NEET PG Medical – 2018 – Question – 35

Correct Answer – A
Answer: A. Paroxysmal nocturnal hemoglobinuria (PNH)
Paroxysmal nocturnal hemoglobinuria (PNH) is a disease, due to acquired mutations in “Phosphatidylinositol GlycanComplementation Group A” gene (PIGA)..
Associated with deficiency of glycosylphosphatidylinositol (GPI) anchor proteins along with absence of external surface
membrane proteins attaching to it.
CD55 (DAF) and CD59 (MIRL) are two such complement defence proteins
CD59 deficiency:
Common finding in RBCs & WBCs of patients with chronic hemolysis suffering from PNH
Diagnosis:
The definite diagnosis based on demonstration of a substantial proportion of patient’s RBC having increased susceptibility to complement (C), due to the deficiency on their surface of proteins (particularly CD59 & CD55).