Molecular biological studies in familial hypercholesterolaemia have indicated that the severity of the disease, at least in terms of circulating LDL-cholesterol levels, varies depending on the kind of structural defect found in the LDL receptor gene. This may well influence individual risk and signal that more aggressive therapeutic intervention is required. The discovery of the statins has revolutionized therapy for the familial hypercholesterolaemia heterozygote, but the prognosis for the rare homozygote, who fails to respond adequately to therapy, remains poor unless extreme measures are taken.