AUTHOR=Campêlo Clarissa L.C , Cagni Fernanda C. , de Siqueira Figueredo Diego , Oliveira Jr. Luiz G. , Silva-Neto Antônio B. , Macêdo Priscila T. , Santos José R. , Izídio Geison S. , Ribeiro Alessandra M. , de Andrade Tiago G. , de Oliveira Godeiro Clécio , Silva Regina H. TITLE=Variants in SNCA Gene Are Associated with Parkinson’s Disease Risk and Cognitive Symptoms in a Brazilian Sample JOURNAL=Frontiers in Aging Neuroscience VOLUME=9 YEAR=2017 URL=https://www.frontiersin.org/journals/aging-neuroscience/articles/10.3389/fnagi.2017.00198 DOI=10.3389/fnagi.2017.00198 ISSN=1663-4365 ABSTRACT=

Genetic susceptibility contributes to the etiology of sporadic Parkinson’s Disease (PD) and worldwide studies have found positive associations of polymorphisms in the alpha-synuclein gene (SNCA) with the risk for PD. However, little is known about the influence of variants of SNCA in individual traits or phenotypical aspects of PD. Further, there is a lack of studies with Latin-American samples. We evaluated the association between SNCA single nucleotide polymorphisms (single nucleotide polymorphisms, SNPs – rs2583988, rs356219, rs2736990, and rs11931074) and PD risk in a Brazilians sample. In addition, we investigated their potential interactions with environmental factors and specific clinical outcomes (motor and cognitive impairments, depression, and anxiety). A total of 105 PD patients and 101 controls participated in the study. Single locus analysis showed that the risk allele of all SNPs were more frequent in PD patients (p < 0.05), and the associations of SNPs rs2583988, rs356219, and rs2736990 with increased PD risk were confirmed. Further, the G-rs356219 and C-rs2736990 alleles were associated with early onset PD. T-rs2583988, G-rs356219 and C-2736990 alleles were significantly more frequent in PD patients with cognitive impairments than controls in this condition. In addition, in a logistic regression model, we found an association of cognitive impairment with PD, and the practice of cognitive activity and smoking habits had a protective effect. This study shows for the first time an association of SNCA polymorphism and PD in a South-American sample. In addition, we found an interaction between SNP rs356219 and a specific clinical outcome, i.e., the increased risk for cognitive impairment in PD patients.