Sitosterolemia: Case Series of a Rare Genetic Disorder from India.

Sitosterolemia is a rare inherited autosomal recessive disorder characterized by the accumulation of plant sterols in the blood, due to mutations in the ABCG5 and/or ABCG8 genes, which encode the protein sterolin. This condition can potentially lead to premature cardiac death due to atherosclerosis. We report a series of four patients with sitosterolemia who presented to us with nonspecific symptoms. Most of them had received steroids arbitrarily at the previously visited clinics. All of them had stomatocytes and macrothrombocytes in peripheral blood smear examination. Next-generation sequencing (NGS) revealed ABCG5 gene mutation in two patients and ABCG8 gene mutation in the other two. None of them had xanthomas or liver disease. All of them responded to a low plant sterol diet and ezetimibe. To conclude, although rare, sitosterolemia should be considered in patients with thrombocytopenia and nonspecific symptoms once common etiologies are ruled out as this condition could cause premature cardiac death. Irrational steroid initiation without a diagnosis must be avoided. Basic peripheral blood smear examination which is also relatively inexpensive may provide immense amounts of information, as in our cases.