A subset of Rab GTPases closely connected with late onset PD were identified as substrates of LRRK2 (Steger et al., 2016), suggesting that in PD induced by TBI, TBI may elevate the expression of Rab proteins in brain and then increase disrupted LRRK2 substrates in glial cells and neurons which finally lead to PD. The gene discussed is RAB6A; the disease is Parkinson disease.