Background: Phytosterolemia is a rare autosomal recessive lipid storage disease. It is caused by mutations of ABCG5 and ABCG8 genes and characterized by the increased plasma levels of plant sterols. The common clinical manifestations include tendon and tuberous xanthomas and premature coronary heart disease; it has occasionally been associated with hematologic abnormalities. Aims: We report a phytosterolemia patient presenting exclusively with macrothrombocytopenia and stomatocytic hemolysis and discuss its clinical significance. Case Report: The patient, aged 31 years, was born of a consanguineous marriage. He had epistaxis from childhood and underwent splenectomy because of thrombocytopenia, anemia and splenomegaly at the age of 9 years. His blood film showed prominent stomatocytes and macroplatelets. High performance liquid chromatography showed a grossly elevated level of phytosterols in the blood. The patient was confirmed to be a homozygote of missense mutation R419H in ABCG5. Conclusion: We describe a phytosterolemia patient whose clinical manifestations were macrothrombocytopenia, stomatocytic hemolysis and splenomegaly, without the common features of this disorder. Our results suggest that blood cells could be a target for the toxic effect of plasma plant sterols, which should be measured in patients with unexplained stomatocytosis and/or macrothrombocytopenia in order to determine if they have phytosterolemia.

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