rs6507931 — LIPG

LIPG — The HDL Phospholipase Gene

Endothelial lipase (EL) is an enzyme secreted by vascular endothelial cells that hydrolyzes the phospholipid coat of HDL particles¹¹ HDL particles
high-density lipoprotein — the "good cholesterol" responsible for reverse cholesterol transport from arteries to the liver. Higher endothelial lipase activity degrades HDL faster, lowering both HDL particle count and size. The LIPG gene encodes this enzyme, and rs6507931 is an intronic variant that modulates its expression — with the T allele associated with altered HDL dynamics, particularly under sedentary conditions.

The Mechanism

rs6507931 sits in intron 24 of LIPG (c.1155-108, transcript variant 2) on chromosome 18q21.1. As an intronic variant it does not change the amino acid sequence of the EL protein, but it likely affects splicing efficiency or transcriptional regulation of LIPG expression. Higher LIPG expression means more phospholipid hydrolysis of HDL particles, producing smaller, cholesterol-depleted HDL remnants and reducing overall HDL-C. The T allele tags a haplotype associated with this pattern of increased EL activity, especially when physical activity levels are low — aerobic exercise is known to suppress LIPG expression in striated muscle tissue, protecting HDL from excessive degradation.

The Evidence

The primary evidence for rs6507931 comes from the GOLDN study²² GOLDN study
Smith CE et al. Physical inactivity interacts with an endothelial lipase polymorphism to modulate high density lipoprotein cholesterol in the GOLDN study. Atherosclerosis, 2009, a community-based family study of 1,123 White adults. Participants with the TT genotype who logged high daily screen time (≥2.6 hours) showed lower total HDL-C, reduced large HDL particle concentrations, smaller HDL particle sizes, and elevated small LDL concentrations compared to CT and CC carriers at the same activity level. The effect reached statistical significance (P<0.05) across multiple HDL measures and was more pronounced in women than men.

Halverstadt et al.³³ Halverstadt et al.
Halverstadt A et al. High-density lipoprotein-cholesterol, its subfractions, and responses to exercise training are dependent on endothelial lipase genotype. Metabolism, 2003 studied 83 sedentary adults aged 50–75 who underwent aerobic exercise training. At baseline, CT/TT carriers showed lower HDL(2NMR)-C (12±1.0 vs 17±1.1 mg/dL, P=.002) and lower integrated HDL subfractions. After training, CC homozygotes gained 4.4 mg/dL HDL-C versus only 1.9 mg/dL in CT/TT carriers (P=.04), indicating that the T allele also blunts the HDL response to aerobic exercise.

Vergeer et al.⁴⁴ Vergeer et al.
Vergeer M et al. Lack of association between common genetic variation in endothelial lipase (LIPG) and the risk for CAD and DVT. Atherosclerosis, 2010 examined rs6507931 in relation to coronary artery disease and deep vein thrombosis. While an initial DVT association (OR 2.04) appeared in one cohort, it could not be replicated, confirming this variant is best classified as a modifier of HDL metabolism rather than a direct cardiovascular risk allele under all conditions.

Practical Actions

The clearest actionable implication of the T allele is that regular aerobic activity is especially important for maintaining HDL-C and HDL particle quality. Exercise suppresses LIPG expression in skeletal and cardiac muscle — T allele carriers who remain sedentary lose this protective downregulation and experience greater HDL degradation. Specifically, high-intensity aerobic activity (cycling, running, swimming) at ≥150 minutes per week has been shown to elevate HDL-C and HDL particle size in LIPG-variant carriers. Omega-3 fatty acids (EPA/DHA) support HDL particle remodeling through a complementary mechanism independent of LIPG activity.

Monitoring the fasting lipid panel — specifically HDL-C and ideally HDL particle size via NMR lipoprotein analysis — provides the most informative tracking for TT individuals, because total HDL-C alone may underestimate the shift toward smaller, less cardioprotective HDL particles.

Interactions

The coding variant rs2000813 (Thr111Ile, T111I) in LIPG exon 3 is the most studied functional variant in this gene and affects EL enzyme activity directly. Carriers of the rs2000813 minor allele (Ile111) show modest HDL-C elevation. rs6507931 and rs2000813 are in linkage disequilibrium in some populations and were studied together in the Hutter et al. haplotype analysis of Japanese Americans (PMID 16023652). The combined haplotype effect on HDL subfractions and apolipoprotein AI levels exceeded either variant alone.