LRRK2 and Parkinsonism: Previous research has estimated the heritability of Parkinson’s disease at 22%, with PRS explaining approximately a quarter of this heritability within the European population.16 Furthermore, PRS has been linked to an elevated risk of Parkinson’s disease in carriers of the LRRK2 p.G2019S mutation, particularly noting a stronger association in cases of early-onset LRRK2 parkinsonism.50 Interestingly, variants in MAPT5 have been reported to increase risk of Parkinson’s disease in LRRK2 variant carriers.