PCP4 and Down syndrome: Dysregulated PCP4 expression was described in the context of neuronal disorders such as Alzheimer disease (Slemmon et al., 1994; Recabarren and Alarcón, 2017), Huntington disease (Utal et al., 1998), major depressive disorder (Teyssier et al., 2011), and Down syndrome (Cabin et al., 1996; Chen et al., 1996) and related to alterations in the prefrontal cortex of individuals suffering from alcohol abuse (Iwamoto et al., 2004).