The purpose of this study is to determine whether fish oil supplementation is effective in the treatment of abnormal fat metabolism in subjects with elevated cholesterolaemia.

The use of statin therapy in familial hypercholesterolaemia (FH) is known to reduce cardiovascular risk and is a first line recommendation, however, there is considerable residual risk predicted by the presence of fasting and post-prandial hypertriglyceridaemia.

This study will examine the effect of oral n-3 fatty acid ethyl esters supplementation (4g/day, Omacor) on postprandial hypertriglyceridaemia and post-prandial arterial function when administrated to FH patients at increased risk of cardiovascular disease due to their residual fasting hypertriglyceridaemia.

Inclusion Criteria:

• Patients with FH (genetically defined LDL-receptor mutation or Dutch score >8) on statin treatment only
• Hypertriglyceridaemia on a random blood sample (triglycerides >1.5mml/L)

Exclusion Criteria:

• Subjects with diabetes mellitus
• major systemic illness or use of steroids or other lipid-regulating drugs (such as niacin, fibrate and colesevelam)
• patients on hypocaloric diets or LDL apheresis; anaemia, haemorrhage and pregnancy.