FGFR3 rs121913483: Understanding the p.Ser249Cys Variant
The rs121913483 variant is a rare genetic change located in the FGFR3 gene that results in a specific protein alteration known as p.Ser249Cys. This variant has been identified in research as a pathogenic mutation associated with certain types of cancer, including bladder urothelial carcinoma.
What each genotype means
Typical FGFR3 profile
This is the most common genotype, representing the typical sequence for the FGFR3 gene at this position. It is not associated with the specific pathogenic risks linked to the variant described in clinical literature.
This is the reference genotype found in the vast majority of the human population.
Pathogenic variant carrier
This genotype indicates the presence of the p.Ser249Cys mutation on one chromosome. This specific variant is recognized as pathogenic and is frequently studied in the context of bladder urothelial carcinoma, where it may influence tumor biology and potential therapeutic responses; please discuss any clinical concerns or surveillance needs with your healthcare provider.
This genotype is extremely rare in the general population.
Pathogenic variant homozygous
This genotype indicates the presence of the p.Ser249Cys mutation on both chromosomes. This variant is documented as pathogenic and is associated with oncogenic activity in bladder urothelial carcinoma; individuals with this finding should consult with a medical professional or genetic counselor to understand the clinical implications for their health.
This genotype is exceptionally rare and is not typically observed in general population databases.
What is rs121913483?
The variant rs121913483, often referred to by its protein-level change p.Ser249Cys, is a specific alteration in the DNA sequence of the FGFR3 gene. In genetic terms, this is a missense variant, meaning that a single nucleotide change leads to the substitution of one amino acid for another in the resulting protein. Specifically, the amino acid serine is replaced by cysteine at position 249. This variant is located on chromosome 4. Because it involves a change in the protein's structure, researchers study it to understand how it might affect the normal function of the receptor. It is categorized in clinical databases as a pathogenic variant, which indicates that it has been documented to contribute to disease processes rather than being a benign variation found in the general population.
The Role of the FGFR3 Gene
The FGFR3 gene provides the blueprint for the fibroblast growth factor receptor 3 protein. This protein is a member of a family of receptors that play critical roles in various biological processes, including the regulation of cell growth, division, and maturation. Specifically, FGFR3 is essential for the development and maintenance of bone and cartilage tissues. When a signaling molecule binds to the receptor, it triggers a cascade of signals inside the cell that tells the cell how to behave. Because this pathway is so fundamental to cell cycle control, mutations that alter the receptor's activity can lead to abnormal cell growth. In the context of cancer research, the FGFR3 gene is frequently studied because its dysregulation can contribute to the uncontrolled cell proliferation characteristic of certain tumors.
Research Associations and Evidence
Scientific literature has established a link between the p.Ser249Cys variant and bladder urothelial carcinoma. In these contexts, the variant is often described as oncogenic, meaning it has the potential to promote tumor development. The evidence for this association is considered moderate to strong in the context of cancer genomics, as the mutation has been identified in tumor samples. It is important to note that the presence of this variant in a tumor does not necessarily mean it is the sole cause of the disease, as cancer development is typically a complex, multi-step process involving many genetic and environmental factors. Researchers continue to investigate how this specific amino acid change alters the receptor's signaling activity, potentially keeping the 'growth' signal turned on even when it should be off.
Population Frequency
The rs121913483 variant is classified as rare in the general population. Large-scale genomic databases, such as gnomAD, show that this specific allele is found at an extremely low frequency across diverse ancestral groups. Because it is so rare, it is not typically screened for in standard population-wide genetic testing. The scarcity of this variant in healthy individuals underscores its clinical significance; when it is found, it is usually in the context of specific clinical investigations rather than as a common polymorphism. The limited data available in public databases reflects its status as a rare pathogenic variant rather than a common genetic trait shared by many people.
Interpreting Your Genetic Information
If you encounter this variant in a genetic report, it is essential to understand that this information is for educational purposes and does not constitute a medical diagnosis. Genetic variants associated with cancer risk are complex, and their presence does not guarantee that an individual will develop a disease. If you have concerns about your genetic health or family history, the most appropriate step is to consult with a qualified healthcare provider or a genetic counselor. They can help interpret your results in the context of your personal health history and provide guidance on whether further clinical evaluation is necessary. Never make medical decisions based solely on raw genetic data without professional clinical oversight.
How common is this variant?
The rs121913483 variant is extremely rare in the general population, with an allele frequency near zero in most major ancestral groups tracked by genomic databases.
Frequently asked questions
Is rs121913483 a cancer-causing mutation?
The variant is associated with bladder urothelial carcinoma and is considered pathogenic in that context. However, having this variant does not mean you will definitely develop cancer, as disease development is complex.
Should I be worried if I have this variant?
If you have received a report mentioning this variant, you should discuss it with a healthcare professional or a genetic counselor. They can provide context based on your personal and family health history.
Where can I find more information about FGFR3?
You can find reliable information about the FGFR3 gene and its functions on resources like MedlinePlus Genetics or the GeneCards database. These sites provide comprehensive overviews of gene function and associated conditions.
Is this variant inherited?
While some FGFR3 variants are inherited, others can occur as somatic mutations, meaning they arise in specific cells during a person's lifetime. Clinical testing can help determine the nature of a specific finding.
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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