Shared Genetics of Multiple System Atrophy and Inflammatory Bowel Disease

Area of Science:

• Neurogenetics
• Immunology
• Gastroenterology

Background:

• Multiple system atrophy (MSA) is a rare neurodegenerative disorder characterized by α-synuclein aggregation and neuronal loss.
• Emerging evidence suggests autoimmune mechanisms may contribute to MSA pathogenesis.
• The genetic basis for the potential interaction between MSA and autoimmune diseases remains largely unknown.

Purpose of the Study:

• To investigate the genetic overlap between MSA and seven autoimmune diseases.
• To identify shared genetic loci contributing to both MSA and autoimmune conditions.

Main Methods:

• Utilized genome-wide association study summary statistics for MSA and seven autoimmune diseases.
• Employed cross-trait conjunctional false discovery rate analysis to identify overlapping genetic regions.
• Examined candidate gene expression in transgenic MSA mice and analyzed genetic variability in independent patient cohorts.

Main Results:

• Identified significant polygenic overlap between MSA and inflammatory bowel disease (IBD).
• Discovered three shared genetic loci, including variants near DENND1B, RSP04, and within the C7 gene.
• Found dysregulated C7 gene expression in MSA mouse models and an increased burden of C7 variants in MSA and IBD patient cohorts.

Conclusions:

• Provided evidence for a shared genetic etiology between MSA and IBD.
• Highlighted the C7 gene as a key player in both MSA and IBD.
• Suggested that immune and gut dysfunction are implicated in the pathophysiology of MSA.