CFTR rs113633875: What Your Genotype Means
The rs113633875 variant is a specific change in the CFTR gene, which provides instructions for a protein vital to fluid and mucus regulation in the body. Research associates this variant with cystic fibrosis, a condition that can have significant impacts on respiratory, digestive, and reproductive health.
What each genotype means
Typical genetic profile
This is the most common genotype observed in the general population at this location. Current research identifies this site as a DNase I hypersensitive region within the CFTR gene, which may function as a regulatory element; however, carrying the typical alleles does not indicate an association with cystic fibrosis or reproductive health conditions.
This is the predominant genotype found in the vast majority of individuals across all major global ancestries.
Variant carrier
You carry one copy of the less common allele at this position. Because this variant is located in a regulatory region within CFTR intron 18a, researchers investigate such sites to understand how they might influence gene expression, though current evidence does not establish this specific variant as a primary cause of cystic fibrosis or related reproductive health conditions.
This genotype is rare, occurring at low frequencies in the general population.
Rare variant genotype
You carry two copies of the less common allele at this position. This variant is located within a potential regulatory region of the CFTR gene, which is critical for chloride transport. While this site is of interest to researchers studying how non-coding regions influence CFTR function, there is currently no consensus that this specific genotype alone leads to clinical disease or reproductive health impact.
This genotype is very rare, observed infrequently in population-level genomic databases.
Understanding the rs113633875 Variant
The rs113633875 variant is located within the CFTR gene, specifically situated in a DNase I hypersensitive site within intron 18a. In genomics, a single nucleotide polymorphism (SNP) like rs113633875 represents a variation at a single position in the DNA sequence. While many SNPs have no observable effect on health, this variant is situated in a region of the CFTR gene that is currently under scientific investigation due to its potential role in gene regulation or RNA processing. By residing in a DNase I hypersensitive site—an area of open chromatin often associated with gene regulation—this variant is studied for how it might alter the instructions the cell uses to produce or regulate the CFTR protein. Understanding these regulatory regions is a key focus of modern genetics, as they can influence how much protein is produced even if the protein's structure itself remains unchanged.
The Role of the CFTR Gene
The CFTR gene encodes the Cystic Fibrosis Transmembrane Conductance Regulator protein. This protein acts as a specialized channel on the surface of cells, regulating the movement of chloride ions and water across cell membranes. Proper function of this channel is essential for maintaining the balance of fluids in various organs, including the lungs, pancreas, and reproductive tract. When the CFTR gene contains variants that disrupt the protein's production or function, it can lead to the production of thick, sticky mucus. This blockage can impair organ function, which is the hallmark of cystic fibrosis. Because the CFTR protein is also involved in the reproductive system, variants in this gene are clinically relevant to studies of reproductive health. Disruptions in this pathway can lead to various clinical manifestations, making the study of CFTR variants a priority for understanding hereditary conditions.
Research and Evidence
Current scientific literature categorizes the evidence linking rs113633875 to health outcomes as moderate. This means that while there is an observed statistical association between this variant and cystic fibrosis, the clinical impact for any single individual can be complex. Because cystic fibrosis is an autosomal recessive condition—meaning it typically requires two pathogenic variants (one inherited from each parent) to manifest clinical symptoms—the presence of this variant must be considered within the context of a person’s entire genetic profile. Researchers continue to use functional assays and large-scale genetic databases to determine exactly how variants in intronic, regulatory regions like intron 18a contribute to the overall burden of CFTR-related conditions. Always consult with a healthcare professional or a genetic counselor to interpret genetic information in the context of your personal and family medical history, as genetic associations are not definitive predictors of health outcomes.
Your Genotype and What You Can Do
Genetic information is a tool for understanding biological predispositions, but it is not a diagnosis. If you have received information about this variant, it is important to understand that your genotype represents only one piece of your overall health picture. You cannot use this information to self-diagnose or alter medical treatments. If you are concerned about your results, the most effective step is to schedule an appointment with a genetic counselor or a medical specialist who can review your findings alongside your clinical history. They can provide context on whether this variant is relevant to your specific health goals or family planning needs. Remember that genetic testing is a complex field, and professional guidance is essential for accurate interpretation. For any concerns regarding genetic health or medication, always discuss your findings with your clinician or pharmacist.
How common is this variant?
The rs113633875 variant is classified as rare across global populations. Its frequency can vary significantly depending on ancestral background, a common observation in genetic epidemiology.
Frequently asked questions
What does intronic mean?
An intron is a non-coding section of a gene. While introns do not provide the direct instructions for building a protein, they play essential roles in regulating how a gene is expressed and how the final genetic message is assembled.
Does this variant guarantee I have cystic fibrosis?
No. Cystic fibrosis is a complex condition, and genetic variants are only part of the picture. A genetic test result is not a medical diagnosis; please consult a doctor to interpret these findings.
Can I use this information to change my medication?
Never change your medication based on genetic test results without consulting your doctor or pharmacist. They are the only ones who can safely integrate this information into your treatment plan.
Why is this variant considered higher-attention?
In genomics, higher-attention simply denotes that the variant has been linked to a health condition in scientific research. It serves as a prompt to seek professional medical guidance to understand your specific health context.
Where can I find more research on this variant?
You can explore resources like the NCBI SNP database or ClinVar to view the most recent clinical and research data associated with specific genetic variants.
Sources & further reading
Educational information only, last refreshed 9/15/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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A nonsense variant in the CFTR gene with high clinical evidence and practice guideline support for cystic fibrosis management.
Severe pathogenic mutation (p.Gly542Ter) associated with cystic fibrosis.
Classic cystic fibrosis in-frame 3-bp deletion variant (p.Phe508del / deltaF508) causing misfolding and impaired chloride channel trafficking.
Pathogenic frameshift mutation (c.3659delC) in CFTR linked to cystic fibrosis.
Pathogenic nonsense variant (p.Gly542Ter / G542X) causing autosomal recessive cystic fibrosis when inherited in trans with another CFTR pathogenic allele.
Also known as p.Arg117His (R117H), this CFTR variant is associated with mild or atypical cystic fibrosis and congenital bilateral absence of the vas deferens, with clinical severity influenced by the poly-T tract background.