FLG rs61816761: Understanding Filaggrin and Skin Barrier Health
The rs61816761 variant is a loss-of-function mutation in the FLG gene, which provides instructions for making the filaggrin protein. This genetic change is associated with an impaired skin barrier, which can increase the risk of developing atopic dermatitis and certain food allergies, such as peanut allergy.
What each genotype means
Typical filaggrin production
This genotype represents the common, functional version of the FLG gene. Individuals with this profile do not carry this specific loss-of-function mutation and are considered to have the reference sequence at this position.
This is the most common genotype found in the vast majority of the global population.
Increased risk of skin sensitivity
Carrying one copy of this mutation may result in reduced filaggrin protein levels in the skin, which is associated with a higher statistical likelihood of developing atopic dermatitis, eczema, or ichthyosis vulgaris. Research suggests this variant can also influence the age of onset for allergic conditions, though individual outcomes vary significantly based on other genetic and environmental factors.
Carried by roughly 1–3% of people of European ancestry; it is considered rare in East Asian and African populations.
Higher risk of skin barrier impairment
Carrying two copies of this loss-of-function mutation is associated with a more significant reduction or absence of filaggrin protein in the skin. This profile is linked to a higher statistical risk for more severe forms of ichthyosis vulgaris and a greater predisposition to early-onset allergic diseases, including peanut allergy and asthma. Please discuss any concerns regarding skin health or allergy management with a dermatologist or healthcare provider.
This homozygous genotype is rare, occurring in a very small fraction of the population, primarily within European ancestries.
What is the rs61816761 Variant?
The rs61816761 variant, often referred to in scientific literature as R501X, is a specific single-nucleotide polymorphism (SNP) located within the FLG gene on chromosome 1. This variant is classified as a loss-of-function mutation, meaning it alters the genetic code in a way that prevents the body from producing a functional version of the associated protein. Because the FLG gene is essential for the structural integrity of the outermost layer of the skin, changes like rs61816761 can disrupt the skin's ability to act as an effective barrier against the environment. Researchers track this variant because it serves as a significant genetic marker for understanding how skin health influences systemic immune responses, including the development of allergic conditions.
The Role of the FLG Gene
The FLG gene encodes a protein called profilaggrin, which is processed into filaggrin within the epidermis. Filaggrin acts as a critical 'filament-aggregating protein' that helps bundle keratin fibers, leading to the formation of a strong, protective cornified envelope in skin cells. Beyond structural support, the breakdown products of filaggrin are vital for maintaining the skin's natural moisture levels and acidic pH. When the FLG gene contains a loss-of-function mutation, the skin barrier becomes porous and less effective at retaining water or blocking external irritants. This structural weakness allows allergens, bacteria, and other environmental triggers to penetrate the skin more easily, which can trigger inflammatory immune responses and contribute to the development of atopic diseases.
Research and Clinical Associations
Scientific research has consistently identified a strong association between FLG loss-of-function variants and atopic dermatitis, a chronic inflammatory skin condition. Furthermore, studies have linked these mutations to an increased risk of IgE-mediated peanut allergy. The theory is that an impaired skin barrier allows peanut proteins to enter the body through the skin rather than the gut, leading to early-onset sensitization. While the statistical association between rs61816761 and these conditions is well-documented in many studies, the evidence strength is sometimes described as limited in specific contexts due to high heterogeneity across different ethnic populations. It is important to note that having this variant does not guarantee the development of an allergy or skin condition; rather, it is one of many genetic and environmental factors that contribute to an individual's overall risk profile.
Population Frequency
The frequency of the rs61816761 variant varies significantly across different ancestral groups. It is most commonly observed in populations of European descent, where carrier frequencies typically range from 1% to 3%. In contrast, this specific variant is considered rare in populations of East Asian or African ancestry. Because genetic studies have historically focused heavily on European cohorts, our understanding of how this variant impacts health in other populations is still evolving. As more diverse genomic data becomes available, researchers are better able to determine the prevalence and clinical impact of this variant across the global population, highlighting the importance of considering ancestry when interpreting genetic information.
Interpreting Your Genetic Information
Understanding your genetic variants can provide insight into your biological predispositions, but it is not a substitute for professional medical advice. If you are concerned about skin health, atopic dermatitis, or food allergies, you should consult with a dermatologist, allergist, or primary care physician. These professionals can evaluate your symptoms, medical history, and environmental factors to provide an accurate diagnosis and personalized management plan. You cannot use this information to diagnose yourself or to predict with certainty whether you will develop a specific condition. Always discuss any health concerns or potential changes to your lifestyle or medical care with a qualified clinician who can interpret your results within the context of your overall health.
How common is this variant?
The rs61816761 variant has a carrier frequency of approximately 1–3% in European populations and is considered rare in East Asian and African ancestries.
Frequently asked questions
Does having the rs61816761 variant mean I will have a peanut allergy?
No. While this variant is associated with an increased risk of peanut allergy, it is not a direct cause. Many people with this variant do not develop allergies, and many people with peanut allergies do not carry this specific mutation.
Can I fix my skin barrier if I have this variant?
While you cannot change your genetics, you can support your skin barrier. Dermatologists often recommend using fragrance-free moisturizers and gentle cleansers to help maintain skin hydration and integrity.
Is this variant the same as R501X?
Yes, rs61816761 is the rsID for the mutation commonly referred to as R501X in scientific literature. Both terms refer to the same specific change in the FLG gene.
Should I get tested for this variant?
Genetic testing for this variant is generally not recommended for the general public. If you have concerns about allergies or skin conditions, it is best to speak with a doctor who can assess your clinical symptoms.
Sources & further reading
Educational information only, last refreshed 10/17/2026. 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.
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.
Skin barrier filaggrin risk-associated variant commonly implicated in the atopic march from severe infant atopic dermatitis to secondary food sensitization.