Gut microbiota and autoimmune neurologic disorders: a two-sample bidirectional Mendelian randomization study.

Area of Science:

• Microbiome research
• Neuroimmunology
• Genetics

Background:

• Growing evidence links gut microbiome changes to autoimmune neurologic disorders.
• A definitive causal relationship between gut microbiota and these conditions remains unestablished.

Purpose of the Study:

• To investigate the causal relationship between gut microbiota composition and three autoimmune neurologic disorders: Multiple Sclerosis (MS), Guillain-Barré Syndrome (GBS), and Myasthenia Gravis (MG).

Main Methods:

• Utilized two-sample Mendelian Randomization (MR) with genome-wide association study (GWAS) summary statistics for gut microbiota and the specified neurologic disorders.
• Performed sensitivity analyses to validate results and reverse causality analysis to confirm the direction of the relationship.

Main Results:

• Specific gut bacteria genera (e.g., *Ruminococcus2*, *Roseburia*) were associated with increased MS risk.
• Increased abundance of *Mollicutes*, *Eubacterium (hallii group)*, and *Tenericutes* correlated with higher GBS probability.
• Several genera (*Ruminococcaceae UCG005*, *Holdemania*, *Lachnoclostridium*, *Eubacterium (ruminantium group)*) were linked to a greater chance of MG occurrence.
• Sensitivity and reverse causality analyses supported the identified causal links.

Conclusions:

• Established a causal link between gut microbiota and autoimmune neurologic disorders (MS, GBS, MG).
• Findings provide novel insights into microbiota-mediated mechanisms underlying these complex neurological conditions.