Increased fetal hemoglobin is seen in –
**Core Concept**
Increased fetal hemoglobin (HbF) is a condition where there is an elevated level of the embryonic hemoglobin, HbF, in adult red blood cells. This condition is often associated with a failure to switch from fetal to adult hemoglobin production, which normally occurs at birth.
**Why the Correct Answer is Right**
The correct answer is related to a condition where there is a persistence of fetal hemoglobin due to a mutation in the beta-globin gene cluster. Normally, the beta-globin gene is silenced after birth, and the gamma-globin gene is responsible for producing HbF. However, in individuals with beta-thalassemia major, the mutation in the beta-globin gene cluster leads to the production of HbF, which can range from 20-90% of the total hemoglobin. This is because the mutation disrupts the normal switch from gamma-globin to beta-globin production.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not related to the condition of increased fetal hemoglobin.
* **Option B:** This option is not a correct association with increased fetal hemoglobin.
* **Option C:** This option is not a correct association with increased fetal hemoglobin.
**Clinical Pearl / High-Yield Fact**
Beta-thalassemia major, also known as Cooley's anemia, is a severe form of thalassemia that requires regular blood transfusions to manage the condition. The increased production of HbF in beta-thalassemia major is a key diagnostic feature of the condition.
**Correct Answer:** D.