A 30-year-old Nigerian woman is found to have HbSC disease. Compared to homozygous HbSS sickle cell disease, HbSC disease typically shows:
- A Milder overall anemia but increased risk of proliferative retinopathy and avascular necrosis ✓
- B More severe vaso-occlusive crises and higher stroke risk
- C Identical clinical course with higher susceptibility to Streptococcal infections
- D Normal hemoglobin levels due to compensatory HbF production
Correct answer: A. Milder overall anemia but increased risk of proliferative retinopathy and avascular necrosis
Explanation
HbSC disease results from compound heterozygosity for HbS and HbC (glutamic acid→lysine substitution at codon 6 of beta-globin). Clinically, HbSC disease is milder than HbSS with less severe anemia and fewer acute pain crises, because HbC reduces mean corpuscular hemoglobin concentration less drastically. However, paradoxically, HbSC patients have a higher risk of proliferative sickle retinopathy and avascular necrosis of bone compared to HbSS.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.