Module 4
A few cardiovascular conditions are inherited, which means a finding in one relative is information for blood relatives too. Knowing the names makes it possible to ask about them.
FH is an inherited condition that raises cholesterol from early in life. The CDC’s Office of Genomics reports studies estimating a prevalence of about 1 in 250 people in the general population. CDC has also stated that of the more than 1 million people in the United States with FH, only about 30% know they have it.
The American Heart Association describes HCM as most often caused by abnormal genes that thicken the wall of the heart’s left ventricle, and as a common form of genetic heart disease. The AHA states that HCM has been regarded as the most common cause of sudden cardiac death in young people and competitive athletes in North America, while also noting that it is rare. The NHLBI notes that HCM is commonly inherited and that first-degree relatives should be alerted and screened.
Lp(a) is measured by a separate blood test that a routine lipid panel does not include. The American College of Cardiology’s summary of the 2026 multisociety dyslipidemia guideline states that Lp(a) should be measured at least once in adulthood, and notes that because lifestyle changes affect Lp(a) minimally, repeat testing is generally not needed.
MedlinePlus describes apolipoprotein B100 as a protein involved in moving cholesterol around the body, and the test as one used to help identify the cause or type of high cholesterol. Like Lp(a), it is ordered separately from a routine panel. Whether either test fits a particular person is a clinical decision.
The 2019 ACC/AHA primary prevention guideline lists family history of premature atherosclerotic cardiovascular disease as a risk-enhancing factor, defining premature as before age 55 in males and before age 65 in females. Separately, GeneReviews notes that in long QT syndrome most sudden cardiac deaths occur during exercise such as swimming or during emotion, and that in an estimated 10% to 15% of people who die of long QT complications, death is the first sign of the disorder. An unexplained drowning or near-drowning in a relative is therefore worth mentioning to a clinician rather than treating as unrelated.
A pattern is context that helps a qualified clinician decide which questions and measurements are worth discussing. It does not diagnose anyone, and this page does not calculate anything about the reader.
Sources and limitations
This page restates published public-health guidance and was checked against its sources on 2026-07-14. Independent clinician review in progress.
Legacy Heart Health Initiative is a cardiovascular health, prevention, and early-action program in development. This page is not medical advice and does not replace a qualified clinician. If you may be experiencing an emergency, contact local emergency services rather than using this site.
