Diamond-Blackfan Anemia (DBA) is characterized by a defect of erythroid progenitors and, clinically, by anemia and malformations. DBA exhibits an autosomal dominant pattern of inheritance with incomplete penetrance. Currently nine genes, all encoding ribosomal proteins (RP), have been found mutated in approximately 50% of patients. Experimental evidence supports the hypothesis that DBA is primarily the result of defective ribosome synthesis. By means of a large collaboration among six centers, we report here a mutation update that includes nine genes and 220 distinct mutations, 56 of which are new. The DBA Mutation Database now includes data from 355 patients. Of those where inheritance has been examined, 125 patients carry a de novo mutation and 72 an inherited mutation. Mutagenesis may be ascribed to slippage in 65.5% of indels, whereas CpG dinucleotides are involved in 23% of transitions. Using bioinformatic tools we show that gene conversion mechanism is not common in RP genes mutagenesis, notwithstanding the abundance of RP pseudogenes. Genotype–phenotype analysis reveals that malformations are more frequently associated with mutations in RPL5 and RPL11 than in the other genes. All currently reported DBA mutations together with their functional and clinical data are included in the DBA Mutation Database.

Communicated by Maria Rita Passos-BuenoDiamond-Blackfan anemia (DBA) is an inherited disease characterized by pure erythroid aplasia. Thirty percent (30%) of patients display malformations, especially of the hands, face, heart, and urogenital tract. DBA has an autosomal dominant pattern of inheritance. De novo mutations are common and familial cases display wide clinical heterogeneity. Twenty-five percent (25%) of patients carry a mutation in the ribosomal protein (RP) S19 gene, whereas mutations in RPS24, RPS17, RPL35A, RPL11, and RPL5 are rare. These genes encode for structural proteins of the ribosome. A link between ribosomal functions and erythroid aplasia is apparent in DBA, but its etiology is not clear. Most authors agree that a defect in protein synthesis in a rapidly proliferating tissue, such as the erythroid bone marrow, may explain the defective erythropoiesis. A total of 77 RPS19 mutations have been described. Most are whole gene deletions, translocations, or truncating mutations (nonsense or frameshift), suggesting that haploinsufficiency is the basis of DBA pathology. A total of 22 missense mutations have also been described and several works have provided in vitro functional data for the mutant proteins. This review looks at the data on all these mutations, proposes a functional classification, and describes six new mutations. It is shown that patients with RPS19 mutations display a poorer response to steroids and a worse long-term prognosis compared to other DBA patients. Hum Mutat 29(7), [911][912][913][914][915][916][917][918][919][920] 2008.

discontinuation: 60% compared to 7AE6% in the slow tapering group (P = 0AE001). Cumulative incidence of MDS/AML was 8% at 10 years, with a significant correlation with both G-CSF cumulative dose and second IST. This long-term follow-up of children with AAA shows that IST with a slow CyA tapering course is an effective treatment with a low-relapse rate in these cases.

BackgroundDiamond-Blackfan anemia is a rare, pure red blood cell aplasia of childhood due to an intrinsic defect in erythropoietic progenitors. About 40% of patients display various malformations. Anemia is corrected by steroid treatment in more than 50% of cases; nonresponders need chronic transfusions or stem cell transplantation. Defects in the RPS19 gene, encoding the ribosomal protein S19, are the main known cause of DiamondBlackfan anemia and account for more than 25% of cases. Mutations in RPS24, RPS17, and RPL35A described in a minority of patients show that Diamond-Blackfan anemia is a disorder of ribosome biogenesis. Two new genes (RPL5, RPL11), encoding for ribosomal proteins of the large subunit, have been reported to be involved in a considerable percentage of patients. Design and MethodsIn this genotype-phenotype analysis we screened the coding sequence and intron-exon boundaries of RPS14, RPS16, RPS24, RPL5, RPL11, and RPL35A in 92 Italian patients with Diamond-Blackfan anemia who were negative for RPS19 mutations. ResultsAbout 20% of the patients screened had mutations in RPL5 or RPL11, and only 1.6% in RPS24. All but three mutations that we report here are new mutations. No mutations were found in RPS14, RPS16, or RPL35A. Remarkably, we observed a higher percentage of somatic malformations in patients with RPL5 and RPL11 mutations. A close association was evident between RPL5 mutations and craniofacial malformations, and between hand malformations and RPL11 mutations. ConclusionsMutations in four ribosomal proteins account for around 50% of all cases of DiamondBlackfan anemia in Italian patients. Genotype-phenotype data suggest that mutation screening should begin with RPL5 and RPL11 in patients with Diamond-Blackfan anemia with malformations.Key words: red cells, bone marrow failure, anemia, DBA, ribosomal proteins.Citation: Quarello P, Garelli E, Carando A, Brusco A, Calabrese R, Dufour C, Longoni D, Misuraca A, Vinti L, Aspesi A, Biondini L, Loreni F, Dianzani I, and Ramenghi U. Diamond-Blackfan anemia: genotype-phenotype correlations in Italian patients with RPL5 and RPL11 mutations Haematologica. 2010; 95:206-213. doi:10.3324/haematol.2009

SummaryAllogeneic haematopoietic stem cell transplantation (HSCT) is the only curative option for patients with Diamond Blackfan anaemia (DBA). We report the transplantation outcome of 30 Italian DBA patients referred to the Italian Association of Paediatric Haematology and Oncology Registry between 1990 and 2012. This is one of the largest national registry cohorts of transplanted DBA patients. Most patients (83%) were allografted after 2000. A matched sibling donor was employed in 16 patients (53%), the remaining 14 patients (47%) were transplanted from matched unrelated donors. Twenty-eight of the 30 patients engrafted. One patient died at day +6 due to veno-occlusive disease without achieving neutrophil recovery and another patient remained transfusion-dependent despite the presence of a full donor chimerism. The 5-year overall survival and transplantrelated mortality was 74Á4% and 25Á6%, respectively. Patients younger than 10 years as well as those transplanted after 2000 showed a significantly higher overall survival and a significantly lower risk of transplant-related mortality. No difference between donor type was observed. Our data suggest that allogeneic HSCT from a related or unrelated donor was a reasonable alternative to transfusion therapy in young and well chelated DBA patients.