**Question:** An Afroamerican boy of 6 years of age presented with abdominal pain, chronic hemolysis and abnormal RBC shape on peripheral smear. Most likely disorder responsible for this condition is -

A. Sickle cell anemia
B. Diamond-Blackfan anemia
C. Thalassemia
D. Elliptocytosis

**Core Concept:**

The correct answer is based on the clinical presentation described: abdominal pain, chronic hemolysis, and abnormal red blood cell (RBC) shape on peripheral smear. We are considering the most common and relevant disorders involving RBC abnormalities and hemolysis in children. The main focus is on the diagnosis of the correct disorder among the given options.

**Why the Correct Answer is Right:**

Diamond-Blackfan anemia (DBA) is a rare genetic disorder of RBC production, which primarily affects infants and young children. It is characterized by aplastic anemia (decreased RBC production), macrocytosis (large RBCs), and a high red cell distribution width (RDW), indicating abnormal RBC shape. In this case, DBA is the most likely diagnosis due to the combination of abdominal pain, chronic hemolysis, and abnormal RBC shape.

**Why Each Wrong Option is Incorrect:**

1. Sickle cell anemia: This disorder is caused by a mutation in the HBB gene, leading to abnormal hemoglobin S. It results in sickle-shaped RBCs and typically presents in early infancy or childhood. The patient described has chronic hemolysis, but the abdominal pain is not the primary symptom in sickle cell anemia.

2. Thalassemia: This is a group of inherited blood disorders characterized by reduced or absent production of hemoglobin chains (alpha or beta). The main clinical features include microcytosis (small RBCs), hypochromia (reduced hemoglobin content), and polycythemia (increased red blood cell count). In this case, the abdominal pain is not the primary symptom, and the patient presents with chronic hemolysis and abnormal RBC shape.

3. Elliptocytosis: This condition is caused by a genetic defect in RBC membrane proteins, leading to elliptic or oval-shaped RBCs. The main features are microcytosis, polychromasia (increased number of immature RBCs), and poikilocytosis (varied RBC shapes). The abdominal pain is not the primary symptom, and the patient presents with chronic hemolysis and abnormal RBC shape.

4. Diamond-Blackfan anemia: As explained above, this is the correct answer.

**Clinical Pearls:**

1. The clinical presentation of DBA includes chronic hemolysis, macrocytosis (large RBCs), and increased reticulocytes (young RBCs). Abdominal pain is not the primary symptom in DBA.
2. Abdominal pain is more common in sickle cell disease, which is not the correct answer in this case.

3. Reticulocytopenia (low reticulocyte count) is not a feature of DBA, as it is present in neonatal anemia and thal