FLG rs1140343: Understanding Skin Barrier Genetics
The rs1140343 variant is a common genetic polymorphism located within the FLG gene, which provides instructions for making the protein filaggrin. This variant is studied for its potential role in skin barrier integrity and its association with conditions like atopic dermatitis and allergic rhinitis.
What each genotype means
Typical skin barrier profile
This genotype represents the most common form of the FLG gene in many populations. It is not associated with the specific filaggrin-related skin barrier disruptions or increased risk for atopic conditions linked to the variant. You do not carry the variant allele associated with these traits.
This is the most common genotype globally, found in the majority of the population.
Increased skin barrier sensitivity
Carrying one copy of this variant may be associated with a slightly higher susceptibility to skin barrier impairment. Research suggests that individuals with this genotype may have a higher statistical likelihood of developing atopic dermatitis or related allergic conditions compared to those without the variant. Please consult with a dermatologist or healthcare provider regarding any concerns about skin health or allergic symptoms.
This heterozygous genotype is common, appearing in a significant portion of the population depending on ancestral background.
Elevated skin barrier risk
Carrying two copies of this variant is associated with a higher statistical risk for filaggrin-related skin barrier disruption. This may manifest as increased susceptibility to dry skin, atopic eczema, or secondary allergic conditions like allergic rhinitis. These associations are based on population studies; please discuss your skin health and any allergic history with a clinician for personalized guidance.
This homozygous genotype is less common than the heterozygous form but is observed across various global populations.
What is rs1140343 and Where is it Located?
The rs1140343 variant is a single-nucleotide polymorphism (SNP) situated within the FLG gene. In genomics, a SNP represents a variation at a single position in the DNA sequence among individuals. The FLG gene is located on chromosome 1 and is responsible for encoding filaggrin, a structural protein that plays a critical role in the formation and maintenance of the skin barrier. Because the skin acts as the body's primary defense against environmental pathogens and allergens, variations in genes that support this barrier are of significant interest to researchers. While many variants in the FLG gene are classified as loss-of-function mutations that directly disrupt protein production, rs1140343 is a common polymorphism that is frequently analyzed in the context of skin health and immune-related traits.
The Role of the FLG Gene
The FLG gene encodes filaggrin, a protein essential for the development of the cornified envelope in the outermost layer of the skin, known as the stratum corneum. Filaggrin helps aggregate keratin filaments, which provides structural support to skin cells. Furthermore, as filaggrin breaks down, it produces natural moisturizing factors that help maintain skin hydration and regulate the skin's pH levels. When the FLG gene is altered, the resulting protein may be nonfunctional or produced in insufficient quantities, leading to a compromised skin barrier. A weakened barrier can allow moisture to escape and allergens or irritants to enter, which is a hallmark of conditions like atopic dermatitis. Understanding how specific variants like rs1140343 influence this process is a major focus of dermatological and immunological research.
Research Associations and Evidence Strength
Research into the FLG gene has established a strong link between loss-of-function mutations and an increased risk of atopic dermatitis, asthma, and allergic rhinitis. However, the evidence for rs1140343 specifically is considered limited compared to well-characterized pathogenic mutations. While some studies investigate this variant as part of broader genetic panels related to skin barrier disruption, it does not always show the same high-effect size as rare, severe loss-of-function mutations. Associations between common polymorphisms and complex traits are often influenced by environmental factors and the overall genetic background of the individual. Because of this, the clinical significance of rs1140343 remains a subject of ongoing investigation. It is important to note that genetic associations are statistical in nature and do not imply a direct cause-and-effect relationship for every individual.
Population Frequency
The rs1140343 variant is a common polymorphism found across diverse global populations. According to data from the Genome Aggregation Database (gnomAD), this variant typically exhibits a minor allele frequency (MAF) ranging from approximately 0.20 to 0.35. This high frequency indicates that a significant portion of the global population carries at least one copy of the variant allele. Because it is so common, it is considered a standard part of human genetic variation rather than a rare mutation. Researchers often use this frequency data to compare different ethnic groups, noting that while the variant is widespread, its specific impact on health outcomes can vary significantly depending on the population's unique genetic and environmental context.
What You Can and Cannot Do With This Information
Genetic information regarding variants like rs1140343 is intended for educational and research purposes only. It is not a diagnostic tool and cannot predict whether an individual will develop a specific skin condition or allergy. Many factors, including diet, environment, and other genetic markers, contribute to the development of complex traits. If you are concerned about skin health, allergies, or persistent dermatitis, you should consult a board-certified dermatologist or an allergist. These professionals can provide a clinical evaluation based on your symptoms and medical history. Never use genetic data to make decisions about medical treatments or to self-diagnose. If you are interested in how your genetic profile might relate to your health, discuss these findings with a healthcare provider or a genetic counselor who can help interpret the results within the context of your overall health.
How common is this variant?
The rs1140343 variant is a common polymorphism with a global minor allele frequency typically ranging between 0.20 and 0.35 in gnomAD.
Frequently asked questions
Is rs1140343 a cause of eczema?
No, rs1140343 is not a direct cause of eczema. While some FLG variants are associated with an increased risk of atopic dermatitis, this specific variant is a common polymorphism and does not guarantee the development of any skin condition.
Should I get tested for FLG variants?
Genetic testing for FLG variants is generally not recommended for the general public. If you have concerns about skin conditions or allergies, a clinical evaluation by a dermatologist is the most appropriate step.
Does this variant affect how I should treat my skin?
No, this variant does not dictate specific skin care treatments. You should follow the advice of a healthcare professional regarding any skin care regimen or treatment for dermatological conditions.
Are there other genes involved in skin barrier health?
Yes, skin barrier health is a complex trait influenced by many genes, not just FLG. Other genes involved in lipid metabolism, immune response, and structural integrity also play significant roles.
Sources & further reading
Educational information only, last refreshed 10/17/2026. Not medical advice — these associations describe population statistics, not individual predictions.
Curious what your genotype is for rs1140343?
Upload a raw DNA file from 23andMe, AncestryDNA, MyHeritage, or FamilyTreeDNA and see this variant — plus thousands more — interpreted in your full report.
Get my report — $29Related variants in FLG
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.
A filaggrin locus variant associated with impaired epidermal barrier function, predisposing to atopic dermatitis and allergic sensitization.
Skin barrier filaggrin risk-associated variant commonly implicated in the atopic march from severe infant atopic dermatitis to secondary food sensitization.