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). The gene discussed is FGFR4; the disease is early-onset autosomal dominant Alzheimer disease.