Diamond-Blackfan anemia (DBA) is the first human disease known to be caused by mutations in ribosomal protein (RP) genes. It is characterized by anemia, physical anomalies, and increased risk of malignancy. To date mutations in nine RP genes, RPS19, RPS24, RPS17, RPL35A, RPL5, RPL11, RPS7, RPS10 and RPS26 have been reported in ~53% of DBA patients. Recently, we finished screening all 80 ribosomal protein genes and have obtained evidence for mutations in two additional RP genes, RPL19 and RPL26, in ~2% of DBA patients. Despite this significant progress in deciphering the genetic causes of DBA, diagnostics and genetic counseling for these patients are still severely hampered by the fact that roughly 50% of cases have mutations in genes yet to be identified. This lack of confirmed genetic etiology also makes it difficult to create suitable animal model for DBA and to perform further studies on the mechanisms of the disease. To address this issue, we are performing comparative genomic hybridization on 150 DNA samples from DBA probands without known mutations to search for deletions and duplications in the 80 RP genes we have already sequenced. We also propose to perform whole exome sequencing (""""""""next generation"""""""" sequencing) on 28 DNA samples from DBA probands who were screened for all 80 RP genes and are negative for mutations in these genes. Comparative genomic hybridization will allow us to identify microdeletions or duplications in RP and other candidate genes;the whole exome sequencing (sequencing of all exons and intron-exon boundaries) will allow us to identify the additional DBA genes, which we hypothesize will likely encode proteins involved in ribosomal biogenesis or function. To further test our hypothesis that abnormal ribosomal biogenesis underlies the mechanism of DBA in all patients, we will also perform pre-rRNA maturation assays on RNA samples from lymphoblastoid cell lines from patients with mutations in the newly discovered genes. Our hypothesis predicts that abnormal maturation of pre-rRNA will be a common feature in patients with newly discovered genes. We also hypothesize that profound clinical heterogeneity in DBA is a consequence of genetic variants that influence the presence of associated congenital birth defects or patients'response to steroid treatment. Investigating the influence of these variants would expand our understanding of the mechanism of DBA and potentially, especially for the association with response to steroids, could be a platform for the targeted therapies for DBA. The following three specific aims will allow us to find the genetic basis of DBA and the molecular mechanism of anemia in this disease.
Specific Aim 1. Identify the novel gene(s) causing DBA in about 50% of patients without known mutations.
Specific Aim 2. Determine the role of DBA genes in pre-RNA maturation.
Specific Aim 3. Identify modifier genes in DBA by performing a genome-wide association study.

Public Health Relevance

Diamond-Blackfan anemia is the first human disease known to be caused by mutations in ribosomal protein genes. It is characterized by anemia, physical anomalies, and increased risk of malignancy. The treatment of choice is a steroid therapy, but this has significant side effects. In order to find better treatments for these patients it is important to know the genetic basis and understand the mechanism of the disease. The goal of this project, is to identify genes in approximately 50% of patients without known mutations and to explore the role of ribosomal proteins in the pathogenesis of Diamond-Blackfan anemia, which will establish the basis for better treatment discovery.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL107558-02
Application #
8316126
Study Section
Molecular and Cellular Hematology (MCH)
Program Officer
Qasba, Pankaj
Project Start
2011-08-08
Project End
2015-06-30
Budget Start
2012-07-01
Budget End
2013-06-30
Support Year
2
Fiscal Year
2012
Total Cost
$418,500
Indirect Cost
$166,500
Name
Children's Hospital Boston
Department
Type
DUNS #
076593722
City
Boston
State
MA
Country
United States
Zip Code
02115
Doulatov, Sergei; Vo, Linda T; Macari, Elizabeth R et al. (2017) Drug discovery for Diamond-Blackfan anemia using reprogrammed hematopoietic progenitors. Sci Transl Med 9:
Kim, Ah Ram; Ulirsch, Jacob C; Wilmes, Stephan et al. (2017) Functional Selectivity in Cytokine Signaling Revealed Through a Pathogenic EPO Mutation. Cell 168:1053-1064.e15
Narla, Anupama; Yuan, Daniel; Kazerounian, Shideh et al. (2016) A novel pathogenic mutation in RPL11 identified in a patient diagnosed with diamond Blackfan anemia as a young adult. Blood Cells Mol Dis 61:46-7
Danilova, Nadia; Gazda, Hanna T (2015) Ribosomopathies: how a common root can cause a tree of pathologies. Dis Model Mech 8:1013-26
Ludwig, Leif S; Gazda, Hanna T; Eng, Jennifer C et al. (2014) Altered translation of GATA1 in Diamond-Blackfan anemia. Nat Med 20:748-53
Gagne, Katelyn E; Ghazvinian, Roxanne; Yuan, Daniel et al. (2014) Pearson marrow pancreas syndrome in patients suspected to have Diamond-Blackfan anemia. Blood 124:437-40
Heijnen, Harry F; van Wijk, Richard; Pereboom, Tamara C et al. (2014) Ribosomal protein mutations induce autophagy through S6 kinase inhibition of the insulin pathway. PLoS Genet 10:e1004371
Landowski, Michael; O'Donohue, Marie-Francoise; Buros, Christopher et al. (2013) Novel deletion of RPL15 identified by array-comparative genomic hybridization in Diamond-Blackfan anemia. Hum Genet 132:1265-74
Gazda, Hanna T; Preti, Milena; Sheen, Mee Rie et al. (2012) Frameshift mutation in p53 regulator RPL26 is associated with multiple physical abnormalities and a specific pre-ribosomal RNA processing defect in diamond-blackfan anemia. Hum Mutat 33:1037-44
Sankaran, Vijay G; Ghazvinian, Roxanne; Do, Ron et al. (2012) Exome sequencing identifies GATA1 mutations resulting in Diamond-Blackfan anemia. J Clin Invest 122:2439-43