TP53 rs121913281: Understanding the p.Arg273His Variant
The rs121913281 variant in the TP53 gene is a rare, pathogenic genetic change known as p.Arg273His. It is strongly associated with Li-Fraumeni syndrome, a condition that significantly increases the lifetime risk of developing various types of cancer.
What each genotype means
Typical TP53 profile
This genotype represents the most common genetic sequence at this specific location in the TP53 gene. It is considered the reference sequence and is not associated with the pathogenic hotspot mutation described in clinical literature.
This is the predominant genotype found in the vast majority of the global population.
Pathogenic TP53 variant carrier
This genotype indicates the presence of the p.Arg273His pathogenic hotspot variant in the TP53 gene. Research associates this specific change with an increased risk for early-onset cancers, including sarcomas, breast cancers, and leukemias. Individuals with this result should consult with a genetic counselor or oncologist to discuss appropriate clinical screening and surveillance.
This genotype is extremely rare, with an observed allele frequency of less than 0.00005 in large-scale population databases.
Homozygous pathogenic variant
This genotype indicates that both copies of the TP53 gene carry the p.Arg273His pathogenic hotspot variant. This condition is associated with a significantly elevated risk for early-onset malignancies and requires professional medical evaluation. Please discuss these findings with a clinical geneticist or oncologist to understand the implications for your health and potential screening needs.
This genotype is exceptionally rare and has not been observed in major population reference cohorts.
What is rs121913281?
The variant rs121913281, often referred to in clinical literature as p.Arg273His or c.818G>A, is a specific change in the DNA sequence of the TP53 gene. Located on chromosome 17, this variant involves a single nucleotide substitution where the amino acid arginine is replaced by histidine at position 273 of the p53 protein. This specific site is considered a 'hotspot' because it is a frequent location for mutations that disrupt the protein's normal function. Because this variant is classified as pathogenic, it is recognized by medical genetics experts as a significant alteration that can impair the body's ability to suppress tumor growth. It is typically identified through clinical genetic testing when there is a strong family history of early-onset cancers.
The Role of the TP53 Gene
The TP53 gene provides instructions for making a protein called p53, which acts as a tumor suppressor. This protein is often described as the 'guardian of the genome' because it plays a critical role in maintaining cellular stability. When DNA damage occurs, the p53 protein helps determine whether the cell should repair the damage or undergo programmed cell death, known as apoptosis. By preventing cells with mutated or damaged DNA from dividing, p53 effectively stops the development of tumors. When a pathogenic variant like rs121913281 is present, the p53 protein may lose its ability to bind to DNA or regulate these essential cell-cycle checkpoints, allowing damaged cells to proliferate uncontrollably and increasing the risk of malignancy.
Clinical Associations and Evidence
Research strongly associates the rs121913281 variant with Li-Fraumeni syndrome (LFS), a rare, inherited cancer predisposition disorder. Individuals who carry this germline variant have a significantly higher lifetime risk of developing a wide spectrum of cancers, including early-onset breast cancer, sarcomas, leukemias, and adrenal cortical carcinomas. The evidence for this association is robust, with the ClinGen TP53 Variant Curation Expert Panel classifying it as pathogenic for autosomal dominant Li-Fraumeni syndrome. Because the clinical impact is profound, medical guidelines emphasize the importance of specialized surveillance for carriers. It is important to note that while the association with cancer risk is well-documented, the specific age of onset and the type of cancer can vary significantly even among family members carrying the same variant.
Population Frequency
The rs121913281 variant is extremely rare in the general population. Because it is a pathogenic germline mutation associated with a severe cancer predisposition syndrome, it is not typically found at high frequencies in large-scale genomic databases. Its frequency is estimated to be well below 0.00005. This rarity underscores that the variant is not a common polymorphism found in the general public but rather a specific, high-impact mutation that is usually identified in the context of clinical diagnostic testing for individuals or families with a history of hereditary cancer syndromes.
Managing Genetic Information
If you or a family member have been identified as a carrier of the rs121913281 variant, it is essential to consult with a certified genetic counselor or an oncologist specializing in hereditary cancer syndromes. This information is highly sensitive and carries significant clinical implications for long-term health monitoring. You cannot 'treat' or 'change' this genetic variant, but you can use this knowledge to engage in proactive, evidence-based cancer surveillance programs that may allow for earlier detection of potential issues. Do not make medical decisions based on raw data or online reports; always discuss your results and the appropriate clinical management plan with your healthcare provider. They can provide context based on your personal and family medical history, which is vital for interpreting the significance of this finding.
How common is this variant?
The rs121913281 variant is extremely rare in the general population, with a germline frequency estimated at less than 0.00005.
Frequently asked questions
What is Li-Fraumeni syndrome?
Li-Fraumeni syndrome is a rare, inherited disorder that significantly increases the risk of developing various types of cancer at a young age. It is most commonly caused by pathogenic germline mutations in the TP53 gene.
Does having this variant mean I will definitely get cancer?
While this variant is associated with a significantly increased lifetime risk of cancer, it does not mean a diagnosis is inevitable. Genetic predisposition is complex, and many factors, including other genetic modifiers and environmental influences, play a role in cancer development.
How is this variant tested?
Testing for this variant is typically performed through clinical genetic testing, often ordered by a medical geneticist or oncologist. It involves analyzing a blood or saliva sample to sequence the TP53 gene.
What should I do if I have this variant?
If you are a carrier, you should consult with a genetic counselor and a specialist in hereditary cancer syndromes. They will help you develop a personalized surveillance plan to monitor your health and manage your risks.
Sources & further reading
Educational information only, last refreshed 9/20/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Pathogenic missense variant (p.Arg248Gln) associated with Li-Fraumeni syndrome.
Functional codon 72 polymorphism (Arg72Pro) affecting apoptotic capability and associated with differential susceptibility to multiple cancer types.
Functional 3' UTR polyadenylation signal polymorphism altering TP53 transcription termination, showing population-specific baseline carrier frequencies across global groups.
Li-Fraumeni syndrome missense variant (p.Arg248Trp) causing loss of tumor suppressor function and multi-cancer predisposition.
Synonymous and regulatory variant in linkage with TP53 codon 72 that modulates blastocyst implantation competence and the risk of recurrent implantation failure.
3' UTR hypomorphic variant in TP53 that impairs proper polyadenylation and significantly confers elevated risk for basal cell carcinoma, glioma, and other cancers.