CFTR rs121913529: Understanding This Rare Genetic Variant
The rs121913529 variant is a rare genetic change located within the CFTR gene, which provides instructions for making a protein that regulates the movement of salt and water in cells. This variant is currently cataloged as a trait-associated marker, and researchers study such variants to understand their potential impact on protein function and human health.
What each genotype means
Typical CFTR function
This genotype represents the common, non-variant sequence at this position in the CFTR gene. It is generally associated with normal CFTR protein function as observed in the general population.
This is the most common genotype found in the general population across all ancestries.
Carrier of variant
This genotype indicates the presence of one copy of the variant allele. As CFTR-related conditions typically follow an autosomal recessive inheritance pattern, carriers are generally asymptomatic but should discuss their status with a genetic counselor or clinician if they are planning a family.
This genotype is rare, occurring at a low frequency in the general population.
Potential CFTR-related disorder
This genotype indicates the presence of two copies of the variant allele. Depending on the specific functional impact of this variant, it may be associated with CFTR-related disorders or clinical symptoms; please consult with a medical geneticist or specialist to interpret these results in the context of your personal health history.
This genotype is extremely rare in the general population.
What is the rs121913529 Variant?
The rs121913529 variant is a specific single nucleotide polymorphism (SNP) found within the CFTR gene. In genomics, a SNP represents a variation at a single position in the DNA sequence. This particular variant is located on chromosome 7, a region that houses the CFTR gene. Because the human genome is vast, scientists use rsIDs like rs121913529 as unique identifiers to track specific locations across different studies. This variant is classified as rare, meaning it is not commonly found in the general population. When researchers identify such variants, they often look at how the change might alter the genetic code and whether that alteration has any observable effect on the biological processes governed by the gene.
The Role of the CFTR Gene
The CFTR gene stands for Cystic Fibrosis Transmembrane Conductance Regulator. It encodes a protein that functions as a channel across the membrane of cells that produce mucus, sweat, saliva, tears, and digestive enzymes. This channel is essential for transporting negatively charged particles called chloride ions into and out of cells. The movement of chloride ions helps control the movement of water in tissues, which is necessary for the production of thin, freely flowing mucus. When the CFTR protein is absent or dysfunctional, the transport of salt and water is disrupted, which can lead to the production of thick, sticky mucus. This process is central to understanding various conditions related to the CFTR gene, as the protein's proper folding and function are critical for maintaining cellular homeostasis.
Research and Evidence Strength
The evidence linking rs121913529 to specific health outcomes is currently categorized as moderate. In genetic research, evidence strength is determined by the consistency and quality of data from clinical studies and population databases. While some variants in the CFTR gene are well-documented as pathogenic, others, like rs121913529, require ongoing investigation to fully characterize their clinical significance. Researchers often use in silico tools—computer models that predict the impact of a genetic change on protein structure—to supplement observational data. Because this variant is rare, there is less clinical data available compared to more common variants. Consequently, scientists remain cautious, often requiring further functional studies or larger cohort data to confirm the exact nature of its association with human traits.
Population Frequency
The rs121913529 variant is considered rare across global populations. In large-scale genomic databases like gnomAD, which aggregate data from hundreds of thousands of individuals, this variant appears at a very low frequency. Rare variants are common in the human genome; in fact, most individuals carry many rare coding variants. Because the frequency is so low, it is difficult to draw broad conclusions about its prevalence in specific ancestral groups. When a variant is this rare, it is often identified in clinical settings rather than general population screenings. Understanding its frequency helps geneticists determine whether a variant is likely to be a common polymorphism or a rare mutation that may have a more significant impact on biological function.
What You Can Do With This Information
Genetic information can be complex, and it is important to approach it with the right perspective. If you have received information about a variant like rs121913529, it is essential to understand that a genetic finding is not a medical diagnosis. Genetic variants are only one piece of a much larger puzzle that includes environment, lifestyle, and other genetic factors. If you are concerned about your health or have questions about genetic testing results, the most appropriate step is to consult with a healthcare professional or a certified genetic counselor. They can help interpret these findings in the context of your personal and family medical history. Never make changes to your health regimen or medication based on genetic data without first discussing it with your clinician or pharmacist.
How common is this variant?
The rs121913529 variant is rare, appearing at a very low frequency across global populations in major genomic databases.
Frequently asked questions
Is rs121913529 a diagnosis for cystic fibrosis?
No, identifying a single genetic variant does not constitute a medical diagnosis. Cystic fibrosis is a complex condition, and a clinical diagnosis is typically made by a physician based on symptoms, sweat chloride testing, and comprehensive genetic analysis.
Where can I find more information about my specific genetic results?
You should discuss any specific genetic findings with a healthcare provider or a genetic counselor. They are trained to interpret these results in the context of your overall health and family history.
Why is this variant called 'rare'?
A variant is labeled 'rare' when it is found in a very small percentage of the population. Most rare variants are not present in the majority of people and are often studied to understand their specific biological effects.
Can I change my genotype?
No, your genotype is determined at conception and remains constant throughout your life. While you cannot change your DNA, understanding your genetic makeup can sometimes help you and your doctor make more informed health decisions.
Sources & further reading
Educational information only, last refreshed 10/8/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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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.
A CFTR mutation associated with cystic fibrosis and CFTR-related disorders.