Abstract
REM sleep behavior disorder (RBD), is a prodromal synucleinopathy affecting a subset of Parkinson's disease (PD) patients and associated with neuropsychiatric symptoms. This study compared the genetic profiles of 13,020 PD patients with probable RBD (PD + RBD) and 5403 without (PD-RBD) using genome-wide association study (GWAS). RBD was assessed by questionnaires or self-reporting. Potential genetic correlations between neuropsychiatric traits and PD + RBD were assessed using linkage disequilibrium score regression. The top variant in the SNCA locus was associated with PD + RBD (rs10005233-T, OR = 1.21, 95% CI = 1.16-1.27, p = 1.81e-15). PD risk variants in SNCA (rs5019538-G, OR = 0.85, 95% CI = 0.81-0.89, p = 2.46e-10; rs356182-G, OR = 0.89, 95% CI = 0.84-0.95, p = 0.0001) and LRRK2 loci (rs34637584, OR = 0.41, 95% CI = 0.28-0.61, p = 1.04e-5) were associated with reduced PD + RBD risk. A suggestive genetic correlation between attention deficit hyperactivity disorder and PD + RBD was observed but was not statistically significant after correction. These findings highlight genetic distinctions between PD + RBD and PD-RBD, offering insights into PD stratification and potential subtype-specific treatments.