Familial hypercholesterolemia or FH is an inherited defect in how the body recycles LDL (bad) cholesterol. As a consequence, LDL levels in the blood remain very high – in untreated adults, above 190 milligrams per deciliter (mg/dL) of blood. People with FH are essentially born with high LDL cholesterol. Everyone’s cholesterol levels tend to rise with age. But those with FH have LDL levels that start high and go even higher over time.