# Carriers of Parkinson’s disease-linked SNCA Rep1 variant have greater non-motor decline: a 4 year follow up study

## TL;DR

This study shows that people with a specific genetic variant linked to Parkinson's disease experience faster non-motor symptom decline over four years.

## Contribution

The first longitudinal study to link SNCA Rep1 allele length with non-motor symptom progression in Parkinson's disease.

## Key findings

- Long Rep1 carriers showed faster global cognition decline (p = 0.023).
- Greater apathy and attention/memory decline were observed in long Rep1 carriers (p = 0.027 and p = 0.001).
- Rep1 polymorphism can help identify patients at higher risk for non-motor symptom decline.

## Abstract

Alpha-synuclein gene promoter (SNCA Rep1) polymorphism has been linked to Parkinson's Disease (PD) susceptibility and motor symptom severity, but less is known about its longitudinal relationship with non-motor symptom severity. To address this gap, this is the first longitudinal study over 4 years investigating the relationship between Rep1 allele length and non-motor function amongst 208 early PD patients grouped into long (n = 111) vs. short (n = 97) Rep1 allele carriers. Long Rep1 carriers demonstrated faster decline in global cognition (p = 0.023) and increasing apathy (p = 0.027), with greater decline in attention and memory domains (p = 0.001), highlighting the utility of Rep1 polymorphism in stratifying patients at risk of non-motor symptom decline.