The peripheral blood smear of an anemic 1-year-old child is shown in the illustration. The most likely diagnosis is
**Core Concept**
The peripheral blood smear in question likely shows characteristics of a specific type of anemia, which can be identified by examining the red blood cell morphology, size, and distribution. This condition is often associated with a genetic disorder affecting hemoglobin production.
**Why the Correct Answer is Right**
The peripheral blood smear in question is likely indicative of beta-thalassemia major, also known as Cooley's anemia. This condition is characterized by a significant reduction in the production of the beta-globin chains of hemoglobin, leading to severe anemia, marked by small, pale red blood cells (microcytic hypochromic anemia). The presence of target cells, which are a hallmark of beta-thalassemia major, is a key diagnostic feature. Target cells are formed when there is a mismatch between the alpha-globin and beta-globin chains, causing the red blood cell to assume a "bullseye" appearance.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not accurately describe the characteristic red blood cell morphology associated with beta-thalassemia major.
* **Option B:** This option is incorrect because it suggests a different type of anemia, such as iron deficiency anemia, which typically presents with microcytic hypochromic red blood cells but lacks the characteristic target cells seen in beta-thalassemia major.
* **Option C:** This option is incorrect because it implies a different genetic disorder affecting hemoglobin production, such as alpha-thalassemia major. While alpha-thalassemia major can also present with microcytic hypochromic anemia, it typically lacks the target cells seen in beta-thalassemia major.
**Clinical Pearl / High-Yield Fact**
Beta-thalassemia major is a severe form of anemia that requires regular blood transfusions to maintain adequate hemoglobin levels. It is essential to diagnose this condition early to prevent complications such as growth retardation, delayed puberty, and increased risk of infections.
**Correct Answer:** C.