FLG rs11603634: What Your Genotype Means
The single-nucleotide polymorphism rs11603634 is located in the filaggrin (FLG) gene locus on chromosome 1. Genomic studies have examined this variant for modest statistical associations with skin barrier function, infant atopic dermatitis, and allergic sensitization. However, current clinical evidence for rs11603634 remains limited, indicating that it functions as a weak statistical marker rather than a definitive causal diagnostic mutation.
What each genotype means
Typical skin barrier profile
This genotype represents the most common version of the FLG gene in the general population. It is not associated with the increased risk of skin barrier deficiency or atopic dermatitis linked to FLG-null variants. Having this genotype does not guarantee healthy skin, as other genetic and environmental factors contribute to skin health.
Carried by approximately 88% to 92% of individuals of European ancestry.
Increased atopic risk profile
This genotype indicates you carry one copy of the variant associated with reduced filaggrin production, which is a key protein for maintaining the skin barrier. Research suggests this may increase your susceptibility to atopic dermatitis, dry skin, or secondary allergic conditions like food sensitization. Because this is a risk-associated factor rather than a diagnostic one, many people with this genotype do not develop these conditions.
Carried by roughly 8% to 12% of people of European ancestry.
Elevated skin barrier risk
This genotype indicates you carry two copies of the variant associated with reduced filaggrin production, which can lead to a more significant impairment of the skin's protective barrier. Individuals with this profile are at a higher statistical risk for developing ichthyosis vulgaris, persistent atopic dermatitis, and associated allergic conditions compared to those with one or no copies. Please consult with a dermatologist if you have concerns regarding skin dryness, chronic irritation, or allergic symptoms.
This genotype is rare in the general population, occurring in less than 1% of individuals of European ancestry.
Genomic Context and Variant Architecture
The single-nucleotide polymorphism rs11603634 represents an inherited genomic variation mapped within the filaggrin (FLG) genomic region on chromosome 1q21.3. This chromosomal area is recognized as the epidermal differentiation complex, a dense cluster of genes essential for human skin maturation and cellular cohesion. At this position, standard reference alleles commonly alternate between cytosine (C) and thymine (T). Unlike well-characterized severe loss-of-function null mutations in FLG—such as p.R501X or c.2282del4—which truncate the profilaggrin protein directly, rs11603634 is generally evaluated in large association cohorts as a tag SNP or linked marker. It reflects regional genetic diversity across the epidermal gene cluster, meaning its presence often mirrors broader ancestral haplotypic patterns rather than acting as an isolated protein-altering defect.
The Biological Role of the FLG Gene
The FLG gene encodes profilaggrin, a large, histidine-rich structural precursor protein expressed by keratinocytes in the outermost epidermal layer. Profilaggrin is cleaved into individual filaggrin peptides during terminal differentiation of the stratum corneum. These filaggrin proteins aggregate keratin filaments into tightly packed bundles, establishing a durable physical barrier against environmental pathogens, mechanical stress, and allergens. As epidermal cells shed, filaggrin degrades into hygroscopic free amino acids—collectively termed natural moisturizing factor (NMF)—which retain water and preserve the acidic mantle of healthy skin. When filaggrin production or function is impaired, skin displays increased transepidermal water loss (TEWL) and heightened vulnerability to external irritants and microbial invasion.
Research Findings and Evidence Strength
Research across dermatologic cohorts links filaggrin deficiency to atopic dermatitis (eczema) and the broader atopic march, wherein early barrier impairment allows epicutaneous allergen exposure, potentially driving subsequent food allergies, allergic rhinitis, and childhood asthma. Variant rs11603634 has been cataloged in observational studies assessing infant eczema susceptibility and downstream food sensitization. However, the evidence grade for rs11603634 specifically remains limited. While primary null mutations (such as p.R501X) have robust odds ratios for severe, early-onset eczema, rs11603634 shows weaker, sometimes variable correlations across heterogeneous cohorts. It does not independently guarantee severe dermatitis or allergy development, and researchers view it as an indirect indicator or modest risk modifier rather than a primary driver of atopic pathology.
Population Distribution and Ancestral Patterns
Population frequency data demonstrates notable ancestral stratification for variants within the epidermal differentiation complex. In European cohorts, the minor allele frequency (MAF) of rs11603634 is approximately 0.08 to 0.12, meaning between 8% and 12% of surveyed chromosomes carry the variant allele. Because historical selective pressures, climate adaptations, and population bottlenecks shaped skin barrier genes, filaggrin variants differ substantially in frequency between European, East Asian, and African populations. While specific null mutations are common in Northern Europeans, different loss-of-function variants predominate in Asian or African lineages. For rs11603634, current statistical models and allele distributions are best characterized in European datasets, making direct extrapolation to other ancestral backgrounds scientifically unvalidated.
Practical Implications and Medical Context
Information regarding rs11603634 should be viewed purely as educational data reflecting probabilistic genetic variation. This genetic marker cannot be used to diagnose eczema, predict secondary food allergies, or confirm any medical condition. Atopic dermatitis is an inherently complex, multifactorial disorder influenced by dozens of low-penetrance genetic loci, skin microbiome interactions, indoor and outdoor environmental exposures, and immune system triggers. Carrying a risk-associated genotype does not mean an individual will develop compromised skin integrity, just as carrying typical alleles does not protect against eczema. Anyone experiencing chronic dry skin, inflamed lesions, or suspected food allergies should consult a board-certified dermatologist or allergist for evidence-based diagnostic evaluation and management.
How common is this variant?
The minor allele frequency for rs11603634 is estimated at approximately 0.08 to 0.12 in individuals of European ancestry. Frequencies across other global populations are less extensively cataloged and may reflect significant ancestral divergence.
Frequently asked questions
Does having the rs11603634 variant mean I will get eczema?
No, carrying this variant does not mean you will develop eczema. The association between rs11603634 and atopic dermatitis is weak and probabilistic, not causative. Many people who carry the variant maintain healthy skin throughout their lives.
What is the connection between filaggrin and food allergies?
Filaggrin helps maintain the epidermal barrier that prevents external allergens from penetrating the skin. When the barrier is compromised, early childhood allergen penetration can theoretically provoke an immune response termed the atopic march, potentially increasing the risk of secondary food sensitizations.
Can genetic testing for rs11603634 replace an allergy test?
No, this genetic test cannot diagnose or rule out food or environmental allergies. Clinical allergy diagnoses require standardized medical testing, such as skin-prick testing, serum specific IgE blood tests, and supervised oral challenges conducted by an allergist.
Is rs11603634 considered a severe loss-of-function mutation?
No, rs11603634 is not one of the classic, severe loss-of-function null mutations (such as p.R501X or c.2282del4) that halt filaggrin production. Current evidence classifies it as a marker with limited standalone effect size.
Sources & further reading
Educational information only, last refreshed 9/8/2026. 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.