The Genetic Basis of Probable REM Sleep Behavior Disorder in Parkinson's Disease

Identifying Key Plasma Proteins in the Onset of Parkinson's Disease: Proteome-Wide Mendelian Randomization and Single-Cell RNA Sequencing Analysis

Currently, the pathogenesis of Parkinson's disease (PD) remains enigmatic, primarily due to the scarcity of definitive diagnostic markers, thereby hampering both diagnosis and treatment. The urgent need for accessible plasma markers and targeted therapeutic agents has prompted us to employ various methodologies. We leveraged Mendelian randomization analysis, colocalization analysis, SMR analysis, and the HEIDI test to delve into the causal relationships between 2923 plasma proteins in the UK Biobank and PD. Our findings revealed that 21 plasma proteins, including CTF1 and STX4, may demonstrate causal relationships with PD. Further single-cell and bioinformatics analyses have shed light on the fact that 18 of these proteins exhibit differential expression across various brain cell types in patients with PD. These proteins are involved in crucial biological processes, including peptide binding, amide binding, amyloid-beta binding, endocytic vesicle formation, and the functioning of early endosomes. Notably, the PPI network exhibited interactions between ITGAM and HLA-DRA, as well as APOE, while APOE displayed interactions with APOA1, and SERPINE2 interacted with VNN2. Furthermore, our study demonstrates that plasma proteins, including CTF1, STX4, HPGDS, and APOA1, exhibit therapeutic potential for drug development based on gene-drug interaction predictions. While these findings provide a theoretical basis for the exploration of diagnostic markers and potential therapeutic targets for PD, extensive experimental validation is essential to confirm their potential in the future.

GBA1 rs3115534 Is Associated with REM Sleep Behavior Disorder in Parkinson's Disease in Nigerians

BACKGROUND

Rapid eye movement (REM) sleep behavior disorder (RBD) is an early feature of Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Damaging coding variants in Glucocerebrosidase (GBA1) are a genetic risk factor for RBD. Recently, a population-specific non-coding risk variant (rs3115534) was found to be associated with PD risk and earlier onset in individuals of African ancestry.

OBJECTIVES

We aimed to investigate whether the GBA1 rs3115534 PD risk variant is associated with RBD in persons with PD.

METHODS

We studied 709 persons with PD and 776 neurologically healthy controls from Nigeria. All DNA samples were genotyped and imputed, and the GBA1 rs3115534 risk variant was extracted. The RBD screening questionnaire (RBDSQ) was used to assess symptoms of possible RBD.

RESULTS

RBD was present in 200 PD (28.2%) and 51 (6.6%) controls. We identified that the non-coding GBA1 rs3115534 risk variant is associated with possible RBD in individuals of Nigerian origin (β, 0.3640; standard error [SE], 0.103, P = 4.093e-04), as well as in all samples after adjusting for PD status (β, 0.2542; SE, 0.108; P = 0.019) suggesting that although non-coding, this variant may have the same downstream consequences as GBA1 coding variants.

CONCLUSIONS

Our results indicate that the non-coding GBA1 rs3115534 risk variant is associated with an increasing number of RBD symptoms in persons with PD of Nigerian origin. Further research is needed to assess if this variant is also associated with polysomnography-defined RBD and with RBD symptoms in DLB. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.