LRRK2 and Parkinson disease: To answer this previously unaddressed question about PD pathogenesis, we quantified the multimerization of αSyn in induced pluripotent stem cell (iPSC)-derived, neurogenin-induced human neurons (called iNs) from PD patients with the most prevalent LRRK2 mutations, G2019S (referred to as LRRK2 line (L) 1 and L2 hereafter) and R1441C (referred to as lines L3 and L4).