ESPE Abstracts

Sitosterolemia is an autosomal recessive disorder affecting lipid metabolism which is characterized by decreased biliary excretion and increased absorption of plant sterols and cholesterol, leading to significantlyelevated serum levels of plant sterols. Approximately 80 homozygous or compound heterozygous variants in adenosine triphosphate-binding cassette subfamily G genes (ABCG5/ABCG8) genes have been described in patients with genetically confirmed sitosterolemia. Clinically, sitosterolemia has been associated with xanthomas, premature atherosclerotic events, and hematologic manifestations. Phenotypic characteristics of sitosterolemia have been described properly in case series or local cohort observations, but identifying this disease in clinically suspected patients can be difficult. It is vital to be able to recognize index cases so that urgent diagnosis and effective management can be provided for family members who might also be affected. We are presenting a 12 year old boy, medically free, presented to the primary care Clinic with 2 months history of episodic mild chest pain, mainly after exertion, associated with shortness of breath. Investigations were done and he was found to have high serum concentrations of lipids (LDL 6.3, Total Cholesterol 8) and normal levels of triglycerides. On examination, the patient had bilateral single tendon xanthoma over the extensor surfaces of the elbows (Measuring 3x2.5x3 cm). Familial dyslipidemia was suspected, and genetic testing was sent, which came back positive for a homozygous pathogenic variant in the ABCG5 gene, which gives a diagnosis of autosomal recessive sitosterolemia type 2. Our study findings and clinical manifestations has been consistent with most cases in the literature. However, our case hasn’t shown any hematological features, including thrombocytopenia, anemia, or splenomegaly, which are one of the key differentiators between sitosterolemia from familial hypercholesterolemia.