Autoimmune Susceptibility (RA or MS) and Your Genetics

Written by Scott Peeples, BS Biomedical Sciences · ExomeDNA Founder Reviewed by ExomeDNA Editorial Process Last reviewed: 2026-05-29

For informational purposes only. Consult a healthcare provider for clinical guidance.

What is autoimmune susceptibility (RA or MS)?

Rheumatoid arthritis (RA) and multiple sclerosis (MS) are two distinct autoimmune conditions that, despite affecting different organ systems, share a common thread: in both, the immune system misdirects its defenses against the body's own healthy tissue. In RA, immune cells attack the synovial lining of joints, driving inflammation, swelling, and over time, structural joint damage. In MS, the immune attack targets myelin — the protective sheath around nerve fibers — disrupting the electrical signals that the nervous system relies on for movement, sensation, and cognition.

These two conditions sit at opposite ends of clinical presentation. RA affects roughly 1% of adults worldwide and causes joint pain, morning stiffness, and in severe cases, significant disability. MS affects approximately 2.9 million people globally, with a particularly high prevalence in Northern European populations, and can follow a relapsing-remitting or progressive course. Despite these clinical differences, geneticists have long noted that RA and MS share overlapping susceptibility loci — regions of the genome where variation influences immune regulation in ways that raise risk for both conditions.

This shared genetic architecture is why genome-wide association studies (GWAS) sometimes analyze RA and MS together, as captured by PMID 37377963. The intersection of susceptibility signals across these conditions offers insights into the underlying biology of autoimmunity more broadly: what makes the immune system lose tolerance for self, and why some individuals are more vulnerable than others.

~1% of adults worldwide live with rheumatoid arthritis, making it one of the most common inflammatory autoimmune conditions.^[1]

The genetics behind autoimmune susceptibility (RA or MS)

The genetic architecture of autoimmune susceptibility is complex, involving hundreds of loci — but a handful of genes and genomic regions carry disproportionate weight. The most prominent is the HLA (human leukocyte antigen) region on chromosome 6, which encodes proteins essential for immune cell recognition of self versus non-self. Variation in HLA genes, particularly HLA-DQB1, HLA-B, and related loci, is among the strongest known contributors to autoimmune risk across many conditions, including both RA and MS.

Beyond the HLA region, several genes emerge from genetic mapping of this trait:

ANKRD55 (chromosome 5, rank 1 by L2G score) encodes ankyrin repeat domain 55, a protein expressed prominently in immune cells. Variation near this gene has been associated with multiple autoimmune phenotypes, and it sits in a genomic neighborhood implicated in immune cell differentiation and inflammatory signaling. Its high L2G confidence score reflects strong genetic evidence linking this locus to autoimmune susceptibility.

PTPN22 (chromosome 1, rank 2) encodes protein tyrosine phosphatase non-receptor type 22, a key regulator of T cell activation thresholds. The PTPN22 R620W variant (rs2476601) is one of the most replicated autoimmune risk variants in human genetics, associated with RA, type 1 diabetes, lupus, and other immune-mediated conditions. It alters the phosphatase activity of PTPN22 in ways that dysregulate T cell signaling.

AGPAT1 encodes an enzyme involved in phospholipid biosynthesis, converting lysophosphatidic acid to phosphatidic acid — lipids involved in cellular signaling cascades. ATF6B functions as a transcription factor in the unfolded protein response (UPR), activated under endoplasmic reticulum stress conditions, which plays a role in immune cell homeostasis. BTNL2, located within the HLA region, encodes a butyrophilin-like molecule involved in T cell costimulation and may serve as a checkpoint in immune activation. COL11A2 encodes a collagen subunit with roles in connective tissue structure, and variants in this region have been associated with autoimmune and inflammatory conditions.

The broader gene panel for this trait — spanning 41 filtered genes total — reflects the polygenic, HLA-centered architecture typical of autoimmune susceptibility traits.

The HLA region on chromosome 6 contains some of the most polymorphic genes in the human genome and accounts for a substantial portion of inherited autoimmune risk across multiple conditions.^[1]

What the research says

The reference study for this trait (PMID 37377963) used a cross-phenotype GWAS design to identify genetic loci shared between RA and MS. This analytical approach — examining both conditions together — increases statistical power to detect loci that individually might not reach genome-wide significance for either condition alone. It is a productive strategy for uncovering the pleiotropic architecture of autoimmunity.

For a deeper discussion of how ExomeDNA interprets multi-trait GWAS results and evaluates genetic association evidence, see our methodology page.

The broader literature on RA and MS genetics is extensive. For RA, GWAS have implicated more than 100 loci, with strong signals in HLA-DRB1, PTPN22, STAT4, CTLA4, and TRAF1. For MS, the genetic architecture is similarly polygenic, with the HLA-DRB1*15:01 haplotype representing the single largest genetic risk factor identified to date. The cross-trait nature of loci like ANKRD55 and PTPN22 underscores that autoimmune diseases share common pathways even when clinical manifestations differ.

This moderate-confidence trait reflects one primary GWAS study in the reference set. As cross-phenotype analyses and multi-ancestry studies accumulate, the picture of shared autoimmune genetics will continue to evolve.

How autoimmune susceptibility (RA or MS) affects you

For anyone with a family history of autoimmune conditions, or who has experienced unexplained joint inflammation, fatigue, or neurological symptoms, understanding the genetic landscape of RA and MS can provide useful context. Genetic susceptibility variants do not operate deterministically — they shift probabilities within a broader equation that includes environmental factors, infections, hormonal influences, and lifestyle.

