LRRK2 I2020T mutation is associated with tau pathology

Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are the most common cause of autosomal-dominant familial Parkinson's disease (FPD). The variable pathological features of LRRK2-linked FPD include Lewy bodies, degeneration of anterior horn cells associated with axonal spheroids, neurofibrillary tangles (NFTs) and TAR DNA-binding protein of 43 kDa (TDP-43) positive inclusion bodies. Furthermore, abnormal hyperphosphorylation of microtubule associated protein tau, in part generated by catalysis of protein kinases, has been reported to be involved in progressive neurodegeneration in a number of diseases, including FPD. Thus, we examined six patients carrying the LRRK2 I2020T mutation, a pathogenic mutation associated with PARK8, and found abnormal tau phosphorylation depositions in the brainstem. Additionally, we found LRRK2 I2020T enhanced tau phosphorylation in cultured cells co-expressing LRRK2-I2020T and 3 or 4-repeated tau. This is the first report describing the relationship between hyperphosphorylation of tau and LRRK2 I2020T.