What you carry at this position in your DNA and what research says about it.
Anemia Risk: 7/10 evidence, 9 publications.
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Sample genotype (not yours): C/C
Typical Red Blood Cell Health
You carry two copies of the common, fully functional version of the PKLR gene. This means you have a typical risk of pyruvate kinase deficiency and normal red blood cell levels.
What this genotype means: Typical red blood cell lifespan; Normal hemoglobin levels.
Sample genotype (not yours): C/T
Pyruvate Kinase Deficiency Carrier
You carry one copy of the pathogenic T allele, making you a healthy carrier of pyruvate kinase deficiency. You are highly unlikely to experience symptoms of anemia yourself, but you can pass the variant to your children.
What this genotype means: Carrier of pyruvate kinase deficiency; Slightly lower pyruvate kinase levels.
Sample genotype (not yours): T/T
High Risk of Pyruvate Kinase Deficiency
You carry two copies of the pathogenic T allele, which is strongly linked to hereditary nonspherocytic hemolytic anemia. This can cause your red blood cells to break down prematurely, leading to chronic fatigue and other symptoms.
What this genotype means: High risk of hemolytic anemia; Significantly reduced red blood cell lifespan.
Gene function and biological role
Gene Function: The PKLR gene provides instructions for making pyruvate kinase, a key enzyme involved in glycolysis, the process that breaks down glucose for energy [1]. In red blood cells, this enzyme is vital because these cells lack mitochondria and depend entirely on glycolysis to produce adenosine triphosphate (ATP) [2]. ATP is essential for maintaining the cell's shape and flexibility as it travels through blood vessels [2]. Insufficient pyruvate kinase activity causes red blood cells to break down prematurely, a process called hemolysis [3]. This premature destruction can lead to hereditary nonspherocytic hemolytic anemia, where the body lacks enough healthy red blood cells to carry oxygen [3].
Variant Impact: The rs113403872 variant is a missense mutation in the PKLR gene that changes the amino acid arginine to glutamine at position 510 of the protein (p.Arg510Gln) [1]. This specific amino acid substitution alters the structural stability and catalytic efficiency of the pyruvate kinase enzyme [1]. Research shows that this mutation significantly reduces the enzyme's activity in red blood cells [1]. Because the enzyme cannot function properly, red blood cells experience energy depletion and are destroyed prematurely by the spleen [3]. This variant is one of the well-documented genetic causes of autosomal recessive pyruvate kinase deficiency [4].
Key Insight: Red blood cells rely entirely on a single enzyme-driven pathway for energy because they lack mitochondria, making them uniquely vulnerable to PKLR mutations.
Location: PKLR. Chromosome 1 · 1q22 · 155.3 Mb
Estimated prevalence by population
Global 99.9%; European 99.8%; African 99.9%; East Asian 100.0%; South Asian 100.0%; Americas 100.0%; Ashkenazi 100.0%; Finnish 100.0%; Middle Eastern 100.0%; Amish 100.0%.
Estimated CC genotype frequency.
Global 0.1%; European 0.2%; African 0.1%; East Asian 0.0%; South Asian 0.0%; Americas 0.0%; Ashkenazi 0.0%; Finnish 0.0%; Middle Eastern 0.0%; Amish 0.0%.
Estimated CT genotype frequency.
Global < 0.1%; European < 0.1%; African < 0.1%; East Asian 0.0%; South Asian 0.0%; Americas 0.0%; Ashkenazi 0.0%; Finnish 0.0%; Middle Eastern 0.0%; Amish 0.0%.
Estimated TT genotype frequency.
Showing effects for C/C genotype
Cardiovascular & Metabolic
Blood Cell & Iron Traits
Anemia. Evidence: 7/10. Source: PMID 17360088. Typical Risk.
Hemoglobin Levels. Evidence: 10/10. Source: PMID 32888494. Typical.
Red Blood Cell Count. Evidence: 8/10. Source: PMID 32888494. Typical.
