What are the symptoms? The most serious complication of hypertriglyceridaemia is acute pancreatitis. This occurs when the pancreas becomes inflamed and releases digestive enzymes into the abdomen causing damage. Pancreatitis causes very severe abdominal pain and can be life-threatening. Many people with hypertriglyceridaemia experience abdominal pain because of long term inflammation of the pancreas. The liver and spleen may be enlarged and there may be fatty lumps in the skin (called eruptive xanthomas) often round the elbows and knees. What are the causes? Hypertriglyceridaemia with excessive chylomicrons in the blood is usually a genetic disease. There may be an inherited deficiency of the enzyme lipoprotein lipase caused by mutation in the LPL gene, or more rarely of the protein apo C-II caused by mutations in the APOC2 gene. These disorders are very rare, affecting about 1 in every one million people in the UK, although more people from Asia are affected. How is it diagnosed? Hypertriglyceridaemia is diagnosed by a blood test to measure triglyceride levels. Special blood tests can be used to measure lipoprotein lipase and apo C-II levels, or genetic testing may be used to find the gene defect. Some children are diagnosed when they have a blood tests and their blood plasma looks abnormally creamy. How is it treated? Treatment is aimed at lowering blood triglycerides to a safe level. A very low fat diet is the main part of treatment. This should be supervised by an experienced dietician. Special fats called medium chain triglycerides (MCT) can be used in infant formulas or as dietary supplements to provide energy and MCT may help to reduce triglyceride levels. Fat soluble vitamins and essential fatty acids (often as walnut oil) should be given as supplements. Inheritance patterns and prenatal diagnosis Inheritance patternsLipoprotein lipase and apo C-II deficiencies are recessively inherited – both parents carry one copy of a mutant LPL or APOC2 gene, and the affected child inherits the mutated gene from each unaffected carrier parent. Prenatal diagnosisPrenatal diagnosis is possible if the gene mutation is known, although it is rarely requested as effective treatment is available. Is there support? Information and support in the UK for organic acidaemias is provided by Metabolic Support UK (see entry Inherited Metabolic diseases).