CFTR rs113993960: Understanding the DeltaF508 Mutation
The rs113993960 variant in the CFTR gene, widely known as the DeltaF508 mutation, is the most frequent genetic cause of cystic fibrosis worldwide. It involves a specific deletion of three DNA base pairs that results in a dysfunctional chloride channel protein.
What each genotype means
Cystic Fibrosis carrier
This genotype indicates you are a carrier of the DeltaF508 mutation, meaning you have one copy of the mutation and one normal copy of the CFTR gene. Carriers are typically unaffected by cystic fibrosis, though some research has explored potential associations with other respiratory conditions like asthma. You should discuss your carrier status with a genetic counselor or clinician if you are planning a family.
This genotype is carried by roughly 1 in 25 people of European ancestry, making it a common genetic finding in these populations.
Typical CFTR genotype
This genotype indicates that you do not carry the DeltaF508 mutation at this specific location in the CFTR gene. Your genetic profile at this position is considered the normal or reference state. This result does not rule out the presence of other, less common mutations in the CFTR gene that could be associated with cystic fibrosis.
This is the most common genotype observed in the general population across all ancestries.
What is the rs113993960 Variant?
The rs113993960 variant is a well-studied genetic alteration located on chromosome 7 within the CFTR gene. Scientifically referred to as the DeltaF508 mutation, it is characterized by the deletion of three nucleotides (CTT) in the DNA sequence. This specific deletion leads to the loss of a single amino acid, phenylalanine, at position 508 of the resulting CFTR protein. Because this change occurs within the coding region of the gene, it significantly impacts the structure and stability of the protein. First identified in 1989, this variant is the most common mutation associated with cystic fibrosis, accounting for approximately 70% of all cystic fibrosis cases globally. It is classified as a pathogenic variant due to its strong, well-documented association with the development of the condition when inherited in a recessive manner.
The Role of the CFTR Gene
The CFTR gene provides instructions for creating the cystic fibrosis transmembrane conductance regulator protein. This protein functions as a channel across the membranes of cells that produce mucus, sweat, saliva, tears, and digestive enzymes. Its primary job is to transport 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 missing or dysfunctional—as is the case with the DeltaF508 mutation—chloride transport is impaired. This leads to the production of thick, sticky mucus that can clog airways and ducts in various organs, particularly the lungs and pancreas, which is the hallmark of cystic fibrosis.
Research and Clinical Associations
Research into rs113993960 is extensive, as it is the primary focus of many studies regarding cystic fibrosis. Cystic fibrosis is an autosomal recessive disorder, meaning an individual must typically inherit two copies of a non-functional CFTR variant to manifest the classic disease. Individuals who are homozygous for the DeltaF508 mutation (carrying two copies) often experience severe symptoms. However, some individuals may be compound heterozygotes, meaning they carry one copy of the DeltaF508 mutation and a different, separate mutation in the other copy of the CFTR gene. The severity of the condition can vary based on the specific combination of mutations present. Current research also explores how this variant influences the efficacy of CFTR modulator therapies, which are designed to improve the function of the protein in specific genetic contexts.
Understanding Your Results
Genetic testing for the rs113993960 variant is often performed to determine carrier status or to assist in the diagnosis of cystic fibrosis. If you have received information about your genotype for this variant, it is important to understand that this is a complex medical topic. Being a carrier (having one copy of the variant) generally does not cause the symptoms of cystic fibrosis, but it does mean there is a possibility of passing the variant to offspring. If you are concerned about your results or your family history, you should consult with a genetic counselor or a medical professional. They can provide context based on your specific health history and help you understand the implications of your genetic data. Never use genetic information to make medical decisions without professional guidance, especially regarding potential treatments or reproductive planning.
How common is this variant?
The DeltaF508 mutation is most prevalent in populations of European descent, where the carrier frequency is approximately 1 in 25. It is found at lower frequencies in other ethnic groups.
Frequently asked questions
What does it mean to be a carrier of the DeltaF508 mutation?
Being a carrier means you have one copy of the mutated gene and one normal copy. Carriers typically do not show symptoms of cystic fibrosis but can pass the mutation to their children.
Is rs113993960 the only mutation that causes cystic fibrosis?
No, there are over 1,000 known mutations in the CFTR gene that can cause cystic fibrosis. DeltaF508 is simply the most common one identified.
Can I use this information to diagnose myself?
No. Genetic testing results should always be interpreted by a qualified healthcare provider or genetic counselor. They can explain what the results mean in the context of your overall health.
Are there treatments for people with the DeltaF508 mutation?
Yes, there are CFTR modulator therapies available that help improve the function of the protein. You should discuss these options and their suitability with a specialist, such as a pulmonologist.
Sources & further reading
Educational information only, last refreshed 10/9/2026. 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.