Triton X-100/Nonidet P-40 extracts from the frontal cortex of AD and ND subjects were also fractionated on sucrose density gradients and resolved by Western blotted under denaturing conditions in order to characterize the full-length 420 kDa Reelin and the two N-terminal 310 and 180-kDa fragments. Here, RELN is linked to Alzheimer disease.