rs6939340: Understanding the 6p22 Neuroblastoma Risk Variant
The rs6939340 variant is a common single-nucleotide polymorphism located on chromosome 6p22. Research has identified a statistical association between this variant and an increased risk of developing clinically aggressive neuroblastoma in children.
What each genotype means
Baseline risk profile
This genotype represents the baseline state for this genetic variant. Research indicates that individuals with this genotype do not carry the specific risk alleles associated with increased susceptibility to aggressive neuroblastoma at this locus.
This is the most common genotype observed in the general population.
Increased neuroblastoma risk
Carrying one copy of the G allele is associated with a statistically significant increase in the risk of developing aggressive neuroblastoma compared to those with the A/A genotype. This association is based on large-scale genome-wide association studies, though the absolute risk for any individual remains low.
This heterozygous genotype is commonly found across diverse human populations.
Elevated neuroblastoma risk
Homozygosity for the G allele is associated with a higher statistical risk of developing clinically aggressive neuroblastoma compared to individuals with the A/A or A/G genotypes. While this variant is a known risk factor, it is important to note that most individuals with this genotype will not develop the condition.
This genotype is present in a significant portion of the population, though it is less common than the A/A genotype.
What is rs6939340?
The rs6939340 variant is a single-nucleotide polymorphism (SNP) located in an intergenic region on the short arm of chromosome 6, specifically at the 6p22.3 locus. In genetics, a SNP represents a variation at a single position in the DNA sequence among individuals. While this specific SNP does not sit within the protein-coding sequence of a gene, it is situated near regions that have been identified as important in the context of neuroblastoma susceptibility. Specifically, it is often discussed in relation to the CASC15 and NBAT1 genes. Because it is located in a non-coding region, researchers study it to understand how it might influence the regulation or expression of nearby genes rather than how it alters a protein's structure directly. It is one of several genetic markers identified through genome-wide association studies (GWAS) that have helped scientists map the complex genetic architecture of pediatric cancers.
The Association with Neuroblastoma
The primary research interest in rs6939340 stems from its statistical link to neuroblastoma, a type of cancer that develops from immature nerve cells. Large-scale studies, including genome-wide association studies, have consistently observed that individuals carrying the G allele at this position show a higher statistical likelihood of developing the disease. Specifically, homozygosity for the G allele (having two copies of the G variant) has been associated with an increased risk of developing clinically aggressive forms of neuroblastoma. It is important to note that this is a statistical association observed in populations, not a diagnostic test. The presence of this variant does not mean an individual will develop cancer, as neuroblastoma is a complex disease influenced by many genetic and environmental factors. The evidence for this association is considered moderate to strong in the scientific literature, having been replicated across multiple independent case-control studies.
Population Frequency and Context
The rs6939340 variant is considered a common polymorphism, meaning the minor allele is present at a significant frequency across various human populations. Because it is common, a large number of healthy individuals carry one or two copies of the G allele without ever developing neuroblastoma. This highlights the fact that while the variant is a risk factor, it is not a direct cause of the disease. The frequency of the G allele can vary between different ancestral groups, which is a common feature of many genetic variants identified by GWAS. Researchers continue to study these frequency differences to better understand how genetic background influences disease risk. When interpreting such data, it is essential to remember that the vast majority of people who carry this common variant will never be diagnosed with neuroblastoma, as the absolute risk remains low for the general population.
What This Information Means for You
Understanding your genetic profile regarding rs6939340 is a matter of scientific interest rather than clinical utility for the general public. Because neuroblastoma is a rare condition and the association with this SNP is based on population-level statistics, this information cannot be used to predict an individual's health outcome or to guide medical care. If you have concerns about family history or specific health risks, the most appropriate step is to consult with a qualified healthcare professional or a genetic counselor. They can provide context based on your personal and family medical history, which is far more predictive than any single genetic variant. Avoid using genetic data from direct-to-consumer tests to make medical decisions or to assess personal cancer risk. Always rely on clinical evaluations and professional medical advice for any health-related concerns.
How common is this variant?
The rs6939340 variant is a common polymorphism found across diverse populations, with the G allele appearing at a significant frequency in many ancestral groups.
Frequently asked questions
Does having the G/G genotype mean I will get neuroblastoma?
No. The association between rs6939340 and neuroblastoma is based on population statistics, not individual prediction. The vast majority of people with the G/G genotype will never develop the disease.
Is rs6939340 a diagnostic test for cancer?
No, this SNP is not used as a diagnostic tool. Neuroblastoma is a complex disease, and clinical diagnosis is based on physical exams, imaging, and biopsy results, not genetic testing of common variants.
Why is this variant called 'intergenic'?
The term intergenic means the variant is located in the DNA sequence between genes. It does not sit inside a gene that codes for a protein, though it may still influence how nearby genes are regulated.
Should I be worried if I have the G allele?
There is no reason for concern. Because this is a common variant, many healthy people carry the G allele. It is a small piece of a much larger genetic puzzle and does not determine your health status.
Sources & further reading
Educational information only, last refreshed 10/13/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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