ARRB2 and neurodegenerative disease: Importantly, a cluster of proteins involved in the development of the substantia nigra, including myelin basic protein (MBP), beta-arrestin-2 (ARRB2) and tubulin beta-4A chain (TUBB2A), were isolated in those participants who experienced DKA at diagnosis, possibly linking T1D with neurodegenerative diseases such as Parkinson’s disease in adulthood.