There were genetic associations between four variants (G2019S, G2385R, R1628P and A419V) and increased PD risk, while there was no evidence of statistically significant association between P755L and PD.
Given these findings, it was quite reasonable to suppose that LRRK2 Pro755Leu variant rarely increased risk for PD in ethnic Chinese population in Asia.
The phenotype of patients with PD with the P755L variant was generally similar to other patients with PD and none of the carriers reported a positive family history.
To further evaluate the role of LRRK2 P755L variant in sporadic PD, we performed direct sequencing of LRRK2 exon 19 in 501 Japanese sporadic PD patients (male 249, female 252, aged 28-92 years, mean 65.0 years) and 583 controls of the Japanese general population as an extended association study.
Therefore, we conclude that LRKK2 P755L variant is a rare cause of Caucasian PD and has no diagnostic utility in genetic testing of this population of patients.