PRKN and Parkinson disease: Moreover, these differences intensified as the mice aged to 17 months (IL-1α, p = 0.015; IL-1β, p = 0.014; parkin, p = 0.028); wild-type littermates of the PD-APP mice showed no elevation in the levels of any of the mRNA products measured to indicate IL-1α, IL-1β, and parkin synthesis, age-related or otherwise.