see Table 2).