LOC128772390 rs1290177: What Your Genotype Means
The rs1290177 variant is a single nucleotide polymorphism located in the non-coding regulatory element LOC128772390 on chromosome 13q34. Genome-wide association studies and functional assays have linked this genetic marker to differential enhancer activity in melanocytes and modest variation in cutaneous melanoma susceptibility. While carrying specific alleles correlates with statistical changes in risk across European populations, this variant does not cause or diagnose skin cancer on its own.
What each genotype means
Reduced melanoma risk profile
You carry two copies of the C allele within the LOC128772390 regulatory enhancer element. Genome-wide association studies and functional assays in melanocytes indicate that this genotype is statistically associated with lower baseline susceptibility to cutaneous melanoma compared to carrying the T allele. However, genetic markers only influence baseline risk, and standard sun safety practices remain essential for overall skin health.
Carried by approximately 30% to 45% of individuals of European ancestry, but observed at much lower rates in East Asian and African populations.
Average melanoma susceptibility
You carry one copy of the protective C allele and one copy of the susceptibility-associated T allele at this locus. Research characterizes this as an intermediate genetic profile, conferring a modest relative risk of melanoma compared to the protective homozygous genotype. This genetic signal represents a subtle modifier of risk rather than a deterministic diagnosis, and environmental factors like ultraviolet exposure remain primary contributors to skin cancer risk.
Found in roughly 45% to 50% of individuals of European descent, while being considerably less common across East Asian and African ancestries.
Increased melanoma risk profile
You carry two copies of the T allele in the LOC128772390 enhancer region on chromosome 13q34. In large epidemiological association studies, this genotype has been linked to higher relative susceptibility to cutaneous melanoma via differential enhancer activity in melanocytes. Because this single variant contributes only a small increment to overall risk, routine dermatological evaluations and UV protection remain the standard recommendations regardless of genotype.
Present in roughly 12% to 20% of people of European ancestry and rare to uncommon in East Asian and African populations.
Genomic Context and the LOC128772390 Regulatory Region
The single nucleotide polymorphism rs1290177 is situated at chromosome 13q34 within a non-coding region cataloged in NCBI RefSeq as LOC128772390. Rather than encoding a protein, LOC128772390 has been identified as a functional enhancer—a non-coding DNA stretch that acts as a regulatory switch to modulate the transcription of nearby or distant target genes. Functional genomics experiments using massively parallel reporter assays (MPRAs) in human melanocyte models have demonstrated that the DNA sequence spanning rs1290177 exhibits significant transcriptional regulatory activity. The two alleles at rs1290177 drive measurably distinct levels of gene expression in skin pigment cells, defining LOC128772390 as an allele-specific enhancer. Because regulatory sequences dictate when and how intensely target genes are switched on, single base changes within enhancers can shape cellular responses to environmental stressors such as ultraviolet (UV) radiation without altering the amino acid sequence of any single protein.
Scientific Evidence and Association with Melanoma Risk
Melanoma susceptibility loci have been uncovered through large-scale international collaborations analyzing thousands of melanoma cases alongside healthy controls. In genome-wide association studies (GWAS) investigating cutaneous melanoma, genomic variations within the 13q34 locus have shown statistically significant associations with disease risk. At rs1290177, the common reference allele has been characterized as exerting a protective or lower-risk effect, whereas the alternate allele correlates with a modest increase in baseline risk in case-control cohorts. Massively parallel functional screens confirmed that rs1290177 is one of the functional driver candidates in this locus because it directly alters enhancer potency in cultured melanocytes. However, the overall strength of evidence for rs1290177 in clinical practice is considered moderate and low-penetrance. Unlike high-risk familial mutations in tumor suppressor genes such as CDKN2A, common polygenic variants like rs1290177 alter baseline susceptibility by only small increments rather than causing hereditary cancer syndromes.
Ancestry Patterns and Population Frequencies
Allele distributions for rs1290177 display considerable genetic divergence across global human ancestral groups. The variant allele is relatively common among individuals of European ancestry, where the minor allele frequency (MAF) consistently ranges between approximately 0.35 and 0.45 across large population sequencing datasets such as gnomAD. In contrast, the alternate allele is substantially less frequent in East Asian and African ancestral populations, where the reference allele is fixed or near fixation. This population differentiation is an essential nuance in genomics: the statistical risk associations and functional models generated for rs1290177 were predominantly studied in cohorts of European descent. Consequently, calculating polygenic liability using this locus cannot be extrapolated equally across all global ancestries without adjusting for underlying baseline allele frequencies and differing linkage disequilibrium patterns.
Clinical Utility and What You Can Do
It is critical to distinguish between common regulatory variants and actionable diagnostic mutations. Having one or two copies of a risk-associated allele at rs1290177 does not mean you will develop melanoma, nor does carrying protective alleles make you immune to sun damage or skin malignancies. Common variants like rs1290177 contribute small fractions to an individual's overall polygenic background, which interacts continuously with major established factors such as ultraviolet light exposure, history of severe sunburns, fair skin complexion, and total mole (nevus) count. Genetic tests reporting common variants cannot be used to diagnose cancer or replace professional medical screenings. The most effective strategies for reducing melanoma risk remain behavioral and clinical: using broad-spectrum sunscreen, seeking shade during peak daylight hours, wearing protective clothing, and undergoing periodic skin examinations by a dermatologist or healthcare professional if you notice changing, asymmetrical, or irregular skin lesions.
How common is this variant?
The variant allele at rs1290177 is common in European populations with a minor allele frequency between 0.35 and 0.45, but it is observed at much lower frequencies in African and East Asian populations.
Frequently asked questions
Does having the higher-risk rs1290177 genotype mean I will get melanoma?
No. The rs1290177 variant is a common, low-penetrance regulatory marker that only contributes a small incremental difference to baseline risk in population studies. Most people with one or two risk alleles never develop melanoma, as environmental exposures like UV radiation and broader polygenic factors play a dominant role.
What is the LOC128772390 region and what does it do?
LOC128772390 is a non-protein-coding genomic region on chromosome 13 that functions as an enhancer element. Enhancers act as molecular switches that regulate how strongly nearby genes are transcribed, and the rs1290177 variant alters this regulatory activity specifically in melanocytes.
Can this genetic test replace my regular skin exam?
No. Genetic testing for rs1290177 cannot diagnose melanoma or evaluate existing moles. Routine skin self-examinations and professional evaluations by a dermatologist remain the gold standard for detecting abnormal lesions and managing skin health.
Are the risk associations for rs1290177 the same for all ethnic backgrounds?
No. Most research on rs1290177 has been conducted in European ancestry populations, where the variant is common. Because the variant is significantly less frequent in African and East Asian populations, its statistical association cannot be assumed to apply uniformly across all ancestries.
Sources & further reading
Educational information only, last refreshed 9/14/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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