HBB rs33915217: Understanding the Hb Malay Variant
The rs33915217 variant is a specific change in the HBB gene that results in the production of an abnormal hemoglobin protein known as Hb Malay. This variant is associated with mild microcytic anemia and is primarily observed in individuals of South Asian ancestry.
What each genotype means
Typical beta-globin profile
This genotype represents the common, non-variant sequence for this specific location in the HBB gene. It is not associated with the beta-thalassemia mutations described for this variant.
This is the most common genotype observed in the general population worldwide.
Beta-thalassemia carrier status
This genotype indicates you carry one copy of the HBB:c.92+5G>C variant, which is a known pathogenic mutation associated with beta-thalassemia. Carriers may exhibit mild microcytic anemia, though clinical presentation can vary significantly based on other genetic factors.
This variant is notably present in Southeast Asian populations, where it has been identified in clinical cohorts.
Beta-thalassemia carrier status
This genotype indicates you carry one copy of the HBB:c.92+5G>T variant, a pathogenic mutation affecting the splice region of the HBB gene. This may lead to reduced production of beta-globin chains, potentially resulting in mild microcytic anemia.
This specific allele is less frequently reported than the G>C substitution but has been identified in clinical studies of beta-thalassemia.
Beta-thalassemia carrier status
This genotype indicates you carry one copy of the HBB:c.92+5G>A variant, which is documented in medical literature as a pathogenic mutation. Carriers should be aware of the potential for mild hematological changes and discuss any concerns with a healthcare provider.
This variant is recognized in clinical databases as a cause of beta-thalassemia, with frequency varying by ancestral background.
What is the rs33915217 Variant?
The rs33915217 variant is a single nucleotide polymorphism (SNP) located within the HBB gene, which provides instructions for making the beta-globin protein. This specific genetic change involves a substitution of a single DNA building block, which leads to an amino acid change (p.Val27Ala) in the resulting protein. This alteration creates a structural hemoglobin variant known as Hb Malay. Because this variant affects the structure of the hemoglobin molecule, it is categorized as a hemoglobinopathy. In the context of genetic testing, this variant is often investigated when individuals present with signs of mild anemia or abnormal results on hemoglobin screening tests. It is important to note that this variant is distinct from the more common mutations that cause severe forms of beta-thalassemia, though it is still classified as a beta-plus thalassemia-related variant due to its impact on hemoglobin production and stability.
The Role of the HBB Gene
The HBB gene is essential for the production of beta-globin, a protein subunit that combines with alpha-globin to form hemoglobin A, the primary oxygen-carrying protein in adult red blood cells. Hemoglobin is responsible for transporting oxygen from the lungs to tissues throughout the body. When the HBB gene contains a variant, the resulting beta-globin protein may be produced in reduced amounts, be unstable, or have an altered structure. These changes can lead to various conditions collectively known as hemoglobinopathies, including beta-thalassemia and sickle cell disease. In the case of rs33915217, the structural change to the beta-globin chain results in the formation of Hb Malay. This variant can interfere with the normal function or stability of hemoglobin, which is why it is associated with clinical findings like microcytic anemia, a condition where red blood cells are smaller than normal and may contain less hemoglobin.
Research and Clinical Associations
Current research identifies rs33915217 as a pathogenic variant for beta-thalassemia, specifically linked to the Hb Malay structural variant. Studies have observed that carriers of this variant may exhibit mild microcytic anemia, characterized by lower corpuscular hemoglobin concentration. The evidence for this association is considered limited in scope, as most clinical data comes from specific population studies rather than large-scale global clinical trials. While it is recognized as a cause of structural hemoglobin variation, the clinical severity can vary significantly between individuals. Because the evidence is based on specific regional cohorts, it is important to interpret these findings within the context of an individual's overall health and family history. Clinicians often use this information to differentiate between various causes of anemia, ensuring that patients receive appropriate diagnostic follow-up if they are found to carry this specific genetic marker.
Population Frequency and Distribution
The distribution of the rs33915217 variant is highly ancestry-specific. It is most frequently observed in South Asian populations, where it has been documented with an allele frequency of approximately 0.4% to 0.5%. In contrast, the variant is almost entirely absent in European and African populations. The higher frequency in South Asian groups may be attributed to factors such as genetic drift, founder effects, or potential historical selective advantages, though these theories remain subjects of ongoing scientific investigation. Because the variant is rare or absent in many global populations, it is not typically included in standard, broad-spectrum genetic screening panels unless specifically requested or indicated by an individual's ethnic background and clinical symptoms. Understanding this population-specific distribution is crucial for genetic counselors and healthcare providers when interpreting test results for patients with unexplained microcytic anemia.
Managing Genetic Information
If you or a family member are identified as a carrier of the rs33915217 variant, it is important to understand that this information is a tool for clinical context, not a medical diagnosis. This variant is associated with mild anemia, but it does not dictate your overall health or quality of life. You cannot change your genetic sequence, but you can use this information to have informed discussions with your healthcare provider. If you are concerned about anemia or other blood-related symptoms, consult a physician or a hematologist who can perform appropriate blood work, such as a complete blood count or hemoglobin electrophoresis. Never make changes to your diet, supplements, or medical treatments based on genetic findings without professional guidance. Always discuss any clinical concerns or potential treatment plans with your clinician, who can provide personalized advice based on your full medical history and current health status.
How common is this variant?
The rs33915217 variant is found at an allele frequency of approximately 0.4% to 0.5% in South Asian populations and is nearly absent in European and African ancestries.
Frequently asked questions
Is rs33915217 the same as sickle cell disease?
No, rs33915217 is a different variant in the HBB gene that causes the production of Hb Malay. While both are hemoglobin variants, they result in different structural changes to the hemoglobin protein and have different clinical implications.
Does having this variant mean I have beta-thalassemia?
The rs33915217 variant is classified as a beta-plus thalassemia-related variant. While it is associated with mild microcytic anemia, a formal diagnosis of beta-thalassemia requires clinical evaluation and blood testing by a medical professional.
Should I be worried if I have this genotype?
Finding this variant is not a cause for immediate alarm, as it is typically associated with mild symptoms. You should discuss the result with your doctor, who can determine if it is relevant to your current health or any symptoms you may be experiencing.
Can I pass this variant to my children?
Yes, like all genetic variants, rs33915217 can be passed from parents to children. If you are concerned about reproductive risks, you may wish to speak with a genetic counselor who can explain the inheritance patterns of HBB variants.
Sources & further reading
Educational information only, last refreshed 10/15/2026. Not medical advice — these associations describe population statistics, not individual predictions.
Curious what your genotype is for rs33915217?
Upload a raw DNA file from 23andMe, AncestryDNA, MyHeritage, or FamilyTreeDNA and see this variant — plus thousands more — interpreted in your full report.
Get my report — $29Related variants in HBB
This variant is a pathogenic mutation in the HBB gene associated with beta-thalassemia.
This variant is a pathogenic mutation in the HBB gene associated with hemoglobinopathies such as sickle cell disease.
This variant (c.20A>T, p.Glu7Val) causes the substitution of valine for glutamic acid in the beta-globin chain, leading to sickle cell trait or disease depending on zygosity.
Pathogenic variant (p.Glu6Val, HbS-Antilles) in HBB associated with sickle cell disease-like pathology.
Pathogenic nonsense mutation (c.118C>T / p.Gln40Ter / codon 39 nonsense) causing beta-zero thalassemia and classic carrier status (beta-thalassemia minor).
This variant, known as Hb C-Harlem, involves a double mutation in the HBB gene that can lead to sickle-beta-thalassemia-like phenotypes.