LRRK2 was shown to be upregulated in the brains of patients with PD, but there is no significant difference in the expression level of LRRK2 mRNA between the control and PD cases, indicating the overexpression of LRRK2 may be induced by post-transcriptional modification of LRRK2 mRNA in PD brains. Here, LRRK2 is linked to Parkinson disease.