RA typically presents in midlife, though it can occur at any age. Early signs include morning joint stiffness lasting more than an hour, symmetric joint swelling (often hands and wrists), and fatigue. MS symptoms depend on which neural pathways are affected and may include visual disturbances, limb weakness, sensory changes, or cognitive shifts. Both conditions benefit significantly from early intervention: in RA, disease-modifying drugs (DMARDs) and biologics can slow or halt structural damage when started early; in MS, disease-modifying therapies reduce relapse frequency and delay progression.

For individuals with elevated genetic susceptibility signals, the practical implication is heightened awareness. Autoimmune conditions can be manageable with appropriate medical care, and early detection through symptom recognition and timely clinical assessment leads to better long-term outcomes. People with a family history of autoimmune disease — regardless of their own genetic result — are generally advised to discuss screening approaches with their healthcare provider.

Environmental factors interact meaningfully with autoimmune genetics. Smoking, for instance, is a well-established environmental risk factor for RA, particularly in carriers of the HLA-DRB1 shared epitope. Vitamin D levels, gut microbiome composition, and prior infections (including Epstein-Barr virus for MS) are all areas of active research.

Working with your profile

A genetic result in this category reflects your inherited pattern of variation across the susceptibility loci associated with RA and MS in population studies. It does not constitute a clinical assessment of your personal immune status or joint health.

For anyone reviewing this result, a few practical points:

First, polygenic autoimmune risk is population-level signal, not individual forecasting. The variants captured here shift group-level odds; they do not translate directly into a personal probability statement for any individual. Environmental exposures, lifestyle patterns, and random biological noise all shape whether and when autoimmune conditions manifest.

Second, For anyone experiencing persistent joint swelling, unexplained fatigue, neurological symptoms, or a history of inflammatory episodes — discussing these with a rheumatologist or neurologist who can evaluate clinically is the right step. Genetic data is complementary to clinical assessment, not a substitute.

Third, modifiable factors matter. Avoiding smoking, maintaining healthy vitamin D levels, managing chronic stress, and supporting gut health through diet and exercise are all areas where evidence suggests benefit for immune regulation, even if the mechanisms are not fully elucidated.

Finally, this result captures a snapshot of current genetic knowledge. The science of autoimmune genetics is active and evolving; future research may identify additional loci, refine risk estimates, or reveal gene-environment interactions not yet fully characterized.

Autoimmune susceptibility is part of a broader family of immune-mediated conditions that share genetic architecture. Related traits on ExomeDNA include lupus susceptibility, type 1 diabetes risk, psoriasis and psoriatic arthritis, celiac disease, and inflammatory bowel disease — all of which involve overlapping HLA and immune-regulatory gene signals.

Key genes in this trait's neighborhood — PTPN22, ANKRD55, BTNL2, and HLA-DQB1 — appear across multiple autoimmune GWAS, reflecting their central roles in immune tolerance and T cell regulation. PTPN22 in particular is one of the most pleiotropic autoimmune risk genes known, with associations spanning RA, lupus, type 1 diabetes, Graves' disease, and more.

C2 encodes complement component 2, part of the classical complement pathway; complement deficiency has long been associated with lupus-like phenotypes. COL11A2 encodes a collagen chain relevant to connective tissue integrity, linking this genetic region to structural as well as immune phenotypes.

For individuals interested in the broader picture of immune genetic architecture, exploring related autoimmune traits within your ExomeDNA report can help contextualize any single result within the larger pattern of your immune-regulatory genetics.

Frequently asked questions

Q: Does a higher genetic score mean I will get RA or MS? A: No. Genetic susceptibility scores reflect population-level associations; they are not individual forecasts. Many people with elevated scores never develop these conditions, and some who develop RA or MS carry relatively common genetic profiles. The score is one input into a complex picture that includes environment, lifestyle, and chance.

Q: Can I do anything to lower my risk? A: Some environmental risk factors for autoimmune conditions are modifiable. For RA specifically, not smoking is one of the most evidence-supported actions, particularly for carriers of HLA-DRB1 shared epitope variants. Maintaining adequate vitamin D levels, supporting gut microbiome diversity through diet, and managing chronic stress are areas of ongoing research. No single intervention reliably prevents autoimmune disease, but these lifestyle factors broadly support immune health.

Q: Why are RA and MS analyzed together in some studies? A: Both conditions involve immune dysregulation and share overlapping genetic risk loci, particularly in the HLA region. Analyzing them together in cross-phenotype GWAS increases statistical power to detect shared signals that might not reach significance when either condition is studied in isolation. This approach helps identify the pleiotropic genetic architecture of autoimmunity.

Q: Are there genetic tests that can tell me if I have RA or MS? A: Genetic testing alone cannot identify whether someone has RA or MS — clinical identification requires physician evaluation, symptom assessment, laboratory tests (such as rheumatoid factor, anti-CCP antibodies for RA), and in the case of MS, MRI and neurological examination. Genetic results, including those from ExomeDNA, are informational and not a substitute for clinical evaluation.

Q: What are the ANKRD55 and PTPN22 genes, and why do they matter? A: ANKRD55 encodes a protein expressed in immune cells and has been associated with multiple autoimmune traits in GWAS. PTPN22 encodes a phosphatase that regulates T cell activation; a specific variant in this gene (R620W) is one of the most replicated autoimmune risk variants in human genetics, associated with RA, lupus, type 1 diabetes, and other conditions. Both genes illustrate how shared immune regulatory pathways underlie seemingly different autoimmune diseases.

References

PMID 37377963 — Cross-phenotype GWAS of rheumatoid arthritis and multiple sclerosis.

This page is for educational purposes only. ExomeDNA does not provide clinical guidance. For health-related questions, please consult a qualified healthcare provider.

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