Diamond-Blackfan anemia : Mapping and identification of the disease gene

Abstract: This thesis presents the positional cloning of the gene behind Diamond-Blackfan anemia. Evidence for the involvement of ribosomal protein (RP) S19 gene mutations in Diamond-Blackfan anemia is given. This is the first example of a human disease that is directly related to a ribosomal protein.A chromosomal translocation in a girl with DBA was characterized, using fluorescent in situ hybridization (FISH) to metaphase chromosomes. These results suggested that the disease gene is located on chromosome 19q13. Analysis of familial cases with DBA showed significant linkage for the disease to the region defined by the translocation breakpoint. FISH analysis of metaphase chromosomes identified a cosmid spanning the translocation breakpoint. Sequence analysis of the cosmid revealed a gene encoding the ribosomal protein S19 (RPS19), which is disrupted by the translocation. Subsequent analysis of the RPS19 gene in independent DBA patients revealed mutations that segregate with the disease. Diamond-Blackfan anemia is a disease characterized by a congenital defect of erythropoiesis with an absence or a reduction of the erythroblasts present in bone marrow. This disorder may act as a model for our further understanding of the regulation of red blood cell production. Several different factors involved in the production of red blood cells (erythropoiesis) have been identified. However, much is yet unknown regarding the complex regulatory mechanisms of hematopoietic stem cells and the results presented in this study provide another link in the erythropoietic pathway.