Parkinsonism (PD) is occasionally seen in several types of spinocerebellar ataxia (SCA). Mutations in SCA gene have been reported in the patients of parkinsonism without ataxia.

We examined spinocerebellar ataxia type 12 mutation in 877 PD and 199 multiple system atrophy (MSA) patients.

No patients showed abnormal SCA12 expansion. It suggests that PD and MSA are not associated with SCA12 and it is not necessary to screen SCA12 in PD and MSA patients.

A number of causative mutations such as a-synuclein, parkin, UCHL1, Pink-1, DJ-1 have been identified in Parkinson's disease (PD). They are usually found in the familial cases. One mutation of great interest is the G2019S mutation in the LRRK2 gene, which has been reported in both familial and sporadic PD. Its prevalence has been reported to vary markedly among different races. We examined the prevalence of the G2019S mutation in the Korean PD population for genetic study planning.

We conducted a genetic analysis of the G2019S mutation by standard PCR and restriction digestion method. 453 PD patients were studied, 34% of whom had an age at onset of <50 years and 3.8% had a positive family history.

None of the 453 study subjects carried the G2019S mutation.

Our result confirms previous reports that the G2019S mutation is rare among PD patients in the Asian population. This result supports the notion that the prevalence of this LRRK2 mutation is population specific, and that there may be a founder effect within western populations.