ANGPTL4 E40K — The Triglyceride-Lowering Variant
Angiopoietin-like protein 4 (ANGPTL411 ANGPTL4
a secreted protein that normally
shuts off lipoprotein lipase, the enzyme responsible for clearing
triglycerides from the bloodstream) acts as a brake on fat clearance.
The E40K variant at rs116843064 partially disables this brake. Carriers of
the K40 allele (the minor A allele) have less ANGPTL4-mediated LPL
inhibition, leading to faster triglyceride clearance after meals and
persistently lower fasting triglyceride levels throughout life. This is one
of a small number of naturally occurring human variants in the ANGPTL
family with a clearly protective cardiovascular phenotype.
The Mechanism
ANGPTL4 is secreted from the liver and adipose tissue and inhibits
lipoprotein lipase (LPL)22 lipoprotein lipase (LPL)
the enzyme anchored to capillary walls that
hydrolyzes triglycerides in VLDL and chylomicrons, releasing fatty acids
for tissue uptake by promoting its dissociation from the capillary wall.
The E40K substitution (p.Glu40Lys) alters the N-terminal coiled-coil
domain of ANGPTL4, reducing its inhibitory potency against LPL. With less
ANGPTL4-mediated inhibition, LPL remains more active — it clears more
triglyceride-rich lipoproteins from circulation, leaving lower fasting and
postprandial TG levels. This variant is classified as a partial
loss-of-function: it reduces, but does not abolish, ANGPTL4 activity,
distinguishing it from complete LOF mutations.
The Evidence
The most definitive evidence comes from two large-scale genetic studies.
The 2016 NEJM paper from the MI Genetics and CARDIoGRAM Exome Consortia33 2016 NEJM paper from the MI Genetics and CARDIoGRAM Exome Consortia
Myocardial Infarction Genetics and CARDIoGRAM Exome Consortia. Coding
Variation in ANGPTL4, LPL, and SVEP1 and the Risk of Coronary Disease.
NEJM, 2016 analyzed 72,868
CAD cases and 120,770 controls and found the E40K variant specifically
associated with a 14% reduced odds of coronary artery disease
(OR 0.86, P=4.0×10⁻⁸). Complete LOF mutations in ANGPTL4 in the same
study produced even larger effects (OR 0.47 for MI, and 35% lower
triglyceride levels in carriers).
A 2024 phenome-wide analysis by Gagnon et al.44 Gagnon et al.
Gagnon E et al. Impact of
loss-of-function in angiopoietin-like 4 on the human phenome. Atherosclerosis,
2024 used FinnGen (309,154
participants) and UK Biobank whole-exome data (488,278 participants) to
confirm the E40K signal: OR 0.84 for CAD (P=3.6×10⁻²¹) and OR 0.91 for
type 2 diabetes (P=2.8×10⁻⁵). Critically, a phenome-wide scan of 1,589
diseases found no significant risk increases attributable to E40K — the
variant does not appear to trade cardiovascular benefit for harm elsewhere.
Triglyceride reductions are well-quantified across multiple cohorts.
Talmud et al.55 Talmud et al.
Talmud PJ et al. ANGPTL4 E40K and T266M: effects on
plasma triglyceride and HDL levels, postprandial responses, and CHD risk.
Arterioscler Thromb Vasc Biol, 2008
pooled 5 cohorts (n=13,527) and found K40 carriers had 20.4% lower fasting
triglycerides (P<0.0001). In the Look AHEAD trial of 2,601 adults with type 2
diabetes, Smart-Halajko et al.66 Smart-Halajko et al.
Smart-Halajko MC et al. ANGPTL4 variants
E40K and T266M are associated with lower fasting triglyceride levels in
Non-Hispanic White Americans from the Look AHEAD Clinical Trial. BMC Med
Genet, 2011 found K40 carriers
had 0.33 mmol/L (~17%) lower TG than E40 homozygotes (P=0.001). Higher
HDL-cholesterol in K40 carriers has also been reported, consistent with the
reciprocal relationship between TG clearance and HDL-C levels.
The evidence is rated strong: consistent replication across large
independent cohorts, a clear molecular mechanism via LPL de-inhibition,
genome-wide significant association with hard cardiovascular outcomes, and
phenome-wide safety data. It falls short of established because ANGPTL4
genotyping is not yet incorporated into clinical lipid management guidelines.
Practical Actions
For the rare individual carrying one or two A alleles, the E40K variant provides a durable biological advantage in TG metabolism. Dietary fat composition still matters: while overall TG clearance is enhanced, the variant does not override the acute postprandial TG spike from very high saturated fat loads. Omega-3 fatty acid supplementation (EPA/DHA) works through a partially overlapping pathway — both E40K and high-dose omega-3s reduce VLDL-TG — so carriers may derive additive benefit from omega-3 intake if baseline TG is in the borderline range.
Because triglyceride levels influence remnant lipoprotein particle burden and are an independent cardiovascular risk factor, the 17–20% TG reduction from E40K is clinically meaningful and worth monitoring through standard lipid panels to confirm phenotypic expression.
Interactions
ANGPTL4 E40K operates in the same triglyceride-clearance pathway as APOA5 (rs3135506), which also modulates LPL activity. A carrier of both E40K and the APOA5 S19W variant (which raises TG) might see partially opposing effects — the combined phenotype would depend on effect magnitudes at each locus. Similarly, the APOC3 promoter variants (rs2854116) that elevate ApoC-III and inhibit LPL are in the same downstream pathway: carrying ANGPTL4 E40K alongside an APOC3 TG-raising variant would likely attenuate but not fully overcome the APOC3 effect. No formal published compound analysis exists for these specific genotype combinations, so these remain pathway-level interactions rather than quantified compound effects.
The companion ANGPTL4 variant T266M (rs1044250) has an independent but weaker TG-lowering effect (~10% reduction) and operates through a different structural domain of the protein. Carriers of both E40K and T266M may have additive TG lowering, though compound heterozygosity at these two positions is rare.