While dark microglia were previously reported at adulthood in several mouse models of pathology (e.g., prenatal and maternal immune activation, middle-aged APP-PS1, chronic stress, CX3CR1 knockout, R6/2 model of Huntington’s disease; [64, 78, 94, 105, 106]), their presence in the human brain had yet to be reported. Here, APP is linked to juvenile Huntington disease.