Hematocrit. Evidence: 7/10. Source: PMID 32888494. Typical.
Pyruvate Kinase Levels. Evidence: 10/10. Source: PMID 39789286. Typical.
Showing effects for C/T genotype
Anemia. Evidence: 7/10. Source: PMID 17360088. Carrier (No Disease).
Hemoglobin Levels. Evidence: 10/10. Source: PMID 32888494. Slightly Lower.
Red Blood Cell Count. Evidence: 8/10. Source: PMID 32888494. Slightly Lower.
Hematocrit. Evidence: 7/10. Source: PMID 32888494. Slightly Lower.
Pyruvate Kinase Levels. Evidence: 10/10. Source: PMID 39789286. Slightly Lower.
Showing effects for T/T genotype
Anemia. Evidence: 7/10. Source: PMID 17360088. High Risk.
Hemoglobin Levels. Evidence: 10/10. Source: PMID 32888494. Significantly Lower.
Red Blood Cell Count. Evidence: 8/10. Source: PMID 32888494. Significantly Lower.
Hematocrit. Evidence: 7/10. Source: PMID 32888494. Significantly Lower.
Pyruvate Kinase Levels. Evidence: 10/10. Source: PMID 39789286. Significantly Lower.
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
Two copies of the common C allele ensure that your PKLR gene produces fully functional pyruvate kinase enzymes [1]. These enzymes are crucial for maintaining the energy levels and structural integrity of your red blood cells [2]. As a result, your body is able to maintain typical levels of hemoglobin, hematocrit, and red blood cells [3]. You do not carry the pathogenic mutation associated with hereditary nonspherocytic hemolytic anemia [4]. This genotype is highly common, occurring in over 99% of the global population. No special dietary or medical interventions are needed based on this genetic result. Your red blood cells should function normally and live their full lifespan of about 120 days. Maintaining a balanced diet rich in iron and vitamins supports this natural cellular health.
Typical red blood cell lifespan; Normal hemoglobin levels.
Sample genotype: CT (Heterozygous)
Inheriting one copy of the T allele makes you a carrier of pyruvate kinase deficiency, an autosomal recessive condition [1]. Because you have one fully functional C allele, your body produces enough active pyruvate kinase to keep your red blood cells healthy [2]. Studies show that carriers typically have normal or only slightly lower hemoglobin and red blood cell counts [3]. You are highly unlikely to experience the premature red blood cell destruction or chronic fatigue associated with the disease [4]. However, if your partner is also a carrier, there is a 25% chance of passing the active condition to your children [1]. Knowing your carrier status can be valuable for family planning. Most carriers live completely normal, healthy lives without ever knowing they have this variant.
Carrier of pyruvate kinase deficiency; Slightly lower pyruvate kinase levels.
Sample genotype: TT (Homozygous)
Two copies of the mutated T allele cause your body to produce a highly dysfunctional version of the pyruvate kinase enzyme [1]. Without sufficient enzyme activity, your red blood cells cannot generate enough energy to maintain their structure, causing them to rupture prematurely [2]. This rapid destruction of red blood cells leads to hereditary nonspherocytic hemolytic anemia, characterized by low hemoglobin and hematocrit levels [3]. Symptoms can range from mild fatigue and jaundice to severe anemia requiring blood transfusions [4]. This is a rare genetic condition that typically presents in childhood or early adulthood [4].
High risk of hemolytic anemia; Significantly reduced red blood cell lifespan.
Variants with shared genetic architecture
rs116100695 · PKLR Gene · Chr 1 · Red Blood Cell Health
rs2075672 · TFR2 Gene · Chr 7 · Iron and Blood Health
rs6014993 · MIR5095 Gene · Chr 20 · Red Blood Cell Size
Pyruvate kinase deficiency: the genotype-phenotype association.
The Polygenic and Monogenic Basis of Blood Traits and Diseases.
Content updated August 2026.
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