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Paroxysmal nocturnal hemoglobinuria and complement-mediated erythrocyte damage
1University of Utah School of Medicine, Salt Lake City, USA.
Current Opinion in Hematology
|March 1, 1994
Summary
Paroxysmal nocturnal hemoglobinuria (PNH) involves red blood cells sensitive to complement lysis due to deficient regulatory proteins. A defective gene, PIG-A, causes abnormal glycosyl phosphatidylinositol anchor synthesis, explaining PNH molecularly.
Area of Science:
- Hematology
- Molecular Biology
- Genetics
Background:
- Paroxysmal nocturnal hemoglobinuria (PNH) erythrocytes exhibit complement-mediated lysis sensitivity.
- This sensitivity stems from deficient membrane proteins regulating complement activity.
- These deficient proteins are anchored to the cell surface via a glycosyl phosphatidylinositol (GPI) moiety.
Purpose of the Study:
- To identify the molecular basis of paroxysmal nocturnal hemoglobinuria (PNH).
- To investigate the abnormality in glycosyl phosphatidylinositol (GPI) anchor synthesis in PNH cells.
- To identify the gene responsible for correcting GPI anchor synthesis defects in PNH.
Main Methods:
- Expression cloning was utilized to identify the complementary DNA (cDNA).
- The identified cDNA was named phosphatidylinositol glycan class A (PIG-A).
- Gene localization studies determined the PIG-A gene's location on the X chromosome.
Main Results:
- PNH cells fail to form the first intermediate in glycosyl phosphatidylinositol (GPI) anchor biosynthesis.
- The identified phosphatidylinositol glycan class A (PIG-A) cDNA corrects GPI anchor synthesis abnormalities in PNH cells.
- The PIG-A gene was localized to the X chromosome.
Conclusions:
- The molecular basis of paroxysmal nocturnal hemoglobinuria (PNH) is an abnormality in a gene essential for GPI anchor biosynthesis.
- The PIG-A gene is identified as the gene responsible for this defect.
- These findings provide a comprehensive molecular explanation for PNH pathogenesis.