ABCG5 and familial hypercholesterolemia: <h4>Background</h4>Sitosterolemia is an autosomal recessive genetic disorder characterized by hypercholesterolemia and tendon/hip xanthomas, primarily caused by pathogenic mutations in the ABCG5 or ABCG8 gene.<h4>Case presentation</h4>We report the clinical features and therapeutic outcomes of a 29-year-old Chinese male patient diagnosed with sitosterolemia.