Longitudinal Study of SNCA Rep1 Polymorphism on Executive Function in Early Parkinson’s Disease

Article type: Short Communication

Authors: Tan, Yi Jayne^{a; b} | Saffari, Seyed Ehsan^{a; c} | Zhao, Yi^d | Ng, Ebonne Y.L.^{b; e} | Yong, Alisa C.W.^{a; b} | Ng, Samuel Y.E.^{a; b} | Chia, Nicole S.Y.^{a; b} | Choi, Xinyi^{b; e} | Heng, Dede^{b; e} | Neo, Shermyn^{a; b} | Xu, Zheyu^{a; b} | Tay, Kay Yaw^{a; b} | Au, Wing Lok^{a; b} | Tan, Eng-King^{b; e; f} | Tan, Louis C.S.^{a; b; 1} | Ng, Adeline S.L.^{a; b; f; 1; *}

Affiliations: [a] Department of Neurology, National Neuroscience Institute, Tan Tock Seng Hospital, Singapore | [b] Parkinson’s Disease and Movement Disorders Centre, USA Parkinson Foundation International Center of Excellence, National Neuroscience Institute, Singapore | [c] Center for Quantitative Medicine, Duke-NUS Medical School, National University of Singapore, Singapore | [d] Department of Clinical Translational Research, Singapore General Hospital, Singapore | [e] Department of Neurology, National Neuroscience Institute, Singapore General Hospital, Singapore | [f] Neuroscience and Behavioural Disorders Program, Duke-NUS Medical School, Singapore

Correspondence: [*] Correspondence to: Dr. Adeline S.L. Ng, National Neuroscience Institute, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, 308433, Singapore. Tel.: +65 6357 7171; E-mail: adeline.ng.s.l@singhealth.com.sg.

Note: [1] Joint senior authors.

Abstract: The alpha-synuclein gene promoter (SNCA-Rep1) is associated with Parkinson’s disease (PD), but its relationship with performance across individual cognitive domains in early PD is unknown. This study aims to investigate Rep1 polymorphism and longitudinal change in cognition in early PD. In this longitudinal study, Rep1 allele lengths (“long” and “short”) were determined in 204 early PD patients. All participants underwent annual neuropsychological assessments and followed up for 3 years. Linear-mixed model was performed to investigate the association of Rep1 status and longitudinal change in individual cognitive domains. At 3 years, significant decline in executive function was observed in long Rep1 allele carriers vs short allele carriers, controlling for potential confounders. This is the first longitudinal study demonstrating that long Rep1 allele carriers are at higher risk for executive dysfunction in early PD.

Keywords: Parkinson’s disease, SNCA Rep1 promoter, cognition, genetics

DOI: 10.3233/JPD-213029

Journal: Journal of Parkinson's Disease, vol. 12, no. 3, pp. 865-870, 2022