Array Comparative Genomic Hybridization of Ribosomal Protein Genes In Diamond-Blackfan Anemia Patients; Evidence for Three New DBA Genes, RPS8, RPS14 and RPL15, with Large Deletion or Duplication

Abstract 1007

Diamond-Blackfan anemia (DBA) is an inherited bone marrow failure syndrome characterized by anemia, usually presenting during infancy or in early childhood. Although anemia is the most prominent feature of DBA, the disease is also characterized by cancer predisposition, growth retardation and congenital malformations, in particular craniofacial, upper limb, heart and urinary system defects, which are present in ∼30-50% of patients. We completed our large scale sequencing of 80 ribosomal protein (RP) genes and found eight of them mutated in DBA. In total, together with three RP genes identified by others, there are 11 genes mutated in ∼54% of DBA patients; RPS19, RPS24, RPS17, RPL35A, RPL5, RPL11, RPS7, RPS10, RPS26, RPL19 and RPL26. To search for moderate and large RP gene deletions and duplications we performed high resolution array comparative genomic hybridization on 80 DNA samples from DBA patients who did not have mutations in the 11 known RP genes. We found a deletion of exon 2 and 3 (4800 bp), deletion of the coding region, and duplication of exons 2 and 3 (488 bp) in RPS19 gene in three probands; three deletions of exons 1, 2 and 3 in RPS17 in three probands (2920 bp, 2886 bp and 3018 bp); and deletion of exons 1, 2 and 3 of the RPS26 gene. We also identified two deletions and a duplication in three RP genes previously not found mutated in DBA; RPS8 duplication of exon 3 (764 bp), RPS14 deletion of exons 2, 3, 4 and 5 (2568 bp) and RPS15 deletion of exon 4 (1995 bp). The deletions and duplications are being confirmed by multiplex PCRs. Interestingly, RPS14 was previously identified as a 5q- syndrome gene demonstrating that abnormality of this protein can cause both DBA and 5q- syndrome. These data bring to 14 the total number of RP genes mutated in DBA.