What you carry at this position in your DNA and what research says about it.
Thyroid and Heart Health: 9/10 evidence, 16 publications.
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Sample genotype (not yours): C/C
Typical Heart and Thyroid Risk Profile
Standard apolipoprotein H function maintains typical baseline risks for thyroid and cardiovascular conditions. There is no genetic elevation in muscle or liver injury biomarkers associated with this genotype.
What this genotype means: Typical thyroid hormone levels; Standard heart rhythm susceptibility; Normal baseline muscle and liver biomarkers.
Sample genotype (not yours): C/G
Slightly Elevated Heart and Thyroid Risks
Carrying one copy of the G allele is associated with slightly lower thyroid-stimulating hormone levels and a minor increase in the risk of hyperthyroidism. It also slightly elevates the risk of atrial fibrillation and muscle injury biomarkers.
What this genotype means: Slightly lower thyroid-stimulating hormone levels; Modestly increased risk of atrial fibrillation; Slightly elevated baseline creatine kinase.
Sample genotype (not yours): G/G
Mixed Cardiovascular and Thyroid Profile
Carrying two copies of the G allele significantly lowers thyroid-stimulating hormone levels and raises hyperthyroidism and atrial fibrillation risks. However, it also offers protective benefits, including a reduced risk of deep vein thrombosis.
What this genotype means: Significantly lower thyroid-stimulating hormone levels; Increased risk of atrial fibrillation; Elevated baseline creatine kinase and AST levels.
Gene function and biological role
Gene Function: The APOH gene encodes apolipoprotein H, also known as beta-2-glycoprotein I, which is a multifunctional protein circulating in human plasma. It binds to negatively charged phospholipid surfaces and is heavily involved in lipid metabolism, blood coagulation, and the clearance of apoptotic cells. Beyond its classic roles in cardiovascular physiology and hemostasis, apolipoprotein H has been implicated in thyroid hormone regulation and autoimmune responses [1] [2]. Alterations in this gene can influence susceptibility to cardiovascular conditions, metabolic traits, and thyroid disorders [3].
Variant Impact: The rs1801690 variant is a missense change in the APOH gene that substitutes the amino acid tryptophan with serine at position 335 (p.Trp335Ser). This structural alteration in the apolipoprotein H protein affects its binding affinity and circulating levels, leading to downstream systemic effects. Research shows this specific amino acid change significantly alters thyroid-stimulating hormone levels and thyroid function [2]. Additionally, the variant is linked to altered levels of muscle and liver biomarkers, as well as changes in cardiovascular risk profiles [4] [5].
Key Insight: This single amino acid change in a lipid-binding protein simultaneously influences thyroid hormone regulation, heart rhythm susceptibility, and blood clotting dynamics.
Location: APOH. Chromosome 17 · 17q24.2 · 66.2 Mb
Estimated prevalence by population
Global 92.1%; European 89.4%; African 98.3%; East Asian 86.4%; South Asian 90.0%; Americas 93.8%; Ashkenazi 92.4%; Finnish 86.4%; Middle Eastern 91.9%; Amish 92.7%.
Estimated CC genotype frequency.
Global 7.7%; European 10.3%; African 1.7%; East Asian 13.1%; South Asian 9.7%; Americas 6.1%; Ashkenazi 7.4%; Finnish 13.1%; Middle Eastern 7.9%; Amish 7.2%.
Estimated CG genotype frequency.
Global 0.2%; European 0.3%; African < 0.1%; East Asian 0.5%; South Asian 0.3%; Americas 0.1%; Ashkenazi 0.1%; Finnish 0.5%; Middle Eastern 0.2%; Amish 0.1%.
Estimated GG genotype frequency.
Showing effects for C/C genotype
Endocrine & Reproductive
Hormone Levels & Endocrine Regulation
Thyroid Function. Evidence: 9/10. Source: PMID 32769997. Typical TSH Levels.
Cardiovascular & Metabolic
Heart Rhythm & Conduction
Heart Rhythm. Evidence: 8/10. Source: PMID 40645996. Typical Risk.
