A complete blood count on a 12-month-old infant reveals microcytic, hypochromic anemia with a hemoglobin level of 9.5 g/dL. The infant presents with mild pallor and no hepatosplenomegaly. What is the most likely diagnosis?

Choice A reason: Sickle-cell anemia typically presents with normocytic anemia and may include signs such as dactylitis, splenomegaly, or pain crises. It is not characteristically microcytic or hypochromic, and the absence of hepatosplenomegaly makes this diagnosis less likely in a 12-month-old. Choice B reason: Hereditary spherocytosis is associated with normocytic anemia and spherocytes on peripheral smear. It often presents with splenomegaly and jaundice, which are absent in this case. Additionally, the anemia described is microcytic and hypochromic, which is not typical of hereditary spherocytosis. Choice C reason: Iron-deficiency anemia is the most common cause of microcytic, hypochromic anemia in infants. A hemoglobin level of 9.5 g/dL with pallor and no hepatosplenomegaly strongly supports this diagnosis. Iron deficiency is often due to dietary insufficiency or prolonged exclusive breastfeeding without iron supplementation. Choice D reason: Lead intoxication can cause microcytic anemia, but it is usually associated with other signs such as developmental delay, irritability, or basophilic stippling on smear. The absence of environmental exposure history and the clinical presentation make this less likely than iron deficiency.