Question

In which of the following condition altered redox state of haemoglobin is seen?

• A. \( \text{Aplastic anaemia} \)
• B. \( \text{Methemoglobinemia} \)
• C. \( \text{Sideroblastic anaemia} \)
• D. \( \text{Megaloblastic anaemia} \)

Hint:

Remember "meth" in methemoglobinemia refers to the altered iron state (Fe$^{3+}$) in hemoglobin, which can't carry oxygen properly.

Answer 1

The Correct Option is B

Methemoglobinemia is a condition characterized by the presence of a higher-than-normal level of methemoglobin in the blood. Methemoglobin is a form of hemoglobin where the iron in the heme group is in the ferric (Fe$^{3+}$) state, rather than the ferrous (Fe$^{2+}$) state of normal hemoglobin. This ferric form cannot bind oxygen effectively, leading to reduced oxygen delivery to tissues. Thus, methemoglobinemia directly involves an altered redox state of hemoglobin. Aplastic anemia is characterized by bone marrow failure leading to a deficiency of all blood cell types. Sideroblastic anemia involves the bone marrow producing ringed sideroblasts (erythroblasts with iron-laden mitochondria). Megaloblastic anemia is characterized by the presence of large, abnormal red blood cell precursors in the bone marrow, often due to vitamin B12 or folate deficiency. While these conditions affect hemoglobin levels or red blood cell production, they do not primarily involve an altered redox state of the iron in hemoglobin itself, as seen in methemoglobinemia.