# Novel Variants Linked to the Prodromal Stage of Parkinson’s Disease (PD) Patients

## TL;DR

This study identifies new genetic variants linked to early Parkinson’s disease, offering potential biomarkers for early diagnosis before symptoms appear.

## Contribution

The study detects novel genetic variants and loci in the prodromal stage of Parkinson’s disease, providing new biomarkers for early diagnosis.

## Key findings

- Novel variant percentages were detected in prodromal subgroups, ranging from 0.3% to 1.2%.
- Twelve potentially novel loci were identified in the prodromal stage of PD, including MTF2, PIK3CA, and others.
- Genetic biomarkers could enable early diagnosis of Parkinson’s disease without relying solely on phenotypic traits.

## Abstract

Background and objective: The symptoms of most neurodegenerative diseases, including Parkinson’s disease (PD), usually do not occur until substantial neuronal loss occurs. This makes the process of early diagnosis very challenging. Hence, this research used variant call format (VCF) analysis to detect variants and novel genes that could be used as prognostic indicators in the early diagnosis of prodromal PD. Materials and Methods: Data were obtained from the Parkinson’s Progression Markers Initiative (PPMI), and we analyzed prodromal patients with gVCF data collected in the 2021 cohort. A total of 304 participants were included, including 100 healthy controls, 146 prodromal genetic individuals, 21 prodromal hyposmia individuals, and 37 prodromal individuals with RBD. A pipeline was developed to process the samples from gVCF to reach variant annotation and pathway and disease association analysis. Results: Novel variant percentages were detected in the analyzed prodromal subgroups. The prodromal subgroup analysis revealed novel variations of 1.0%, 1.2%, 0.6%, 0.3%, 0.5%, and 0.4% for the genetic male, genetic female, hyposmia male, hyposmia female, RBD male, and RBD female groups, respectively. Interestingly, 12 potentially novel loci (MTF2, PIK3CA, ADD1, SYBU, IRS2, USP8, PIGL, FASN, MYLK2, USP25, EP300, and PPP6R2) that were recently detected in PD patients were detected in the prodromal stage of PD. Conclusions: Genetic biomarkers are crucial for the early detection of Parkinson’s disease and its prodromal stage. The novel PD genes detected in prodromal patients could aid in the use of gene biomarkers for early diagnosis of the prodromal stage without relying only on phenotypic traits.