Does Lipoprotein(a) increase total apoB particle burden and does the LPA rs3798220 variant raise Lp(a) and cardiovascular risk?

Clinical evidence

• Direct Cardiovascular Risk: Strong scientific evidence establishes that both Lipoprotein(a) [Lp(a)] levels and the LPA rs3798220 genetic variant are strongly associated with adverse cardiovascular outcomes. Large-scale prospective studies, such as the Women's Health Study, show that carriers of the LPA rs3798220 risk allele (p.Ile4399Met) have a highly elevated risk of cardiovascular events, showing an approximate 2.2-fold higher hazard ratio.
• Coronary Heart Disease and Aortic Stenosis: In comprehensive cohorts like the UK Biobank, the rs3798220 risk allele is consistently associated with a stepwise increase in coronary heart disease and early-onset myocardial infarction (hazard ratio of approximately 1.2 to 1.3 per risk allele). Beyond ischemic events, carrying this variant is also associated with a significantly increased risk of calcific aortic valve stenosis, expanding its clinical impact to valvular heart disease.

Mechanistic explanations

• Stoichiometry and Particle Burden: Lp(a) is structurally characterized as an apolipoprotein B-100 (apoB-100) containing lipoprotein particle. It consists of an LDL-like core with exactly one molecule of apoB-100 covalently bound to a single apolipoprotein(a) glycoprotein via a disulfide bridge. Because of this strict 1:1 molecular stoichiometry, each Lp(a) particle directly contributes to and increases the total measured plasma apolipoprotein B particle burden.
• Assay Overlap: Standard clinical assays measuring total apolipoprotein B assess the sum of all atherogenic apoB-containing particles (including VLDL, IDL, LDL, and Lp(a)). Consequently, every circulating Lp(a) particle is counted as a single apoB particle within standard assays. While Lp(a) represents about 3% of the total apoB pool in the general population, it can contribute 15% or more to the overall apoB particle burden in individuals with highly elevated Lp(a) levels.
• Genetic Influence: The LPA rs3798220 variant is a low-frequency, high-impact missense variant. Together with rs10455872, it explains nearly 40% of the variance in circulating Lp(a) concentrations in European populations, driving plasma levels well above standard clinical risk thresholds (e.g., >50 mg/dL). Once absolute Lp(a) concentrations are accounted for, the genotype itself does not add incremental prognostic value, confirming that the excess cardiovascular risk is mediated by the elevated Lp(a) particle count.

Bottom line

• Lipoprotein(a) is an apoB-containing lipoprotein particle that directly increases the total measured apolipoprotein B particle burden due to its 1:1 apoB-100 stoichiometry. The LPA rs3798220 variant is a powerful genetic driver of markedly elevated circulating Lp(a) levels and is strongly associated with an increased risk of coronary heart disease, early-onset myocardial infarction, and calcific aortic valve stenosis.