CD44 and Alzheimer disease: The previous research proved that most of them were involved in nervous diseases, for example, GAD1 was involved in the neuropathology of schizophrenia [21], RGS4 showed decreased mRNA levels in the prefrontal cortex from AD patient autopsies [47], CD44 was increased in lymphocytes derived from AD patients [39], and the FOS exhibited the intensification of immunoreactivity in AD cases [48].