rs2854117 — APOC3 APOC3 C-482T

Promoter variant in APOC3 disrupting insulin-responsive regulation of apolipoprotein C-III, raising triglycerides and VLDL through impaired post-meal suppression of apoCIII secretion

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APOC3 C-482T — When Your Body Can't Turn Off the Fat Signal

Apolipoprotein C-III (apoCIII) is the body's master brake on triglyceride clearance. It coats triglyceride-rich VLDL particles and inhibits the lipoprotein lipase11 lipoprotein lipase
The enzyme that breaks down triglycerides in blood, releasing fatty acids for tissues that would otherwise clear them. After a meal, healthy physiology suppresses apoCIII secretion — letting triglycerides clear quickly. The rs2854117 variant disrupts that suppression, keeping apoCIII elevated and triglycerides circulating longer.

The Mechanism

The APOC3 gene sits on chromosome 11 in a cluster with APOA1, APOA4, and APOA5. Its promoter contains a negative insulin response element (nIRE)22 negative insulin response element (nIRE)
A DNA sequence where insulin binding normally represses gene transcription that ordinarily drives down APOC3 output after eating. The C-482T variant (T allele at rs2854117) lies within this nIRE, altering its sequence and blunting the insulin signal that should silence APOC3. The result is persistently elevated apoCIII protein, which keeps VLDL particles circulating and slows triglyceride clearance from the bloodstream.

The -482 position is in strong linkage disequilibrium with rs2854116 (T-455C), and the two variants are usually studied together as part of an APOC3 promoter haplotype. Both sit within the same nIRE, and their combined effect on insulin-mediated suppression appears additive.

The Evidence

A 2003 prospective cohort study in 502 adults33 2003 prospective cohort study in 502 adults
Waterworth et al. Variants in the APOC3 promoter insulin responsive element modulate insulin secretion and lipids. Arteriosclerosis, Thrombosis, and Vascular Biology, 2003 found that T allele homozygotes had a 33% lower 30-minute insulin increment after glucose challenge, and approximately 10% higher non-esterified fatty acid (NEFA) levels, compared to CC homozygotes. Both variants (at -482 and -455) also interacted with smoking to worsen fasting triglycerides.

A 2001 epidemiological study in 983 French adults44 2001 epidemiological study in 983 French adults
Dallongeville et al. Polymorphisms in the insulin response element of APOC-III gene promoter influence the correlation between insulin and triglycerides. Arteriosclerosis, Thrombosis, and Vascular Biology, 2001 confirmed that the -482 T allele modifies the relationship between plasma insulin and triglyceride-rich LpCIII:B particles, particularly in women.

The most direct disease-risk evidence comes from a 2025 Chinese case-control study in 440 participants55 2025 Chinese case-control study in 440 participants
Ye et al. Associations between APOC3 and ANGPTL8 gene polymorphisms with MASLD risk. 2025, which found that CT+TT carriers had 1.9-fold higher odds of metabolic dysfunction-associated steatotic liver disease (MASLD) compared with CC carriers (OR 1.9, 95% CI 1.2–3.2), with triglycerides mediating 62.6% of that genetic effect.

Pharmacogenomic data from the GOLDN trial66 GOLDN trial
Liu et al. Pharmacogenetic association of the APOA1/C3/A4/A5 gene cluster and lipid responses to fenofibrate. Pharmacogenetics and Genomics, 2009 showed that the T minor allele is associated with a blunted triglyceride-lowering response to fenofibrate (p=0.026), unlike other variants in the same cluster which enhance the response. This suggests the -482 variant alters the transcriptional pathway fenofibrate relies on.

Evidence is mixed on broader cardiovascular endpoints: a meta-analysis found no significant association with ischemic stroke77 found no significant association with ischemic stroke
Zhang et al. The impact of APOA5, APOB, APOC3 and ABCA1 gene polymorphisms on ischemic stroke. Gene, 2017, and studies in European cohorts have not consistently shown a NAFLD/liver-fat association, suggesting ethnic and dietary context modulate the phenotypic expression.

Practical Actions

T allele carriers should focus on the two levers most directly linked to apoCIII activity: dietary fat quality and post-meal triglyceride clearance. Limiting refined carbohydrates and fructose is particularly relevant because both raise apoCIII transcription independently of the promoter variant. Long-chain omega-3 fatty acids (EPA and DHA) suppress apoCIII at the transcriptional level, partially compensating for the blunted insulin signal.

