An association analysis of the rs1572931 polymorphism of the RAB7L1 gene in Parkinson's disease, amyotrophic lateral sclerosis and multiple system atrophy in China

Background and purpose: Recently, the rs1572931 single-nucleotide polymorphism (SNP) of the putative promoter of the member RAS oncogene family-like 1 (RAB7L1) gene was reported to be associated with reduced risk for Parkinson's disease (PD) in the Ashkenazi Jewish population. Ethnic-specific effects are an important consideration in genome-wide association studies. Considering that the clinical manifestations and pathological characteristics overlap between PD, amyotrophic lateral sclerosis (ALS) and multiple system atrophy (MSA), the possible associations between the rs1572931 SNP and these three diseases were studied in the Chinese population.

Methods: A total of 1011 PD patients, 778 sporadic ALS (SALS) patients, 264 MSA patients and 516 healthy controls (HC) were included in this study. All subjects were genotyped for the rs1572931 SNP by using polymerase chain reaction and direct sequencing.

Results: Significant differences were observed in the genotype and minor allele frequency (MAF) of rs1572931 between PD and HC (P = 0.0001 and P = 1.08E-04, respectively) and between late-onset PD and matched controls (P = 0.0011 and P = 0.0002, respectively). However, no differences were observed between early-onset PD and HC. The number of minor allele carriers was significantly lower in PD patients than in HC (P = 2.96E-05, odds ratio 0.63, 95% confidence interval 0.51-0.78). No differences were observed between groups with respect to sex, onset symptoms, absence or presence of cognition impairment, anxiety or depression. In addition, no differences were found in the genotype and MAF of rs1572931 between SALS and HC or between MSA and HC.

Conclusion: Our results suggest that rs1572931 decreases the risk for PD but not for ALS and MSA in the Chinese population. However, the polymorphism is unlikely to be a common cause of SALS and MSA in the Chinese population.