What you carry at this position in your DNA and what research says about it.
Immune and Heart Health: 9/10 evidence, 17 publications.
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Sample genotype (not yours): G/G
Normal Immune Defense and Typical Heart Risk
Normal levels of mannose-binding lectin support a robust first-line defense against bacterial and viral infections. This typical genotype is also associated with a lower risk of developing coronary artery disease and myocardial infarction compared to deficiency states.
What this genotype means: Normal mannose-binding lectin levels; Typical defense against bacterial infections; Typical risk of myocardial infarction.
Sample genotype (not yours): A/A
Weakened Immune Defense and Higher Heart Risk
Two copies of the variant allele cause a severe deficiency in mannose-binding lectin. This deficiency significantly impairs the innate immune response to pathogens and is linked to an increased risk of infections and heart attacks.
What this genotype means: Severe mannose-binding lectin deficiency; Increased susceptibility to bacterial and viral infections; Higher risk of myocardial infarction and arterial stiffness.
Sample genotype (not yours): G/A
Slightly Reduced Immune Defense and Heart Protection
Carrying one copy of the variant allele leads to moderately reduced levels of mannose-binding lectin. While most carriers remain healthy, there is a slightly increased susceptibility to certain infections and cardiovascular events under physiological stress.
What this genotype means: Moderately reduced mannose-binding lectin levels; Slightly increased susceptibility to infections under stress; Slightly higher risk of myocardial infarction.
Gene function and biological role
Gene Function: Mannose-binding lectin 2 encodes a key soluble protein of the innate immune system that recognizes and binds to carbohydrate patterns on the surface of various pathogens [1]. Once bound, it activates the complement system via the lectin pathway, promoting phagocytosis and direct destruction of invading microorganisms [1]. It also plays a role in clearing dying host cells and inflammatory debris, helping to maintain tissue homeostasis [2]. Genetic variations that alter expression or structure can lead to functional mannose-binding lectin deficiency [1]. This deficiency is one of the most common primary immunodeficiencies in humans, though many affected individuals remain healthy unless otherwise compromised [2].
Variant Impact: The rs5030737 variant is a missense mutation in exon 1 of the MBL2 gene, resulting in an amino acid substitution from arginine to cysteine at codon 52, often designated as the D allele [1]. This structural change disrupts the proper assembly of the protein's collagen-like triple helix, leading to rapid degradation of the protein subunits [1]. Consequently, individuals carrying the variant allele experience a drastic reduction in functional circulating mannose-binding lectin levels [3]. This functional deficiency impairs the body's ability to recognize and clear certain pathogens, particularly in early childhood or during immunosuppression [4]. It also influences susceptibility to chronic inflammatory conditions and cardiovascular events [5].
Key Insight: A single amino acid change in the MBL2 gene can drastically reduce circulating levels of mannose-binding lectin, impacting both the body's ability to fight off infections and its long-term cardiovascular health.
Location: MBL2. Chromosome 10 · 10q21.1 · 52.8 Mb
Estimated prevalence by population
Global 90.5%; European 86.1%; African 97.7%; East Asian 99.9%; South Asian 89.0%; Americas 92.4%; Ashkenazi 81.2%; Finnish 88.2%; Middle Eastern 94.6%; Amish 71.1%.
Estimated GG genotype frequency.
Global 9.2%; European 13.4%; African 2.3%; East Asian 0.1%; South Asian 10.7%; Americas 7.4%; Ashkenazi 17.9%; Finnish 11.4%; Middle Eastern 5.3%; Amish 26.4%.
Estimated GA genotype frequency.
Global 0.3%; European 0.5%; African < 0.1%; East Asian < 0.1%; South Asian 0.3%; Americas 0.1%; Ashkenazi 1.0%; Finnish 0.4%; Middle Eastern 0.1%; Amish 2.5%.
Estimated AA genotype frequency.
Showing effects for G/G genotype
Immunity & Inflammation
Inflammatory & Circulating Protein Markers
MBL Protein Levels. Evidence: 9/10. Source: PMID 34648354. Normal Levels.
Infection Susceptibility & Resistance
Infection Risk. Evidence: 4/10. Source: PMID 20463618. Typical Risk.
Tuberculosis. Evidence: 3/10. Source: PMID 22417159. Typical Risk.
Cardiovascular & Metabolic
Heart Disease
Heart Attack. Evidence: 3/10. Source: PMID 22848725. Typical Risk.
