Genetic Contribution to Medium-Term Disease Activity in Multiple Sclerosis.

Area of Science:

• Genetics
• Neuroimmunology
• Systems Biology

Background:

• Multiple sclerosis (MS) exhibits significant heterogeneity in clinical presentation, prognosis, and treatment response.
• Understanding the genetic underpinnings of MS disease activity is crucial for developing targeted therapies.

Purpose of the Study:

• To investigate the genetic contribution to MS disease activity at the gene, pathway, and tissue-specific network levels.
• To identify genetic variants and genes associated with disease activity over a 4-year follow-up period in relapsing-remitting MS patients.

Main Methods:

• Analysis of two cohorts (n=1294) of relapsing-remitting MS patients initiating first-line treatment.
• Whole-genome single nucleotide polymorphism (SNP) and gene-level association studies.
• Construction and analysis of brain and lymphocyte-specific gene-gene interaction networks.

Main Results:

• Identified 23 variants and 223 genes associated with 4-year MS disease activity.
• Highlighted genes such as PON2 (oxidative stress, mitochondrial function) and ILRUN (immune modulation).
• Discovered distinct brain (228 genes) and lymphocyte (287 genes) network modules, with MPHOSPH9 and OPA1 identified as key players.

Conclusions:

• Genetic factors contribute significantly to MS disease activity.
• Network analyses revealed shared and tissue-specific inflammatory pathways in both brain and lymphocyte modules.
• These findings suggest that common biological mechanisms across different tissues drive MS disease activity.