Hereditary spherocytosis associated with a deletion of human erythrocyte ankyrin gene on chromosome 8

Hereditary spherocytosis (HS) is characterized by the appearance of red blood cells which are globular, rather than with the normal indentation which is seen as a pale center under the microscope. This condition is the most common form of hereditary hemolytic anemia. Some patients have a mutation in the protein spectrin, which is found in large quantities just inside the membrane of red blood cells. However, the majority of patients with hereditary spherocytosis have no such mutation. Furthermore, the alpha and beta chains of spectrin have their genes on chromosomes 1 and 14, respectively, while the gene for HS seems to map to chromosome 8. Researchers have now cloned the gene for ankyrin, another important red cell protein, and found it to be located on chromosome 8, precisely at 8p11.2. Additionally, in two unrelated patients with HS, a deletion has been identified in this chromosomal region. Affected red cells were demonstrated to be ankyrin-deficient. While the location of the HS gene is not mapped with sufficient precision to say that it is indeed the anykrin gene, the results suggest that a defect or deficiency in ankyrin may be responsible for hereditary spherocytosis. (Consumer Summary produced by Reliance Medical Information, Inc.)