Sequence variations in PCSK9, low LDL, and protection against coronary heart disease.
Level 3 - non-randomized controlled study
Prospective cohort study evaluating outcomes over a 15-year follow-up interval.
PubMed 16554528 · doi:10.1056/NEJMoa054013
What was done
Researchers analyzed the relationship between DNA-sequence variations in the PCSK9 gene that lower plasma LDL cholesterol and the 15-year incidence of coronary heart disease (myocardial infarction, fatal CHD, or coronary revascularization) in 3,363 Black subjects and 9,524 White subjects from the Atherosclerosis Risk in Communities study.
What was found
Among Black subjects, 2.6% had PCSK9 nonsense mutations associated with a 28% reduction in mean LDL cholesterol and an 88% reduction in CHD risk (hazard ratio, 0.11; 95% confidence interval, 0.02 to 0.81; P=0.03; P=0.008 for cholesterol reduction). Among White subjects, 3.2% had a PCSK9 sequence variation associated with a 15% reduction in LDL cholesterol and a 47% reduction in CHD risk (hazard ratio, 0.50; 95% confidence interval, 0.32 to 0.79; P=0.003).
Why it matters
This study shows that lifelong, genetically mediated reductions in LDL cholesterol yield substantial reductions in coronary event rates, validating PCSK9 as a critical regulator of cardiovascular risk.
Limits
The examined mutations were rare (2.6% and 3.2%), resulting in wide confidence intervals, particularly in the Black cohort. The observational design reflects lifelong exposure rather than adult-initiated pharmacological intervention, and potential confounding variables or non-lipid risk factor adjustments are not detailed in the abstract.
Cited by
- supports Dr. Helen Hobbs discovered in the early to mid-2000s that individuals with loss-of-function/hypofunctioning mutations in the PCSK9 gene have LDL cholesterol levels around 10 to 20 mg/dL and are protected against cardiovascular disease.