Yes, this is well established in medical literature. The clearest example is familial hypercholesterolemia, an inherited condition caused by changes in specific genes involved in how the body clears low-density lipoprotein cholesterol from the blood. The genes most commonly involved are LDLR, APOB, and PCSK9. A change in any one of these genes can prevent the liver from removing low-density lipoprotein cholesterol efficiently, leading to very high cholesterol levels from birth, well before diet or lifestyle factors come into play. Familial hypercholesterolemia follows a clear inheritance pattern within families, and children of an affected parent have a fifty percent chance of inheriting the same gene change. Beyond this single-gene form, research has also identified many common genetic variations that each contribute a small effect, together explaining why cholesterol levels tend to run in families even without a single identifiable gene change. So genetic contribution to high cholesterol is not a theory; it is a confirmed and well-studied mechanism.