Seventeen years of misdiagnosis in rare dyslipidaemia: a case report of sitosterolaemia in a young female

BACKGROUND : Sitosterolaemia is a rare, autosomal recessive dyslipidaemia with increased absorption of dietary plant sterol and often presents with hypercholesterolaemia, xanthomas, and haematologic manifestations. If left untreated, sitosterolaemia can lead to high symptomatic burden and coronary artery disease (CAD). CASE SUMMARY : We describe a case of a young female who initially presented at 4 years of age with classic manifestations of sitosterolaemia. She was misdiagnosed and treated for both juvenile arthritis and later familial hypercholesterolaemia until adulthood, when venous blood samples showed significantly elevated concentrations of plant sterols. DNA analyses showed that the patient was homozygous for a mutation in the ABCG5 gene, [c.1336C>T, p.(Arg446*)], which is known to be associated with sitosterolaemia. DISCUSSION : Sitosterolaemia presents with multiple manifestations, which can initially be misinterpreted leading to prolonged misdiagnosis. Early diagnosis is key in order to relieve symptoms and prevent CAD.