Coagulation & Clotting
Blood Clot Risk. Evidence: 8/10. Source: PMID 29403010. Typical Risk.
Nutrition & Metabolism
Blood Chemistry & Metabolites
Creatine Kinase Levels. Evidence: 8/10. Source: PMID 29403010. Typical Levels.
Showing effects for C/G genotype
Thyroid Function. Evidence: 9/10. Source: PMID 32769997. Slightly Lower TSH.
Heart Rhythm. Evidence: 8/10. Source: PMID 40645996. Slightly Higher Risk.
Blood Clot Risk. Evidence: 8/10. Source: PMID 29403010. Slightly Lower Risk.
Creatine Kinase Levels. Evidence: 8/10. Source: PMID 29403010. Slightly Elevated.
Showing effects for G/G genotype
Thyroid Function. Evidence: 9/10. Source: PMID 32769997. Lower TSH Levels.
Heart Rhythm. Evidence: 8/10. Source: PMID 40645996. Higher Risk.
Blood Clot Risk. Evidence: 8/10. Source: PMID 29403010. Lower Risk.
Creatine Kinase Levels. Evidence: 8/10. Source: PMID 29403010. Elevated Levels.
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
Maintaining two copies of the reference C allele ensures standard production of functional apolipoprotein H. This genotype is associated with typical baseline levels of thyroid-stimulating hormone, helping maintain normal thyroid function [1]. It also carries a standard baseline risk for atrial fibrillation and typical levels of cardiac troponin I [2] [3]. Biomarkers of muscle and liver status, such as creatine kinase and aspartate aminotransferase, remain within normal ranges [4] [5]. While this genotype does not benefit from the reduced blood clotting risks seen in variant carriers, it avoids the elevated risks of hyperthyroidism and heart rhythm issues.
Typical thyroid hormone levels; Standard heart rhythm susceptibility; Normal baseline muscle and liver biomarkers.
Sample genotype: CG (Heterozygous)
Possessing one copy of the G allele introduces a modified apolipoprotein H protein that alters systemic physiological pathways. This genetic change is linked to a slight reduction in thyroid-stimulating hormone levels, which can marginally increase the risk of hyperthyroidism or thyrotoxicosis [1]. It also correlates with a modest increase in susceptibility to atrial fibrillation and elevated cardiac troponin I [2] [3]. Furthermore, levels of creatine kinase and aspartate aminotransferase may be slightly elevated, indicating a higher baseline for muscle and liver biomarkers [4] [5]. On the positive side, this genotype may experience a slight reduction in deep vein thrombosis risk and carotid artery thickness.
Slightly lower thyroid-stimulating hormone levels; Modestly increased risk of atrial fibrillation; Slightly elevated baseline creatine kinase.
Sample genotype: GG (Homozygous)
Having two copies of the G allele leads to the exclusive production of the serine-335 variant of apolipoprotein H. This genotype is associated with the lowest levels of thyroid-stimulating hormone, which significantly increases the risk of hyperthyroidism and thyrotoxicosis [1]. It also carries the highest genetic susceptibility to atrial fibrillation and elevated cardiac troponin I [2] [3]. Baseline levels of creatine kinase and aspartate aminotransferase are typically elevated, which is important to note when interpreting routine lab tests [4] [5]. Conversely, this genotype benefits from a lower risk of deep vein thrombosis and reduced carotid artery wall thickness, presenting a unique physiological trade-off.
Significantly lower thyroid-stimulating hormone levels; Increased risk of atrial fibrillation; Elevated baseline creatine kinase and AST levels; Reduced risk of deep vein thrombosis.
Variants with shared genetic architecture
rs1801689 · APOH Gene · Chr 17 · Cholesterol and Lipid Levels
rs11052877 · CD69 Gene · Chr 12 · Thyroid Disease Risk
rs11773845 · CAV1 Gene · Chr 7 · Atrial Fibrillation Risk
Uncovering the shared genetic components of thyroid disorders and reproductive health.
Genome-wide association study of cardiac troponin I in the general population.
Content updated August 2026.
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