FLG rs1113589: Skin Barrier Function and Genetics
The rs1113589 variant is a single-nucleotide polymorphism located within the filaggrin (FLG) gene on chromosome 1q21. The FLG gene encodes a key structural protein vital for maintaining an intact epidermal barrier and preventing transepidermal water loss. In research cohorts, rs1113589 has been investigated for its potential role in epidermal barrier integrity and downstream epicutaneous allergen sensitization, though overall evidence remains limited.
What each genotype means
Typical skin barrier function
You carry two copies of the common A allele for this filaggrin variant. Research indicates this genotype is not linked to altered filaggrin integrity or increased vulnerability to skin barrier disruption. Your baseline genetic profile at this locus reflects standard population risk for epidermal barrier sensitivity.
Carried by approximately 84% to 86% of individuals of European ancestry and is the predominant genotype across global populations.
Mildly altered skin barrier
You carry one copy of the G alternate allele in the FLG gene. Preliminary research suggests this missense variation may mildly alter skin barrier function or elevate susceptibility to epicutaneous allergen sensitization, though overall clinical evidence remains limited. This genotype does not cause severe skin conditions on its own and represents a modest statistical tendency rather than a diagnosis.
Found in about 14% to 15% of European populations, with considerably lower prevalence documented in African and East Asian ancestries.
Reduced epidermal barrier integrity
You carry two copies of the less common G allele at this filaggrin site. Having two copies is hypothesized in limited studies to contribute to subtle stratum corneum barrier compromise and potential allergen permeability, although evidence specific to this missense variant is limited and not classified as high-penetrance loss of function. It does not mandate the development of atopic conditions or eczema.
Relatively uncommon, occurring in fewer than 1% of individuals across European and most global populations.
Genomic Location and Variant Characteristics
The single-nucleotide polymorphism rs1113589 is situated in the filaggrin (FLG) gene, localized within the epidermal differentiation complex on chromosome 1q21. This genomic region harbors a cluster of genes critical for epidermal maturation and structural integrity. The rs1113589 variant is a missense substitution that alters the nucleotide sequence within the FLG coding region. Because FLG contains large repetitive segments and exhibits substantial genetic diversity across populations, missense and non-synonymous variants are tracked in genomic repositories like dbSNP and Ensembl to determine whether they alter amino acid sequences or affect post-translational processing. Unlike severe null alleles that truncate the protein, missense single-nucleotide changes like rs1113589 represent subtle variations whose structural impacts are continuously being characterized.
The Biological Role of the Filaggrin Gene
The FLG gene provides instructions for producing profilaggrin, a large, insoluble polyprotein precursor concentrated within keratohyalin granules in the epidermis. During the terminal differentiation of keratinocytes, profilaggrin is proteolytically cleaved into multiple active filaggrin peptides. These filaggrin molecules bind and aggregate keratin intermediate filaments, collapsing them into dense bundles that form the robust structural scaffold of the stratum corneum—the outermost layer of the skin. As these cells mature, filaggrin is further degraded into free amino acids and hygroscopic derivatives that constitute natural moisturizing factor (NMF). NMF is essential for maintaining epidermal hydration, regulating skin surface pH, and supporting antimicrobial defenses against environmental pathogens and allergens.
Epidermal Barrier Integrity and Allergen Sensitization
When filaggrin synthesis or processing is altered, the mechanical barrier of the stratum corneum can become compromised. A weakened barrier permits increased transepidermal water loss, causing dry skin, while simultaneously facilitating the penetration of environmental allergens, irritants, and microbes across the epidermis. This epicutaneous exposure can stimulate immune cells in the dermis and prompt immunoglobulin E (IgE) sensitization, a foundational mechanism in atopic conditions such as atopic dermatitis (eczema), allergic rhinitis, and asthma. While high-impact FLG loss-of-function null mutations (such as p.R501X and c.2282del4) have strong, well-replicated links to barrier defects and eczema, the evidence supporting a direct causal role for rs1113589 is classified as limited. Studies evaluating this variant typically view it as an exploratory marker or a modest genetic modifier rather than a primary driver of disease.
Population Distribution and Frequency
According to large-scale genomic reference resources such as gnomAD and dbSNP, the minor allele frequency (MAF) of rs1113589 varies substantially across ancestral groups. In populations of European descent, the minor allele frequency is approximately 0.08, indicating that around 8% of chromosomes carry the variant allele. Frequencies may differ or appear lower in other continental populations, including African and East Asian cohorts, where distinct spectrums of FLG variation predominate. These population-level differences underscore that genetic variation within FLG is diverse, and the functional relevance of any single variant must be interpreted within the context of an individual's broader genetic ancestry and background haplotypes.
Interpretation and Clinical Perspective
Genomic test results indicating the presence of rs1113589 cannot diagnose any dermatological condition, nor do they guarantee that barrier compromise or allergic sensitization will occur. Most common dermatological and atopic conditions are complex and multifactorial, arising from interactions among dozens of genetic loci, immune responses, and environmental exposures such as climate, hygiene practices, and allergen load. Individuals curious about their skin health should avoid drawing definitive medical conclusions from direct-to-consumer genotyping of exploratory variants. Anyone experiencing persistent dry skin, eczema flares, or symptoms of allergic sensitization should seek evaluation from a qualified dermatologist, allergist, or healthcare provider for evidence-based clinical care.
How common is this variant?
The minor allele frequency for rs1113589 is approximately 0.08 in populations of European ancestry, with varying frequencies across other global reference populations in genomic databases like gnomAD.
Frequently asked questions
What is the FLG rs1113589 variant?
The rs1113589 variant is a single-nucleotide polymorphism found in the filaggrin (FLG) gene on chromosome 1. It represents a small sequence alteration in a gene that produces a key protein responsible for the structure and hydration of the skin's outer barrier.
Does carrying rs1113589 mean I will develop eczema or skin allergies?
No. The scientific evidence linking rs1113589 directly to atopic dermatitis or allergies is limited, and carrying this variant does not cause disease on its own. Atopic conditions are complex traits influenced by many genes, the immune system, and daily environmental exposures.
How does filaggrin affect the skin barrier?
Filaggrin helps bind keratin filaments together to create a sturdy structural wall in the outer epidermis and breaks down into natural moisturizing factor (NMF) to retain hydration. When filaggrin function is significantly disrupted, the skin loses moisture more quickly and becomes more permeable to environmental allergens.
What should I do if my genetic data shows this variant?
Genetic test results for rs1113589 are educational and exploratory rather than diagnostic. If you have concerns about chronic dry skin, rashes, or allergic reactions, you should consult a dermatologist or healthcare provider who can evaluate your symptoms and recommend appropriate skincare or treatments.
Sources & further reading
Educational information only, last refreshed 9/12/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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A well-characterized loss-of-function null mutation (2282del4) in filaggrin predisposing individuals to cutaneous allergen penetration and the atopic march.
Loss-of-function variant (p.Lys501Ter) in FLG, a major predisposing factor for atopic dermatitis and ichthyosis vulgaris.
Filaggrin missense and splice-region variant associated with skin barrier disruption, atopic dermatitis, and allergic sensitization.
Loss-of-function mutation 2282del4 in filaggrin predisposing to peanut allergy.
Filaggrin coding variant associated with skin barrier disruption and allergic conditions.
A filaggrin locus variant associated with impaired epidermal barrier function, predisposing to atopic dermatitis and allergic sensitization.