Familial hyper-cholesterolaemia (FH) is a relatively common genetic disorder. The heterozygous form affects 1 in 500 people in the UK, i.e. 0.2% of the population. However, the vast majority of patients remain undiagnosed. FH is a risk factor for the development of premature atherogenesis. All first-degree relatives, not just the children, of FH patients have a 50% risk of having the condition; and should be traced and tested, a process known as cascade testing. Until such services become widely available, the BHF has recommended that, relatives of a patient with FH should be advised to visit their GP to be evaluated and, preferably, referred for a DNA test.