Final answer:
Familial hypercholesterolemia is characterized by high levels of LDL cholesterol and increased risk of premature cardiovascular disease, often caused by mutations in the LDL receptor or ApoB genes.
Step-by-step explanation:
Familial hypercholesterolemia is characterized by high levels of cholesterol in the blood, specifically elevated levels of low-density lipoprotein (LDL). This condition is often due to a genetic mutation in the LDL receptor gene on chromosome 19 or the ApoB gene. Individuals with this condition may present with tendon xanthomas, xanthelasma, and an increased risk of premature cardiovascular disease. Familial hypercholesterolemia is a subset of hyperlipoproteinemia type IIa and is associated with hyperbetalipoproteinemia, which results in increased plasma total cholesterol levels. Cases that are not linked to genetic causes may be sporadic due to dietary factors or polygenic.