RELN and Alzheimer disease: Reelin expression in the central nervous system (CNS) has been implicated in a wide range of neurodegenerative diseases, such as Alzheimer’s disease (AD), cognitive disorders, such as autism spectrum disorder, and neuropsychiatric disorders, such as schizophrenia and bipolar disorder [15,27,28,29,30,31,32,33,34,35,36,37,38,39].