HTT and nervous system disorder: Interestingly, the most connected hubs also included amyloid beta precursor protein (APP), a single pass transmembrane protein expressed in the brain whose accumulation generates the characteristics plaques found in the brains of patients with Alzheimer’s disease (O’Brien and Wong, 2011); and huntingtin (HTT), a disease gene linked to Huntington’s disease, a monogenic neurological disorder characterized by the dysfunction and death of neurons (Bates et al., 2015).