Families of early heart attack victims to be offered lab tests

The UK National Institute for Health and Clinical Excellence (NICE) published online guidance for ‘The identification and management of familial hypercholesterolaemia’on 29 August 2008. Familial hypercholesterolaemia (FH) is caused by an inherited problem with the removal of low-density lipoprotein (LDL) from the blood. The abnormality is passed on in such a way that the children (and the brothers and sisters) of an affected person have a 50% chance of having FH. The commonest cause is a mutation of the cell surface receptor for LDL. This and most of the other less common mutations can be identified with DNA-based lab tests.

If FH is not treated there is a greater than 50% risk that a man will have coronary heart disease by the age of 50 and a more than 30% risk that a woman will have heart disease by the age of 60. The condition is estimated to be present in 1 in 500 of the UK population, so that some 120,000 people are affected. However only about 15% have been identified, leaving tens of thousands undiagnosed.

NICE recommends that the diagnosis be considered in adults with a total cholesterol greater than 7.5 mmol/L (in those under 16, greater than 6.7 mmol/L) and either a family history of a heart attack in a blood relative aged less than 60 or a family history of similarly raised cholesterol levels. (Other causes of raised cholesterol values such as diabetes or reduced thyroid function should be excluded.) The diagnosis is confirmed if LDL-cholesterol values are greater than 4.9 mmol/L in an adult or 4.0 mmol/L in those under 16 and they have tendon xanthomas (yellow fat-filled lumps) or a positive DNA lab test.

NICE recommends referral of people with FH to a specialist to initiate testing of all blood relatives using LDL-cholesterol and DNA tests. Children of an affected parent should have, by the age of 10 or as soon as possible afterwards, measurements of LDL-cholesterol or a DNA test if the parent’s test was positive.
All those found to have FH should be considered for treatment with cholesterol-lowering drugs (statins) and given advice on smoking, diet and exercise.

Dr Gillian Leng, executive lead for the guidance and deputy chief executive of NICE, said: "Familial hypercholesterolaemia is a serious often undiagnosed but relatively common condition which if treated early will not affect normal life expectancy for the majority of people with the condition.