Sickle cell disease true is -a) Mutation in α chainb) Symptoms ameliorated by HbFc) Venoocclusive crises is cause of morbidityd) Bone pain is presenting feature
**Core Concept**
Sickle cell disease is a genetic disorder caused by a mutation in the beta-globin chain of hemoglobin, leading to abnormal hemoglobin polymerization and red blood cell sickling. This results in various clinical manifestations, including vaso-occlusive crises, hemolytic anemia, and other complications.
**Why the Correct Answer is Right**
The correct answer is **C. Venoocclusive crises is cause of morbidity**. Venoocclusive crises occur due to the sickling of red blood cells in small blood vessels, leading to vascular obstruction, tissue ischemia, and severe pain. This is a major cause of morbidity in sickle cell disease. The sickling of red blood cells is triggered by factors such as hypoxia, acidosis, and dehydration, which can lead to the activation of the polymerization of abnormal hemoglobin, resulting in vaso-occlusive crises.
**Why Each Wrong Option is Incorrect**
**Option A:** The mutation in sickle cell disease is in the beta-globin chain, not the alpha chain. Alpha-thalassemia is a different genetic disorder affecting the alpha-globin chain.
**Option B:** Symptoms of sickle cell disease are not ameliorated by HbF (fetal hemoglobin). In fact, HbF is often elevated in sickle cell disease, and it can provide some protection against vaso-occlusive crises.
**Option D:** Bone pain is a common symptom of sickle cell disease, but it is not the presenting feature. The presenting features of sickle cell disease can vary, but they often include symptoms such as anemia, jaundice, and episodes of pain.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that sickle cell disease is a multisystem disorder that can affect various organs, including the spleen, kidneys, and brain. Early diagnosis and management are crucial to prevent complications and improve the quality of life for patients with sickle cell disease.
**Correct Answer:** C. Venoocclusive crises is cause of morbidity