TREM2 and Alzheimer disease: Another brain biochemical endophenotype GWAS locus with AD and other neuropsychiatric disease-related associations was NPAS3-APOETX which is also associated with neuritic and diffuse plaque measurements [93], CSF levels of soluble TREM2 [94], epistatic interactions with tau measurements [89], schizophrenia [95, 96] and bipolar [95, 97, 98] disorder.