Is the LPA rs3798220 variant linked to higher lipoprotein(a) and increased coronary heart disease risk?

The LPA gene variant rs3798220 is a critical genetic determinant of cardiovascular health, acting as a major driver of circulating lipoprotein(a) [Lp(a)] concentrations and subsequent coronary heart disease (CHD) risk.

Clinical evidence

• Elevated Lp(a) Phenotype: Carrying the minor C allele of rs3798220 increases plasma Lp(a) levels by an average of approximately 100 nmol/L compared to non-carriers. Homozygous (CC) individuals exhibit severe elevations, with median levels up to 10- to 15-fold higher than reference non-carriers.
• Coronary Heart Disease Risk: Carriers of the risk allele face a 1.3- to 1.7-fold higher risk of CHD or myocardial infarction, with some observational analyses demonstrating adjusted odds ratios as high as 3.14.
• Clinical Utility: The variant is a strong predictor of incident cardiovascular events in primary prevention cohorts, though its impact is ancestry-dependent due to varying allele frequencies, being a low-frequency variant in Europeans and rare in African populations.

Mechanistic explanations

• Isoform Size Regulation: The rs3798220 variant is a missense mutation (producing an Ile4399Met substitution) in the protease-like domain of apolipoprotein(a) [apo(a)]. It serves as a highly penetrant genetic marker in strong linkage disequilibrium with smaller apo(a) isoform sizes characterized by fewer Kringle IV type 2 (KIV-2) repeats.
• Secretion Dynamics: These smaller apo(a) isoforms are synthesized and secreted by hepatocytes at significantly higher rates, leading directly to elevated circulating plasma Lp(a).
• Causal Link: Because LPA variants alter Lp(a) levels without significantly affecting low-density lipoprotein cholesterol (LDL-C), Mendelian randomization studies confirm a lifelong, dose-dependent causal relationship between genetically elevated Lp(a) mediated by this variant and coronary artery disease.

Bottom line

• Bottom line: The LPA rs3798220 variant is robustly associated with highly elevated circulating Lp(a) levels and a significantly increased risk of coronary heart disease. It serves as a powerful genetic proxy for lifelong cardiovascular risk by tagging smaller, highly secreted apolipoprotein(a) isoforms.