Fyn phosphorylates the N-methyl-D-aspartate (NMDA) receptor subunit 2B (NR2B) and facilitates its interaction with postsynaptic density protein 95 (PSD95).22 The NR2B/PSD95 interaction is essential in Aβ-induced neurotoxicity.23 As increased neuronal membrane cholesterol is an important factor in AD and also causes overexpression of Fyn gene, this could be the link between cholesterol, Aβ and tau.24 The gene discussed is FYN; the disease is Alzheimer disease.