Fasting triglyceride testing is the most direct way to track phenotypic expression of this variant. Levels consistently above 150 mg/dL suggest the variant is having a meaningful effect and warrant dietary intervention. Fenofibrate may have a reduced effect in T carriers; if fibrate therapy is being considered, this variant is worth noting to the prescribing clinician.

Interactions

rs2854117 is in strong linkage disequilibrium with rs2854116 (T-455C, the other APOC3 promoter nIRE variant). Carriers of the T allele at rs2854117 are very likely to also carry the C allele at rs2854116. Studies generally show additive effects on apoCIII dysregulation when both promoter variants are co-inherited. The APOC3 3'-SstI variant (rs5128) operates through a different mechanism (post-transcriptional or 3'-regulatory) and has independent effects on VLDL — its effect can stack with the promoter haplotype.

The APOA5 rs662799 variant is a frequent companion in hypertriglyceridemia genetic panels and encodes a different step in the VLDL-triglyceride axis. When rs662799 risk allele co-occurs with the rs2854117 T allele, the combined triglyceride burden is likely additive, though published compound analyses are limited.

Drug Interactions

fenofibrate reduced_efficacy literature

Nutrient Interactions

saturated fat altered_metabolism
omega-3 fatty acids increased_need

Genotype Interpretations

What each possible genotype means for this variant.

CC Normal apoCIII Regulation Normal

Standard insulin-driven apoCIII suppression after meals

The CC genotype preserves the normal sequence of the APOC3 negative insulin response element (nIRE). After a carbohydrate-containing meal, rising insulin levels bind to the nIRE and suppress APOC3 transcription, reducing apoCIII protein output. With less apoCIII coating VLDL particles, lipoprotein lipase can efficiently hydrolyze triglycerides and clear VLDL from circulation. Fasting triglycerides in CC individuals tend to be in the normal range in the absence of other metabolic stressors.

CT Partial apoCIII Dysregulation Intermediate

One risk copy — mildly impaired post-meal apoCIII suppression

The CT genotype creates a semi-functional insulin response element. The C-bearing copy of APOC3 still suppresses normally in response to insulin, but the T-bearing copy produces persistent low-level apoCIII output regardless of insulin status. In practice, this means post-meal triglyceride peaks are somewhat higher and take longer to clear. The Waterworth et al. 2003 study (n=502) found intermediate phenotypes in heterozygotes — elevated NEFA levels were observed, though the 33% reduction in insulin increment was specific to TT homozygotes. The MASLD odds elevation (OR 1.9) was observed for CT+TT combined, suggesting even one T allele confers meaningful risk. Smoking and high refined-carbohydrate intake amplify the phenotypic effect in heterozygotes.

TT Full apoCIII Dysregulation High Risk

Two risk copies — impaired post-meal triglyceride clearance

TT homozygotes have essentially no functional insulin-suppressible apoCIII regulation at this promoter position. The Waterworth et al. 2003 Ely cohort study found TT homozygotes had 33% lower 30-minute insulin incremental response and ~10% higher non-esterified fatty acid (NEFA) levels compared to CC homozygotes. This NEFA elevation feeds back into hepatic triglyceride synthesis, creating a secondary driver of hypertriglyceridemia beyond the direct apoCIII effect. The 2025 Chinese case-control study found CT+TT carriers had 1.9-fold elevated odds of MASLD vs CC (OR 1.9, CI 1.2–3.2), with triglycerides mediating 62.6% of that risk pathway.

Pharmacogenomics are relevant: in the GOLDN fenofibrate trial, the T minor allele was associated with a blunted triglyceride-lowering response to fenofibrate (p=0.026), unlike most other variants in the APOA1/C3/A4/A5 cluster. TT carriers considering fibrate therapy should inform their prescriber, as dose optimization or alternative agents (niacin, high-dose omega-3) may be more appropriate.

Smoking worsens the triglyceride phenotype in T allele carriers across sexes (Waterworth 2003), and high fructose intake amplifies the apoCIII transcriptional driver through an insulin-independent pathway. The TT genotype warrants more aggressive metabolic monitoring and dietary management.