Clinical and functional evidence for the pathogenicity of the LRRK2 p.Arg1067Gln variant

Abstract LRRK2-related Parkinson’s disease (LRRK2-PD) is the most frequent form of monogenic PD worldwide, with important therapeutic opportunities, exemplified by the advancement in LRRK2 kinase inhibition studies/trials. However, many LRRK2 variants, especially those found in underrepresented populations, remain classified as variants of uncertain significance (VUS). Leveraging on Malaysian, Singaporean, and mainland Chinese PD datasets (n=4,901), we describe 12 Chinese-ancestry patients harbouring the LRRK2 p.Arg1067Gln variant, more than doubling the number of previously reported cases (total n=23, 87% East Asian, mean age of onset:53.9years). We determine that this variant is enriched in East Asian PD patients compared to population controls (OR=8.0, 95%CI:3.0-20.9), and provide supportive data for its co-segregation with PD, albeit with incomplete penetrance. Utilizing established experimental workflows, this variant showed increased LRRK2 kinase activity, by ~2-fold compared to wildtype and higher than the European p.Gly2019Ser variant. Taken together, p.Arg1067Gln should be reclassified from a VUS to pathogenic for causing LRRK2-PD.