In co-culture experiments of induced pluripotent stem cell (iPSC)-derived astrocytes and ventral midbrain DA neurons (vmDAns) from familial mutant LRRK2 G2019S PD patients and healthy individuals, accumulated α-syn was observed in control astrocytes when co-cultured with PD vmDAns, demonstrating the direct neuron-to-astrocyte transfer of α-syn [202]. Here, LRRK2 is linked to Parkinson disease.