LRRK2 and Parkinson disease: Our data clearly show that the LRRK2 p.Arg1067Gln variant activates LRRK2 kinase pathway activity, in vivo in peripheral blood monocytes from an affected variant carrier with PD compared to a control, as well as in a robust cellular overexpression system that allows evaluation of LRRK2 variant effect on LRRK2 kinase function.