© 2022Background: Sitosterolemia, also known as phytosterolemia, results from increased intestinal absorption of plant sterols and decreased intestinal and biliary excretion of sterols, resulting in increased levels of plant sterols in the plasma. The most common symptoms include xanthomas, premature atherosclerosis, hemolytic anemia and macrothrombocytopenia, however delayed diagnosis or misdiagnosis also occur. Patient and methods: Clinical exome sequencing was performed on a 10-year-old boy whom we followed up with signs of pancytopenia accompanied by macrothrombocytopenia and stomatocytosis. In addition, the blood sterol levels of the patient and his family were studied. Results: A novel homozygous c.904 + 5G > C intronic variant was detected in ABCG5 gene in index case. The mother and father were identified as carriers. The blood plant sterol levels of the patient and his family were studied, and the levels in the patient confirmed Sitosterolemia. Sitosterol levels decreased dramatically with restricted diet and ezetimibe treatment. Conclusion: In children, signs of Sitosterolemia may be subtle and the only symptom may be hematological. Therefore, Sitosterolemia should be kept in mind in children with stomatocytosis and macrothrombocytopenia.