SLC45A2 rs11603330: What Your Genotype Means
The rs11603330 variant is a genetic change located within the SLC45A2 gene, which plays a key role in human pigmentation. Research suggests this variant acts as a regulatory marker associated with normal variations in skin and hair color across diverse human populations.
What each genotype means
Associated with lighter pigmentation
This genotype is associated with variations in normal human skin, hair, and eye pigmentation. Research suggests this variant may influence melanin production, contributing to lighter pigmentation phenotypes in certain populations.
This genotype is common in European populations, where the C allele is frequently observed.
Intermediate pigmentation association
Carrying one copy of each allele may result in an intermediate influence on pigmentation traits compared to homozygous genotypes. As this is a regulatory variant, the exact phenotypic expression can be influenced by other genetic and environmental factors.
This heterozygous genotype is found at significant frequencies in populations with mixed ancestral backgrounds.
Associated with darker pigmentation
This genotype is associated with variations in normal human skin, hair, and eye pigmentation, often correlating with darker pigmentation traits. The SLC45A2 gene plays a role in melanosome function, and this specific variant is one of several factors that influence natural pigment variation.
This genotype is more common in African and certain other non-European populations where the G allele is more prevalent.
Understanding the Variant
The rs11603330 variant is a single nucleotide polymorphism (SNP) situated in the promoter region of the SLC45A2 gene. In genetics, a promoter is a specific sequence of DNA that acts as an on-off switch for a gene, determining how much of a protein is produced. Because rs11603330 is located in this regulatory area, it is thought to influence the expression levels of the SLC45A2 protein rather than changing the structure of the protein itself. This variant is cataloged in public databases as a trait-associated marker, meaning it is statistically linked to observable physical characteristics. While it is a subject of interest in dermatological and evolutionary genetics, it is important to note that the evidence linking this specific SNP to pigmentation is considered limited compared to other well-studied coding variants in the same gene.
The Role of the SLC45A2 Gene
The SLC45A2 gene, also known as MATP, provides the blueprint for a transport protein found within melanocytes. Melanocytes are specialized cells responsible for producing melanin, the pigment that determines the color of our skin, hair, and eyes. The SLC45A2 protein is located in the membrane of melanosomes, which are the tiny structures inside cells where melanin synthesis occurs. By regulating the internal environment of these melanosomes—specifically by helping to manage pH levels—the protein ensures that melanin is produced efficiently. When this gene functions normally, it contributes to the standard range of human pigmentation. Conversely, rare and severe mutations in this gene can disrupt melanin production entirely, leading to conditions such as oculocutaneous albinism type 4. However, common variants like rs11603330 are associated with the natural, healthy spectrum of human pigment diversity rather than disease.
Research and Evidence
Scientific research has identified the SLC45A2 gene as a major contributor to human pigmentation differences. While coding variants like L374F (rs16891982) are well-documented for their strong association with lighter skin and hair, the evidence for rs11603330 is more nuanced. Studies in the GWAS Catalog and other genomic resources classify this variant as a regulatory SNP. Its association with pigmentation is observed through statistical correlations in large population studies, where researchers look for patterns between specific DNA sequences and physical traits. Because pigmentation is a polygenic trait—meaning it is influenced by many different genes working in concert—the individual effect size of any single regulatory SNP like rs11603330 is typically small. Consequently, while the association is recognized in the literature, it is not considered a definitive predictor of an individual's appearance.
Population Frequency
The frequency of the rs11603330 variant varies significantly across different ancestral groups. Data indicates that this variant is relatively common in European populations, with a minor allele frequency (MAF) of approximately 0.4. In contrast, the variant is found at a much lower frequency in African populations. These differences in allele frequency are a common feature of genes involved in pigmentation, reflecting historical evolutionary pressures related to geography and sunlight exposure. Because the variant is common in some groups and rare in others, it serves as a useful marker for researchers studying human migration and the evolution of skin color. It is important to remember that these frequencies are population-level averages and do not dictate the specific genotype of any single individual.
Interpreting Your Information
If you have received information about your rs11603330 genotype, it is helpful to view it as a small piece of a much larger biological puzzle. This variant is associated with normal human variation and is not a diagnostic tool for any medical condition. You cannot use this information to predict your exact skin or hair color, as these traits are determined by the complex interaction of many genes, environmental factors, and developmental processes. If you are interested in learning more about your genetic makeup, consider discussing your results with a qualified genetic counselor who can provide context based on your personal and family history. Always remember that genetic associations are statistical in nature and do not represent a fixed destiny for your physical traits or health outcomes.
How common is this variant?
The rs11603330 variant is common in European populations with a minor allele frequency of approximately 0.4, while it appears at a significantly lower frequency in African populations.
Frequently asked questions
Is rs11603330 a cause of albinism?
No, rs11603330 is a common variant associated with normal variation in pigmentation. Oculocutaneous albinism type 4 is caused by rare, severe mutations that disrupt the function of the SLC45A2 protein.
Can I use this SNP to predict my child's eye color?
No, this SNP is not a reliable predictor of eye color. Pigmentation is a complex trait influenced by many different genes, and a single SNP cannot provide a definitive prediction.
What does it mean if my genotype is 'neutral'?
A 'neutral' repute means that the variant is considered a normal part of human genetic diversity. It is not associated with any known disease or health risk.
Why is the evidence for this variant called 'limited'?
Evidence is labeled as limited when the statistical association is not as strong or consistent as other well-established markers. It suggests that more research is needed to fully understand the variant's specific role.
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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This synonymous variant is in high linkage disequilibrium with functional alleles that influence human skin, hair, and eye pigmentation.
This missense variant (p.Phe374Leu) is a major determinant of human skin, hair, and eye pigmentation, showing strong evidence of selection in European populations.
Synonymous marker in the SLC45A2 locus associated with skin reflectance, tanning response, and freckling phenotypes.
This missense variant (p.Phe374Leu) is a key ancestry-informative marker and a classic signature of recent positive selection, strongly associated with skin pigmentation and melanoma risk.
This variant (p.Phe374Leu) is strongly associated with lighter skin, hair, and eye pigmentation, as well as an increased sensitivity to UV-induced skin damage.
The p.Phe374Leu variant in SLC45A2 is a major determinant of human pigmentation variation, influencing skin, hair, and eye color across global populations.