BCMO1 rs7501331: What Your Genotype Means
The rs7501331 variant is a specific change in the BCMO1 gene that has been linked to differences in how efficiently the body converts dietary provitamin A carotenoids into vitamin A. Research suggests that individuals carrying the variant allele may experience reduced enzymatic activity, potentially impacting their vitamin A metabolism.
What each genotype means
Typical carotenoid conversion
You carry two copies of the common C allele at rs7501331, which corresponds to typical beta-carotene 15,15'-monooxygenase (BCMO1) enzyme activity. Published nutritional research indicates that individuals with this genotype convert plant-derived provitamin A carotenoids, such as beta-carotene, into active vitamin A at baseline efficiency. However, overall vitamin A levels still depend on your broader diet, general absorption, and other genetic variants such as rs12934922.
Carried by approximately 55% to 80% of individuals across diverse global ancestries, though it is notably less prevalent in some African populations where the alternate allele is rare or absent.
Moderately reduced carotenoid conversion
You carry one copy of the T allele (often noted as the A379V missense change), which has been linked to moderately decreased catalytic activity of the BCMO1 enzyme. In population studies, carriers of a T allele show reduced efficiency in converting provitamin A carotenoids from plant sources into active retinoids, particularly when co-inherited with other BCMO1 variants like rs12934922. Because this is an observational trait influenced by overall dietary intake, having this genotype does not cause vitamin deficiency on its own.
Carried by approximately 20% to 40% of individuals in European, East Asian, and Southeast Asian populations.
Reduced carotenoid conversion
You carry two copies of the T allele for rs7501331, which encodes the BCMO1 379V enzyme variant associated with significantly reduced enzymatic cleavage of dietary carotenoids. Research shows that homozygous carriers may experience slower conversion of plant-based beta-carotene into retinal and higher fasting plasma carotenoid levels, with effects being most pronounced if variant alleles at rs12934922 are also present. These statistical findings reflect metabolic conversion efficiency rather than a clinical diagnosis, and maintaining diverse dietary vitamin A sources typically meets physiological needs.
Carried by roughly 1% to 6% of individuals across European and Asian ancestries, and it is virtually absent in certain West African populations.
Understanding the rs7501331 Variant
The rs7501331 variant is a single nucleotide polymorphism (SNP) located within the BCMO1 gene, which is situated on chromosome 16. In genetics, a SNP represents a variation at a single position in the DNA sequence. Specifically, rs7501331 is a nonsynonymous coding variant, meaning the change in the DNA sequence results in an amino acid substitution—in this case, an alanine to valine change at position 379 (A379V). Because this change occurs within the coding region of the gene, it has the potential to alter the structure or function of the protein that the gene encodes. Scientists study these variants to understand how subtle differences in our genetic code contribute to the wide range of metabolic diversity observed among humans.
The Role of the BCMO1 Gene
The BCMO1 gene provides instructions for producing an enzyme called beta-carotene 15,15'-monooxygenase. This enzyme plays a critical role in human nutrition by cleaving dietary provitamin A carotenoids, such as beta-carotene, into retinal, which is a form of vitamin A. Vitamin A is essential for vision, immune function, and skin health. Because the body cannot synthesize vitamin A on its own, it relies on the conversion of these plant-based pigments. When the BCMO1 enzyme functions optimally, the body efficiently processes these carotenoids. However, if the enzyme's activity is reduced due to genetic variations, the conversion process may become less efficient, which can influence how much active vitamin A an individual derives from their diet.
Research and Evidence Strength
Research into rs7501331 is considered to have limited evidence regarding its clinical impact. Studies, such as those published in journals like PubMed, have observed that the variant allele (T) is associated with reduced catalytic activity of the BCMO1 enzyme in both in vitro and in vivo settings. Some research indicates that this variant often acts in an additive manner with another common SNP, rs12934922. When individuals carry the variant alleles for both SNPs, the combined effect may lead to a more pronounced reduction in the ability to convert beta-carotene into retinyl esters. While these findings are statistically significant in specific study cohorts, the overall clinical significance remains a subject of ongoing investigation, and it is not currently used as a diagnostic tool for vitamin A deficiency.
Population Frequency
The frequency of the rs7501331 variant varies across different global populations. In many studies, the minor allele (T) is observed at a frequency of approximately 0.10 to 0.24, depending on the ancestry of the group being studied. For example, research involving Filipino populations has reported genotype frequencies where the CC genotype is the most common, followed by the CT heterozygote and the TT homozygote. Because allele frequencies are highly dependent on ancestral background, these numbers should not be generalized to all individuals. Understanding these frequencies helps researchers determine how common these metabolic variations are within the general population and provides context for why some individuals may have different dietary requirements for vitamin A.
Interpreting Your Genetic Information
It is important to understand that having a specific genotype for rs7501331 does not constitute a medical diagnosis. Genetic associations are statistical observations made across large groups of people and do not necessarily predict an individual's health outcomes. Factors such as overall diet, lifestyle, and other genetic variants also play significant roles in vitamin A status. If you are concerned about your nutritional intake or vitamin levels, you should consult with a healthcare professional or a registered dietitian. They can provide personalized guidance based on your clinical history and blood work. Never use genetic information to make changes to your diet or supplement regimen without first discussing these decisions with a qualified clinician or pharmacist.
How common is this variant?
The minor allele (T) frequency is approximately 0.10 to 0.24 in various populations, with genotype distributions typically following Hardy-Weinberg equilibrium.
Frequently asked questions
Does the rs7501331 variant cause vitamin A deficiency?
No, this variant is not a direct cause of vitamin A deficiency. It is associated with the efficiency of converting dietary beta-carotene into vitamin A, but many other factors, including total dietary intake, influence your actual vitamin A levels.
Should I take vitamin A supplements if I have the T allele?
You should not change your supplement regimen based on genetic results alone. Please discuss your nutritional needs and any potential supplementation with your doctor or a registered dietitian.
Is this variant related to eye health?
Some research has investigated whether BCMO1 variants affect macular pigment optical density, which is relevant to eye health. However, current evidence is mixed, and no definitive link has been established for this specific SNP.
Can I get a test for this variant?
This variant is often included in direct-to-consumer genetic testing panels. However, because the clinical evidence is limited, the results are primarily for educational purposes and should not be used for medical decision-making.
Sources & further reading
Educational information only, last refreshed 10/11/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Missense variant in beta-carotene oxygenase 1 that significantly reduces catalytic efficiency of dietary beta-carotene conversion into active retinol.
Influences the enzymatic conversion efficiency of dietary beta-carotene into active vitamin A (retinol).
This coding variant reduces beta-carotene 15,15'-monooxygenase activity, impairing the enzymatic conversion of provitamin A carotenoids into active retinal.