COQ2 p.V393A variant, rs148156462, is not associated with Parkinson's disease in a Taiwanese population

Association of the COQ2 V393A variant with risk of multiple system atrophy in East Asians: a case-control study and meta-analysis of the literature

Recent studies in Japan have associated multiple system atrophy (MSA), a neurodegenerative disease of uncertain etiology, with polymorphism in the COQ2 gene. This led us to explore whether the same polymorphism is associated with MSA in Han Chinese and more broadly in East Asians. We conducted a case-control study with 82 Han Chinese with probable MSA and 484 gender- and age-matched healthy subjects, genotyping them using the ligase detection reaction. The results were meta-analyzed together with data from four previous studies to gain a broader picture of possible disease associations in East Asian populations. The COQ2 variants M78V and R337X were not detected in our Han Chinese patients or controls; only the heterozygous V393A variant (CT genotype) was detected. The frequency of this genotype was significantly higher in patients (7.3%) than in controls (1.86%; OR 4.17, 95% CI 1.44-12.04, p = 0.004). Subgroup analysis among patients showed a significant association of V393A with MSA involving cerebellar signs (MSA-C; OR 4.59, 95% CI 1.36-15.48, p = 0.007), but not with MSA involving parkinsonism (MSA-P). Meta-analysis of our results in Han Chinese with data from case-control studies in Japan, Korea, mainland China and Taiwan showed a significant association of V393A with MSA (OR 2.05, 95% CI 1.29-3.25, p = 0.002), which subgroup analysis showed to be significant for MSA-C (OR 2.75, 95% CI 1.98-3.84, p < 0.001) but not for MSA-P (OR 1.25, 95% CI 0.64-2.46, p = 0.51). These findings provide evidence that the previously reported association of COQ2 V393A polymorphism with increased risk of MSA in Japanese also applies to Han Chinese, as well as more broadly to other East Asian populations. This association may be particularly strong for MSA-C.

Association of the COQ2 V393A Variant with Parkinson's Disease: A Case-Control Study and Meta-Analysis

Both Parkinson's disease (PD) and multiple system atrophy (MSA) are neurodegenerative diseases of uncertain etiology, but they show similarities in their pathology and clinical course. The fact that the gene encoding α-synuclein is associated with both diseases also suggests that they share some genetic determinants. Recent studies in Japan associating MSA with a variant in the COQ2 gene led us to question whether variants in the COQ2 gene are associated with PD in Han Chinese in a case-control study. A total of 564 patients with PD were genotyped using the ligase detection rection, together with 484 gender- and age-matched healthy subjects. The M128V and R387X variants of COQ2 were not detected in patients or controls; instead, we detected only the heterozygous V393A variant (CT genotype). The frequency of the CT genotype encoding the V393A mutation was significantly higher in patients PD (4.08%) than in controls (1.86%), corresponding to an odds ratio of 2.24 (95%CI 1.03 to 4.90, p = 0.037). The frequency of the C allele of the V393A variant was significantly higher in patients with PD than in controls (OR 2.22, 95%CI 1.02 to 4.82, p = 0.039), and this was also observed in a meta-analysis of studies from mainland China, Taiwan and Japan. Subgroup analysis of our data showed that the V393A variant was significantly associated with early-onset PD (OR 3.71, 95%CI 1.51 to 9.15, p = 0.002) but not with late-onset disease (OR 1.65, 95%CI 0.69 to 3.95, p = 0.260). Gender was not significantly associated with either genotype or minor allele frequencies. In conclusion, our findings show for the first time that the V393A variant in the COQ2 gene increases risk of PD among the population of east Asia. These results, combined with research on Japanese, lend genetic support to the hypothesis that oxidative stress underlies pathogenesis of both PD and MSA.

Association Analysis of COQ2 Variant in Dementia and Essential Tremor

Objective. COQ2 mutations have been reported in Japanese multiple system atrophy (MSA) patients. We examined the role of COQ2 in patients with dementia and essential tremor (ET), two common neurodegenerative conditions. Materials & Methods. A total of 2064 subjects, including 560 patients with dementia, 466 patients with ET, and 1038 healthy controls, were included. Genotyping for the COQ2 V393A (T>C) was carried out. Odds ratio (OR) adjusted by age and gender, together with 95% confidence interval (CI), was reported by means of logistic regression. Results. The frequency of the polymorphic variant V393A heterozygous (T/C) was 2.7% in dementia, 1.1% in ET, and 2.5% in controls (OR = 0.70, 95% confidence interval is 0.29-1.72 for dementia, and OR = 0.47, 95% confidence interval is 0.17-1.31, p = 0.1217 for ET). There was no significant association between V393A variant with dementia and ET. Conclusion. There was no significant association between V393A variant with dementia and ET. COQ2 gene is unlikely to play a significant role in patients with dementia or ET in our population.