MHC rs114771815: Genetic Association and Myositis Risk
The genetic variant rs114771815 is a single nucleotide polymorphism located within the major histocompatibility complex (MHC) region on chromosome 6. Published genome-wide association studies link this ancestral variant to susceptibility to idiopathic inflammatory myopathies, including dermatomyositis and polymyositis. Possessing the variant allele contributes modest statistical risk rather than directly causing inflammatory autoimmune muscle disease.
What each genotype means
Typical inflammatory risk profile
Your genotype carries two copies of the standard common C allele at this MHC locus. In genetic association studies, this genotype is not linked to elevated susceptibility to idiopathic inflammatory myopathies. It reflects the baseline population risk profile observed for this genomic marker.
Carried by approximately 80% to 90% of individuals of European ancestry and is the predominant genotype across most global populations.
Moderately altered myopathy risk
You carry one copy of the ancestral minor T allele associated with altered immune regulation within the major histocompatibility complex (MHC). Statistical studies indicate that carrying this allele is associated with an increased susceptibility to idiopathic inflammatory myopathies, including dermatomyositis and polymyositis. Because complex autoimmune conditions are polygenic and influenced by environmental triggers, having this variant does not indicate a diagnosis.
Carried by roughly 10% to 18% of people of European descent; it occurs at markedly lower frequencies in East Asian and African ancestries.
Elevated myopathy risk profile
You carry two copies of the minor T allele in the MHC region associated with idiopathic inflammatory myopathies. In cohort studies, carrying two risk alleles confers a stronger statistical correlation with autoimmune inflammatory myopathies compared to carrying one or none. However, many individuals with this genotype never develop an inflammatory muscle disorder, as overall risk depends on multiple genetic and environmental factors.
Found in less than 1% of individuals across most ancestries, occurring in approximately 0.5% to 1% of individuals of European descent.
Understanding rs114771815 and the MHC Region
The single nucleotide polymorphism rs114771815 is mapped to the human major histocompatibility complex (MHC) locus on the short arm of chromosome 6 (6p21.3). The MHC region is one of the most genetically dense, polymorphic, and immunologically critical areas of the human genome. It contains hundreds of genes, most notably human leukocyte antigen (HLA) genes that dictate self versus non-self antigen recognition by the adaptive immune system. Because the MHC displays extensive linkage disequilibrium, variants like rs114771815 are frequently inherited alongside specific ancestral haplotypes, such as the 8.1 ancestral haplotype (AH8.1). This high level of co-inheritance means that variations in this region often track together across generations, reflecting ancient evolutionary combinations of immune-regulatory sequences.
Biological Role and Immune Regulation
The MHC region plays an indispensable role in adaptive immune defenses, presenting peptide fragments to T cells to initiate targeted immune responses against pathogens while maintaining tolerance to healthy body tissues. While rs114771815 does not necessarily cause an amino acid substitution in a single coding protein, it acts as a molecular marker or regulatory variant within this vast immunological cluster. Alterations in MHC sequence structure can influence gene expression levels, antigen-binding pocket geometries, and the stability of antigen presentation complexes. In autoimmune contexts, atypical presentation of endogenous muscular proteins or aberrant inflammatory cytokine signaling can prompt self-reactive immune pathways, ultimately predisposing an individual to immune-mediated muscle tissue inflammation.
Evidence for Association with Inflammatory Myopathies
Idiopathic inflammatory myopathies (IIM) comprise a rare and heterogeneous group of systemic autoimmune connective tissue diseases, including adult dermatomyositis, juvenile dermatomyositis, and polymyositis. In large-scale genome-wide association studies across European-descent cohorts, rs114771815 was identified with genome-wide significance (P = 9.0 × 10⁻¹¹, odds ratio ~1.70) as an independent residual risk signal within the MHC. Although core HLA alleles such as HLA-DRB1*03:01 explain the vast majority of myositis susceptibility, fine-mapping reveals that markers like rs114771815 capture distinct, persistent statistical signals. Current scientific consensus rates the evidence strength for this association as moderate, reflecting robust statistical reproducibility in European cohorts alongside a need for further functional validation across diverse global populations.
Interpreting Genetic Associations in Daily Life
Finding rs114771815 in your genetic data is not a medical diagnosis and cannot predict whether you will develop an inflammatory muscle disease. Idiopathic inflammatory myopathies are exceptionally rare conditions, with annual incidence rates of only a few cases per million individuals. Because the baseline population risk is very low, an odds ratio of approximately 1.70 only shifts an individual's absolute probability of developing the disease by a fraction of a percent. This variant functions as a single contributing factor within a complex, multifactorial model involving hundreds of genetic loci and non-genetic environmental triggers. Commercial testing results for this marker should never be used to initiate medical treatments or guide therapeutic decisions without professional clinical consultation.
How common is this variant?
The minor allele associated with rs114771815 has an estimated frequency of approximately 0.05 to 0.10 (5-10%) in populations of European ancestry. It is significantly less common or absent in several non-European ancestral groups.
Frequently asked questions
What is the rs114771815 genetic variant?
The rs114771815 variant is a single nucleotide polymorphism located in the human major histocompatibility complex (MHC) on chromosome 6. It serves as a genetic marker correlated with immune system regulation and autoimmune traits.
Does carrying rs114771815 mean I will get myositis?
No, carrying this variant does not mean you will develop myositis. Idiopathic inflammatory myopathies are rare diseases, and the variant confers only a modest statistical association rather than deterministic causation.
Why is the MHC region linked to autoimmune diseases?
The MHC region encodes human leukocyte antigen (HLA) molecules that train the immune system to distinguish between healthy self-tissues and foreign pathogens. Variations in this region can alter antigen presentation, making self-directed autoimmune responses more likely to occur.
Can lifestyle or diet reduce risks associated with this variant?
There are currently no proven specific dietary or lifestyle interventions that alter the biological effects of rs114771815. General healthy habits supporting immune regulation and regular medical checkups remain the standard recommendation.
What should I do if my genetic test shows this variant?
If you have questions about your personal health, family history of autoimmune diseases, or unusual symptoms such as progressive muscle weakness, you should consult a physician or genetic counselor for comprehensive evaluation.
Sources & further reading
Educational information only, last refreshed 9/9/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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