People with a broken PCSK9 gene that lowers LDL cholesterol have a lower relative risk of coronary heart disease.
From We Are Witnessing The End of Heart Attacks · videoSee the scientific wording
In humans, carrying a loss-of-function ('broken') PCSK9 gene variant that lowers LDL cholesterol reduces the relative risk of coronary heart disease; the magnitude of the relative risk reduction and the absolute risk reduction are not reported.
Supported
Observational2 of 2 parts have evidence behind them.
Supported
2 of 2 parts have evidence behind them.
Parts of this claim
A broken PCSK9 gene lowers LDL cholesterol.
Supported3 studiesCarrying a broken PCSK9 gene reduces the relative risk of coronary heart disease.
Supported1 study
Evidence is judged against each part on its own, so a study that tests one part never counts as a verdict on the whole claim.
What the research says
3 studies reviewedSupporting (3)
Case-Control StudyHuman2014
The study found that people with a broken PCSK9 gene had lower LDL cholesterol and lower levels of a blood fat linked to heart disease risk. But it did not directly show that they actually had fewer heart attacks or heart disease events, so the claim is a bit stronger than the evidence.
PCSK9 genetic variants and risk of vascular and non-vascular diseases in Chinese and UK populations
Cohort StudyHuman2024
People with natural PCSK9 gene changes that lower cholesterol had lower risk of heart and blood vessel problems, so the claim is supported. The study looked at broad vascular events rather than only heart attacks.
PCSK9 genetic variants, carotid atherosclerosis and vascular remodelling
Cross-Sectional StudyMeta-analysis2025
The study found that people with certain PCSK9 gene changes have lower cholesterol and thinner artery walls, which is consistent with the idea that these gene changes lower heart disease risk. But the study did not actually count heart attacks, so it doesn't directly prove the heart disease risk reduction.
Contradicting (0)
No contradicting studies found yet
That doesn't mean it's settled — it just means no study has tested the opposite.
Quality-weighted scoring: we follow the GRADE framework — each study is rated High, Moderate, Low, or Very Low based on study design, methodology rigor, and risk of bias. A single high-quality RCT can outweigh several weaker observational studies.
Scores reflect study quality, not just count.
A broken PCSK9 gene makes less working PCSK9 protein. PCSK9 normally grabs the liver's LDL receptors and drags them to be destroyed. With less PCSK9, the liver keeps far more of these receptors on its surface. Those receptors pull LDL cholesterol out of the blood, so blood LDL cholesterol drops. Because less LDL cholesterol gets pushed into artery walls, fatty plaques grow more slowly and the artery wall stays thinner. Less plaque means fewer blockages, heart attacks, and strokes. A second benefit runs alongside this: the same change lowers blood fats called ceramides that make plaques weak and unstable, so the plaques that do form are less likely to rupture.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 3 supporting studies
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People with a broken PCSK9 gene that lowers LDL cholesterol have a lower relative risk of coronary heart disease.
Mechanism
3 studiesA broken PCSK9 gene means less PCSK9 protein is made. PCSK9 normally destroys the liver's LDL receptors, so with less of it the liver keeps more receptors that pull LDL cholesterol out of the blood. Lower LDL cholesterol means less fat gets packed into artery walls, so plaques grow more slowly and blockages that cause heart attacks and strokes happen less often. The same change also lowers blood fats called ceramides that make plaques weak, so plaques are steadier and less likely to burst.
A broken PCSK9 gene makes less working PCSK9 protein. PCSK9 normally grabs the liver's LDL receptors and drags them to be destroyed. With less PCSK9, the liver keeps far more of these receptors on its surface. Those receptors pull LDL cholesterol out of the blood, so blood LDL cholesterol drops. Because less LDL cholesterol gets pushed into artery walls, fatty plaques grow more slowly and the artery wall stays thinner. Less plaque means fewer blockages, heart attacks, and strokes. A second benefit runs alongside this: the same change lowers blood fats called ceramides that make plaques weak and unstable, so the plaques that do form are less likely to rupture.
A loss-of-function variant in the PCSK9 gene reduces the amount of functional PCSK9 protein produced, or disrupts the PCSK9 prodomain's binding to heparan sulfate proteoglycans, a step required for PCSK9 to function.
With less functional PCSK9, PCSK9-mediated lysosomal degradation of the hepatic LDL receptor is reduced, so LDL receptors are recycled back to the hepatocyte surface and their cell-surface availability increases.
The increased number of LDL receptors on hepatocytes enhances hepatic uptake and clearance of LDL cholesterol and apolipoprotein B from the bloodstream, lowering plasma LDL-C.
