Question:
CD59 is a marker of which disease?
CD59 is a marker of which disease?
Show Hint
CD59 is a GPI-anchored complement regulator lost when the GPI anchor fails.
Updated On: Jun 24, 2026
- PNH
- PTEN
- BRR
- Cowden syndrome
Show Solution
Verified By Collegedunia
The Correct Option is A
Solution and Explanation
Step 1: Paroxysmal nocturnal haemoglobinuria (PNH) is caused by an acquired mutation in the PIGA gene, which is required to make the glycosylphosphatidylinositol (GPI) anchor.
Step 2: Without the GPI anchor, surface proteins that depend on it are lost. Two of these are the complement-regulatory proteins CD55 (DAF) and CD59 (MIRL).
Step 3: Loss of CD55 and CD59 leaves red cells unprotected against complement, causing complement-mediated intravascular haemolysis. Flow cytometry showing deficient CD59 and CD55 on blood cells is the definitive diagnostic test for PNH. Hence the answer is PNH.
Step 4: The distractors are unrelated: PTEN is a tumour-suppressor gene, and Cowden syndrome and BRR (Bannayan-Riley-Ruvalcaba) are PTEN-related hamartoma syndromes, not CD59-defined disorders.
Step 2: Without the GPI anchor, surface proteins that depend on it are lost. Two of these are the complement-regulatory proteins CD55 (DAF) and CD59 (MIRL).
Step 3: Loss of CD55 and CD59 leaves red cells unprotected against complement, causing complement-mediated intravascular haemolysis. Flow cytometry showing deficient CD59 and CD55 on blood cells is the definitive diagnostic test for PNH. Hence the answer is PNH.
Step 4: The distractors are unrelated: PTEN is a tumour-suppressor gene, and Cowden syndrome and BRR (Bannayan-Riley-Ruvalcaba) are PTEN-related hamartoma syndromes, not CD59-defined disorders.
Was this answer helpful?
0
0
Top NEET PG Pathology Questions
- Which of the following is true regarding the Mendelian mode of inheritance?
- A child presents with intermittent jaundice and splenomegaly. There is a history of similar complaints in the elder brother. Peripheral smear shows the following finding. How will you investigate this condition?
- An African child is found to have a mass in the jaw. A biopsy of the mass was done, and it appears as shown in the image below. The child also had a translocation of t(8;14). What is the probable diagnosis?
- A child presented to the hospital with cola-colored urine, hypertension, and puffiness of eyes. Laboratory investigations were done, and creatinine was 2.5 mg/dL. Treatment was started, and despite treatment, the patient did not improve for the next 3 weeks. The creatinine value increased to 4.5 mg/dL. Which among the following electron microscopic findings will be seen in this patient ?
- A patient was transfused 4 units of blood 2 hours ago, and now she complains of chest discomfort. X-ray shows bilateral fissural thickening. Which of the following is the most probable cause ?
View More Questions
Top NEET PG Hemolytic Anemia Questions
Top NEET PG Questions
- A patient hailing from Delhi presents with fever, arthralgia, and extensive petechial rash for 3 days. Lab investigations revealed a hemoglobin of 9 g/ dL, a white blood cell count of 9000 cells/mm3, a platelet count of 20000 cells/mm3, and a prolonged bleeding time. The clotting time was normal. What is the most likely diagnosis?
- Which of the following statements is true about Trichomonas vaginalis?
- A lady from West Rajasthan presented with an ulcer surrounded by erythema on the right leg. Microscopy of the biopsy from the edge of the ulcer showed organisms with dark staining nuclei and kinetoplast. What is the most likely causative agent?
- A child presents with a fever and a rash. Urine examination showed cells with owl's eye appearance. What is the most likely diagnosis?
- Infection with Clonorchis sinensis is associated with an increased risk of__?
View More Questions