Cascade testing

A mechanism for identifying people at risk of a genetic condition by a process of family tracing. Relatives of the individual diagnosed with familial hypercholesterolaemia are tested for the condition, as are their relatives; ideally, cascade testing should be undertaken in first-, second- and third-degree relatives. For familial hypercholesterolaemia the test employed is measurement of (low-density lipoprotein) cholesterol in the blood and/or a DNA test if a disease-causing mutation has been identified in the proband/index.