Sitosterolemia: a new mutation in a Mediterranean patient

Sitosterolemia is a rare autosomal recessive disorder characterised by a high plasma level of sterols. A homozygous mutation or the compound heterozygous mutation in the ABCG5 gene or the ABCG8 gene leads to a complete loss of function of the ATP-binding cassette (ABC) heterodimer transporter G5-G8, which is localised to the apical membrane of enterocytes and hepatocytes. In enterocytes, this complex rejects plant sterols, whereas it promotes their excretion into the bile in the liver. The loss of function of the transporter ABCG5-G8 leads to a high concentration of plasma plant sterols and to its accumulation in tissues. We report here a new mutation of sitosterolemia in a 59-year-old woman with xanthelasma, precocious atherosclerosis, haemolytic anemia and macrothrombocytopenia. She was treated before the availability of Ezetimibe wich is now the gold standard treatment of this disease.