Sitosterolemia: Unveiling an Underdiagnosed Case Series of Haemolytic Anaemia

Sitosterolemia is a rare autosomal recessive lipid metabolic condition characterized by excessive absorption of plant sterols through the intestinal mucosa, resulting in excessive sterols in the blood. Four patients of age ranging from 10 to 29 years presented to the outpatient department with clinical features of hemolytic anemia without any features of hypercholesterolemia. Peripheral smear examination of all patients showed stomatocytes and macro-thrombocytopenia. Next-generation sequencing revealed mutations in the ABCG5 gene: a homozygous c.727 C > T mutation, compound heterozygous c.1336 C > T and c.1292 C > G mutations in two cases, and homozygous mutation and deletion in the ABCG8 c.1720 G > A and c.408 del in two cases, respectively. Three of them were put on ezetimibe along with a low plant sterol diet and have shown significant hemoglobin improvement; the fourth patient has just started on the same. Our case series highlights a rare but manageable cause of hemolytic anemia suspected from peripheral blood examination, needing molecular genetic diagnosis with good results on proper management.