Lower circulating LDL-C reduces cholesterol deposition into the arterial wall, slowing atherosclerotic plaque growth and decreasing carotid intima-media thickness and carotid plaque burden.
Reduced atherosclerotic plaque burden lowers the occurrence of plaque rupture and thrombosis, decreasing the risk of major occlusive vascular events including coronary heart disease events and ischaemic stroke.
In parallel, the same targeted increase in hepatic LDL-receptor activity lowers circulating ceramides and glycosphingolipids; because these sphingolipids normally suppress macrophage apolipoprotein E production, impair cholesterol efflux, and drive foam-cell formation and plaque instability, their reduction stabilizes plaques and lowers the risk of fatal coronary events.
Less supported by current evidence, but not ruled out
The same broken PCSK9 gene that lowers cholesterol also raises the number of LDL and VLDL receptors on cells lining the lungs. Several respiratory viruses grab onto these receptors to get inside cells. With more receptors present, viruses enter lung cells more easily, so upper respiratory infections become more frequent, and these infections can set off flare-ups of lung diseases such as COPD and asthma. This is a separate, off-target effect of the same gene change and does not contribute to the lower heart disease risk.
PCSK9 binds to and mediates degradation of not only the LDL receptor but also the VLDL receptor, keeping their surface levels low.
Reduced PCSK9 activity raises LDL receptor and VLDL receptor levels in tissues including the lung.
Respiratory viruses bind to VLDL and LDL receptors on the surface of lung epithelial cells and are internalised by receptor-mediated endocytosis, initiating infection.
Higher availability of pulmonary LDL and VLDL receptors increases viral entry and the risk of upper respiratory tract infection, which triggers acute exacerbations of COPD and worsens asthma.
Evidence from Studies
Last searched 4d ago
Supporting (3)
Community contributions welcome
Molecular Lipids Identify Cardiovascular Risk and Are Efficiently Lowered by Simvastatin and PCSK9 Deficiency
The study found that people with a broken PCSK9 gene had lower LDL cholesterol and lower levels of a blood fat linked to heart disease risk. But it did not directly show that they actually had fewer heart attacks or heart disease events, so the claim is a bit stronger than the evidence.
PCSK9 genetic variants and risk of vascular and non-vascular diseases in Chinese and UK populations
People with natural PCSK9 gene changes that lower cholesterol had lower risk of heart and blood vessel problems, so the claim is supported. The study looked at broad vascular events rather than only heart attacks.
PCSK9 genetic variants, carotid atherosclerosis and vascular remodelling
The study found that people with certain PCSK9 gene changes have lower cholesterol and thinner artery walls, which is consistent with the idea that these gene changes lower heart disease risk. But the study did not actually count heart attacks, so it doesn't directly prove the heart disease risk reduction.
Contradicting (0)
Community contributions welcome
Score Breakdown
No multi-axis breakdown available yet. The overall Pro / Against score above is the best signal.
- No clinical evidence is available; the score reflects mechanistic plausibility only.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
Meta-Analysis of Mendelian Randomization Studies of PCSK9 Loss-of-Function Variants and Coronary Heart Disease
Systematic review and meta-analysis of prospective Mendelian randomization studies or large biobank cohorts; exposure: PCSK9 loss-of-function variants; comparator: non-carriers; outcome: coronary heart disease events; follow-up: lifetime or long-term; effect measure: relative risk and absolute risk difference if reported.
Randomized Controlled Trial of PCSK9 Inhibition vs Placebo for Coronary Heart Disease Events
Double-blind randomized controlled trial in adults with established or high-risk coronary heart disease; intervention: PCSK9 inhibitor vs placebo; outcome: major adverse cardiovascular events; duration: 2-5 years.
Prospective Cohort Study of PCSK9 Loss-of-Function Variant Carriers and Incident Coronary Heart Disease
Prospective cohort of adults genotyped for PCSK9 loss-of-function variants; compare carriers vs non-carriers; outcome: incident coronary heart disease; follow-up: 10+ years; adjust for confounders.
Case-Control Study of PCSK9 Loss-of-Function Variants in Coronary Heart Disease Cases
Coronary heart disease cases and matched controls genotyped for PCSK9 loss-of-function variants; outcome: odds ratio of coronary heart disease; retrospective design.
Cross-Sectional Study of PCSK9 Loss-of-Function Variants, LDL Cholesterol, and Coronary Heart Disease Prevalence
Cross-sectional survey of adults genotyped for PCSK9 loss-of-function variants; compare carriers vs non-carriers for LDL cholesterol and coronary heart disease prevalence.