GPs have key role in detecting familial hypercholesterolaemia

Currently the vast majority of people with familial hypercholesterolaemia (FH) in the U.K. remain undiagnosed, probably 85% of the predicted 120,000 cases. FH is a common inherited disorder of lipid metabolism causing high levels of LDL cholesterol which leads to early CHD. It has an autosomal dominant pattern of inheritance so siblings and children of a patient with FH will have a 50% chance of inheriting the condition. FH is present in the heterozygous form in 1 in 500 of the population. The homozygous form is very rare, affecting 1 in 1,000,000. Around half of men with FH, if untreated, will have developed clinically evident CHD by the age of 55 years, and approximately one third of women by the age of 60. A significant reduction in the mortality and morbidity of the disease can be achieved through changes in lifestyle and the use of statins to lower cholesterol. NICE recommends that clinical management of FH patients should primarily be carried out in lipid clinics. When cascade testing from lipid clinics is underway, GPs will be approached by relatives who have been identified as being at 50% risk of having FH, because they have an affected first-degree relative with the disorder. They will then need to take a blood sample for cholesterol measurement, and often will also be asked to provide a sample for DNA testing. A preliminary investigation in the surgery of a family member would involve a full lipid profile to calculate LDL cholesterol. If this is not elevated in an adult, cut-off value 4.9 mmol/L, FH is highly unlikely. Even if an FH patient is young, currently does not have CHD and may have no other CHD risk factors, the Framingham risk charts should not be used. These individuals are at increased CHD risk which warrants treatment with statins. The vascular health check screening programme recommends that where a total cholesterol of > 7.5 mmol/L is found FH should be considered.