In addition, increased expression of α-synuclein by astrocytes may also be a feature of PD as astrocytes generated from PD-iPSC (i.e. mutant LRRK2 cases) in the absence of neurons exhibit much higher levels of endogenous α-synuclein expression than astrocytes generated from control-iPSC cases [62]. Here, SNCA is linked to Parkinson disease.