This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hemoglobinopathies: Sickle cell anemia, Subject name: Pathology
Decreased osmotic fragility is not seen in which of the following conditions? 
Select and explain. 
A. Thalassemia, B. Hereditary spherocytosis, C. Sickle cell anemia, D. Iron deficiency
B: Hereditary spherocytosis
Answer: B: Hereditary spherocytosis 
Explanation: - Hereditary spherocytosis is associated with increased osmotic fragility because RBCs are spherical & unstable d/t defect in their cytoskeleton. Osmotic fragility curves of normal and hereditary spherocytosis red blood cells.