Showing effects for A/A genotype
MBL Protein Levels. Evidence: 9/10. Source: PMID 34648354. Deficient Levels.
Infection Risk. Evidence: 4/10. Source: PMID 20463618. Higher Risk.
Tuberculosis. Evidence: 3/10. Source: PMID 22417159. Higher Risk.
Heart Attack. Evidence: 3/10. Source: PMID 22848725. Higher Risk.
Showing effects for G/A genotype
MBL Protein Levels. Evidence: 9/10. Source: PMID 34648354. Reduced Levels.
Infection Risk. Evidence: 4/10. Source: PMID 20463618. Slightly Higher Risk.
Tuberculosis. Evidence: 3/10. Source: PMID 22417159. Slightly Higher Risk.
Heart Attack. Evidence: 3/10. Source: PMID 22848725. Slightly Higher Risk.
What this genotype means for the people who carry it
Sample genotype: GG (Homozygous)
Maintaining normal circulating levels of mannose-binding lectin ensures that the innate immune system can efficiently tag and destroy invading pathogens [1]. This genotype represents the most common, fully functional state of the MBL2 gene, providing optimal complement pathway activation [1]. Research indicates that having normal MBL levels is protective against severe infections, particularly in vulnerable populations like infants or those undergoing chemotherapy [2]. Furthermore, large-scale cohort studies, such as the HUNT2 study, have demonstrated that individuals with normal MBL levels have a significantly lower risk of myocardial infarction compared to those with genetic deficiency [3]. The protein's role in clearing cellular debris and regulating vascular inflammation is thought to help prevent the progression of atherosclerosis [3]. Consequently, this genotype is considered highly favorable for both infectious disease defense and cardiovascular health.
Normal mannose-binding lectin levels; Typical defense against bacterial infections; Typical risk of myocardial infarction.
Sample genotype: AA (Homozygous)
Having two copies of the cysteine-encoding variant allele prevents the proper formation of functional mannose-binding lectin, leading to a profound deficiency of the protein in circulation [1]. This severe deficiency compromises the lectin pathway of the complement system, making it harder for the body to neutralize bacteria, viruses, and fungi [2]. The clinical impact is most pronounced in early childhood before adaptive immunity matures, or in adults with compromised immune systems [2]. Research has demonstrated a significant association between this deficiency state and an increased risk of severe infections, including neonatal sepsis and pulmonary tuberculosis [3]. Furthermore, the lack of functional MBL is linked to accelerated atherosclerosis and a doubled risk of myocardial infarction [4]. Despite these risks, many individuals with this genotype lead normal lives, as other arms of the immune system often compensate for the deficiency.
Severe mannose-binding lectin deficiency; Increased susceptibility to bacterial and viral infections; Higher risk of myocardial infarction and arterial stiffness.
Sample genotype: GA (Heterozygous)
A single copy of the cysteine-encoding variant allele partially disrupts the assembly of the mannose-binding lectin protein, resulting in intermediate circulating levels [1]. Under normal circumstances, this moderate reduction is of low clinical importance, and most individuals do not experience obvious health issues [2]. However, during periods of immune challenge, such as neonatal development, chemotherapy, or immunosuppressive therapy, the lower protein levels can slightly compromise pathogen clearance [2]. Studies have also linked intermediate MBL levels to a modest increase in the risk of respiratory infections and tuberculosis [3]. Additionally, the reduction in MBL's ability to clear inflammatory debris in blood vessels may slightly elevate the risk of developing coronary artery disease and myocardial infarction [4]. While the risk increase is small, maintaining a healthy lifestyle and staying up-to-date on vaccinations can help mitigate these subtle vulnerabilities.
Moderately reduced mannose-binding lectin levels; Slightly increased susceptibility to infections under stress; Slightly higher risk of myocardial infarction.
Variants with shared genetic architecture
rs1800450 · MBL2 Gene · Chr 10 · Innate Immune Defense
rs1800451 · MBL2 Gene · Chr 10 · MBL Immune Protein
rs7095891 · MBL2 Gene · Chr 10 · Immune System Function
Phylogenetic nomenclature and evolution of mannose-binding lectin (MBL2) haplotypes.
Mapping the proteo-genomic convergence of human diseases.
Role of polymorphic variants as genetic modulators of infection in neonatal sepsis.
DNA sequence variation and regulation of genes involved in pathogenesis of pulmonary tuberculosis.
Content updated August 2026.
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