Human Genetics and the Causal Role of Lipoprotein(a) for Various Diseases

If you want to know whether something truly causes disease rather than merely traveling with it, genetics is the cleanest court — and by that standard, this review establishes Lp(a) as arguably the most important inherited cardiovascular risk factor we have.

The author synthesizes the genetic architecture: Lp(a) levels vary more than a thousand-fold between people and are over 90% set by the LPA gene, with the number of “KIV-2” repeats and small protein isoforms driving high levels. Mendelian randomization then does the heavy lifting — proving Lp(a) causes coronary disease and aortic valve stenosis, while notably ruling out a causal role in venous clots (despite Lp(a)‘s clot-inhibiting behavior in the test tube) and even suggesting an inverse link with type 2 diabetes. A crucial practical warning: the common SNP tests on the market miss roughly half of high-risk people with small isoforms.

The practical takeaway is that Lp(a) is causal, not just correlated — measure it directly rather than relying on limited genotype tests, and recognize that lowering it is unlikely to raise diabetes risk at therapeutic levels.

We rate the evidence high: a definitive synthesis of genetic and Mendelian-randomization data by a foundational expert, fair about its limits. Its clinical significance is high — it shaped how the field thinks about Lp(a) testing and set the stage for the targeted therapies now in trials.