rs13236689 — CD36

CD36 rs13236689 — Fat Sensing, Platelet Activation, and Cardiovascular Risk

CD36 (also called fatty acid translocase, or FAT) is one of the body's key gatekeepers for dietary fat. It sits on the surface of cells throughout the intestine, tongue taste buds, platelets, macrophages, muscle, and adipose tissue. Its job is to bind long-chain fatty acids — the molecules that make up most of the fat in food — and shuttle them into cells. When CD36 expression is higher, cells take up more fat; when it is lower, fat stays in the bloodstream longer. rs13236689 is an intronic variant¹¹ intronic variant
A variant within a non-coding intron of the CD36 gene; these often act as expression regulators by altering transcription factor binding sites in the surrounding DNA that modulates how much CD36 protein cells produce.

The Mechanism

rs13236689 does not change the CD36 protein sequence — it lies within an intron on chromosome 7 at position 80,606,698 (GRCh38). Its biological significance lies in its status as a platelet expression quantitative trait locus (eQTL)²² platelet expression quantitative trait locus (eQTL)
An eQTL is a genomic variant that explains variation in how much of a gene's mRNA — and ultimately protein — is produced in a given tissue. Carriers of the G allele are in strong linkage disequilibrium with the functional regulatory variants rs2366739 and rs1194196, which sit approximately 13–55 kb upstream of the CD36 transcriptional start site and alter transcription factor binding. When these regulatory variants are active, platelet CD36 mRNA and surface protein levels increase. Higher platelet CD36 means stronger responses to oxidized LDL (oxLDL) — the chemically modified form of cholesterol that accumulates in atherosclerotic plaques — and greater platelet activation in lipid-rich environments.

The metabolic consequences extend beyond platelets. In the gut, enterocyte CD36 expression levels determine how efficiently long-chain fatty acids trigger satiety signals: CD36 converts dietary fatty acids into oleoylethanolamide (OEA)³³ oleoylethanolamide (OEA)
A bioactive lipid that activates PPARα in the gut wall, sending a sustained satiety signal to the brain via the vagus nerve, which in turn activates PPARα to prolong the feeling of fullness after a fat-rich meal. Variants that push CD36 expression higher also increase uptake of oxLDL by macrophages in artery walls — a key step in foam cell formation and atherosclerosis.

The Evidence

The primary genetic evidence for rs13236689 comes from the COGENT consortium meta-analysis⁴⁴ COGENT consortium meta-analysis
Cheng et al. (2012), PLoS Genetics — a meta-analysis of 7 genome-wide association studies in over 16,000 African Americans from population-based cohorts, which identified rs13236689 as a genome-wide significant locus for platelet count (p = 2.84×10⁻⁹; β = +4.18 × 10⁹ platelets/L per G allele). The association nominally replicated in European Americans. The same variant was subsequently shown by Madan et al. (2019, PLoS Genetics)⁵⁵ Madan et al. (2019, PLoS Genetics)
Using a massively parallel reporter assay to screen 81 CD36 eQTLs, the authors confirmed that rs13236689 is a bona fide eQTL for platelet CD36 mRNA, with the causal signal mapping to two nearby regulatory variants (rs2366739, rs1194196) in high LD to be a platelet CD36 eQTL: G allele carriers have higher platelet CD36 surface expression.

The downstream cardiovascular significance of CD36 expression variation is well-established: higher platelet CD36 augments oxLDL-induced platelet activation and has been associated with thromboembolism risk. At the gene level, Love-Gregory et al. (2008)⁶⁶ Love-Gregory et al. (2008)
Population study of 2,020 African Americans from the HyperGEN cohort; PMID 18305138 showed that multiple CD36 variants modulate HDL-C, triglycerides, and metabolic syndrome risk. The CD36 AGGIG haplotype in Caucasians was associated with 31% higher free fatty acids and OR 2.3 for cardiovascular events in type 2 diabetics (Corpeleijn et al. 2006, PMID 15282206)⁷⁷ (Corpeleijn et al. 2006, PMID 15282206).

Evidence for rs13236689's direct effect on dietary fat handling and plasma lipids is moderate — the lipid associations are inferred from the eQTL relationship and the well-established biology of CD36 expression, rather than from dedicated dietary intervention trials targeting this specific variant.

Practical Actions

Because rs13236689 G allele carriers have higher platelet CD36 expression, they are likely to mount stronger platelet responses to circulating oxidized LDL. This is most relevant in the context of a diet high in saturated and trans fats, which drive oxLDL production. Limiting foods that generate oxLDL — principally processed and ultra-processed foods containing oxidized vegetable oils and trans fats — is directly relevant to this genotype. Longer-chain omega-3 fatty acids (EPA/DHA) compete with pro-inflammatory fatty acids at the CD36 binding site and have been shown to reduce platelet activation. Monitoring fasting triglycerides and HDL-C provides a practical window into CD36-mediated fat metabolism; the CD36 eQTL mechanism links directly to postprandial lipemia.

Interactions

rs13236689 is in linkage disequilibrium with other CD36 expression-regulating variants. The most studied CD36 SNP, rs1761667 (promoter, −31118G>A), directly affects fat taste sensitivity — AA homozygotes have 8-fold higher detection thresholds for oleic acid, meaning they perceive fat less intensely and tend to eat more of it. If a person carries both rs13236689 G (higher CD36 in platelets/ macrophages) and rs1761667 AA (lower fat taste sensitivity from reduced tongue CD36), the combined effect — increased cardiovascular risk from platelet hyperactivation alongside blunted dietary fat sensing — warrants attention. rs3211938 is a CD36 truncation variant (stop-gain) that dramatically reduces CD36 protein; this variant is functionally distinct from rs13236689 and largely confined to African-ancestry populations.