Hereditary nonspherocytic hemolytic anemia is a term used to describe a group of rare, genetically transmitted blood disorders characterized by the premature destruction of red blood cells (erythrocytes or RBCs). If the red blood cells cannot be replaced faster than they destroy themselves, anemia is the result.
In these disorders, the outside membrane of the cell is weakened, causing it to have an irregular, non-spherical shape and to burst (hemolyze) easily. These disorders are caused by, among other things, defects in the chemical processes involved in the breakdown of sugar molecules (glycolysis). Red blood cells depend on this process for energy and if an enzyme is defective in any one of the stages, the red blood cell cannot function properly and hemolysis, or the breakdown of the membrane that holds the cell together, takes place. The more common of the enzyme deficiencies that lead to HNSHA involve glucose-6-phosphate dehydrogenase (G6PD) deficiency, pyruvate kinase deficiency and hexokinase deficiency. There may be as many as 16 red blood cell enzyme abnormalities that may cause hereditary nonspherocytic hemolytic anemia. In addition, HNSHA may arise as the result of immune disorders, toxic chemicals and drugs, antiviral agents (eg, ribavirin), physical damage, and infections.
