Sitosterolemia caused by mutations in the ABCG8 gene. First case report in Colombia

Abstract

Introduction: Sitosterolemia is an autosomal recessive disease caused by mutations in the ABCG5 or ABCG8 genes. It is characterized by reduced excretion of plant sterols and cholesterol, leading to the development of hypercholesterolemia, xanthomas, and premature atherosclerosis. The present article reports the first case of this disease in Colombia. Case presentation: A 5-year-old child, son of non-consanguineous parents, who was under active treatment with ezetimibe and cholestyramine was taken (April 2021) to the human genetics service of a healthcare institution in Bogotá, Colombia, for assessment due to multiple xanthomas and elevated LDL cholesterol levels. Familial hypercholesterolemia had been ruled out. A next-generation gene sequencing (NGS) analysis detected a mutation in the ABCG8 gene, so he was diagnosed with sitosterolemia. Pharmacological treatment (ezetimibe and cholestyramine) was continued and dietary modifications were started. In the last follow-up visit of the patient to the human genetics service (March 2022), an improvement in the lipid profile was observed. In addition, 9 months later (December 2022), a decrease in the size of the xanthomas was reported in an evaluation by the pediatric endocrinology service. Conclusion: Sitosterolemia is a rare disease that should be considered in pediatric patients with multiple xanthomas and in whom familial hypercholesterolemia has been ruled out. Performing NGS of the genes involved is important to make a timely diagnosis and initiate appropriate treatment, which will improve the prognosis and quality of life of these patients.