A nine month old boy parents presented to you with complaints of progressive lethargy, irritability & pallor since 6 months of age. Examination revealed severe pallor. Investigation showed Hb-3.8 mg%; MCV-58 fl; MCH-19.4 pg/cell. Blood film shows osmotic fragility is normal (target cells and normoblasts). X-ray skull shows expansion of erythroid marrow. Which of the following is the most likely diagnosis?

This child is having microcytic (MCV-58Fl), hypochromic(MCHC-19.4pg/cell) anemia with normal osmotic fragility. This is suggestive of iron deficiency anemia (Normal Hb at this age is 12g/dL, MCV is 78 fL). Severe iron deficiency will produce bizzare peripheral blood smear with severely hypochromic cells, target cells, hypochromic pencil shaped cells and occasionally small number of nucleated red blood cells. Ref: O P Ghai Essential Pediatrics, 6th Edition, Pages 300-302