Perhaps a more interesting ontological category is the 11 downregulated genes associated with MAPK signaling pathway, a number of which (Arrb2, Cacna1g, Fgfr4, Taok1, Cacna1h) have been implicated in Alzheimer's disease (AD) (49–53). Here, TAOK1 is linked to early-onset autosomal dominant Alzheimer disease.