Question

Larger and fragile RBCs with less haemoglobin are due to the deficiency of

• A. Castle's intrinsic factor.
• B. Factor III.
• C. Hageman factor.
• D. Cephalin.

Answer 1

The correct option is A Castle's intrinsic factor.

Castle's intrinsic factor is a glycoprotein that is secreted by the gastric mucous membrane (the parietal cells of the stomach) and is essential for the absorption of vitamin $B_{12}$ in the intestines. Vitamin $B_{12}$ cannot be produced by the human body and must be obtained from the diet. When foods containing vitamin $B_{12}$ are eaten, most of it is absorbed by the body in the small bowel (ileum) after binding to intrinsic factor. Pernicious anemia is developed due to the deficiency of vitamin $B_{12}$ caused by the absence of intrinsic factor. Pernicious anemia is characterized by large, fragile, immature erythrocytes, with less haemoglobin.Pernicious anemia can thus be diagnosed by conducting a 'full blood count' and 'blood smear' of the patient.