Diamond-Blackfan anemia (DBA) is a rare congenital erythroid hypoplastic anemia that usually presents early in infancy and is inherited in up to 45% of cases. It is characterized by red cell aplasia, congenital anomalies, and a predisposition to cancer. Corticosteroids and red blood cell transfusions are the mainstays of therapy. We describe a case of 3-month-old infant who presented with severe anemia, elevated levels of HbF and adenosine deaminase and bilateral hydronephrosis, who was later confirmed as DBA by mutation analysis using the direct sequencing method. Direct sequencing analysis of RPS19 gene was performed with both cDNA and genomic DNA extracted from peripheral blood and a c.3G>A point mutation of exon 2 resulting in p.Met1Ile was identified in this patient. The patient showed an inadequate response to steroid therapy and a partial response to RBC transfusion with a follow-up Hb level of 8.3 g/dL on her last visit to the outpatient clinic. DBA is a genetically and phenotypically heterogeneous disease, and we have reviewed the clinical characteristics of 25 Korean patients thus far reported in the literature. To our knowledge, this is the first case of DBA confirmed by mutation analysis in Korea, and mutation identification using molecular method is recommended for confirmation of this genetically and phenotypically heterogeneous disease.
Anemia, Diamond-Blackfan/*diagnosis/genetics/therapy ; Asian Continental Ancestry Group/*genetics ; Bone Marrow/pathology ; Erythrocyte Transfusion ; Exons ; Humans ; Infant ; Point Mutation ; Republic of Korea ; Ribosomal Proteins/*genetics ; Sequence Analysis, DNA

OBJECTIVETo enrich our national database with data of rare diseases by analyzing molecular diagnosis and hematopoietic stem cell transplantation (HSCT) in children with inherited bone marrow failure syndromes (IBMFS).

METHODNext-generation sequencing (NGS)-based genetic diagnosis panel was applied for the clinical diagnosis and management of IBMFS. Retrospective analysis was performed on clinical and genetic data of 17 consecutive children who received HSCT over a long time interval (November. 2005-June 2015).

RESULTThree patients were diagnosed only by clinical manifestation before 2012. After that NGS-based genetic diagnosis panel was used to identify IBMFS-related genes in 12/14.IBMFS patients (except two Diamond-Blackfan anemia (DBA) patients). Two Fanconi anemia (FA) patients were confirmed to be new variations through family-genotype-analysis and 3 families accepted prenatal diagnosis to avoid birth of affected fetuses. Seventeen IBMFS patients (10 FA,5 DBA and 2 dyskeratosis congenital (DKC)) were treated with HSCT from matched sibling donors (n=2), matched unrelated donors (n=8) or mismatched unrelated donors (n=7). The source of stem cells for transplantation included peripheral blood (n=12) and cord blood (n=5). With regard to the conditioning regimens, FA and DKC patients received fludarabine-based reduced intensity conditioning, while DBA patients received classical busulfan-based myeloablative conditioning. Median age at the time of HSCT was 36 months (7-156 months). The number of infused mononuclear cells and CD34⁺ cells was (10.6 ± 6.7) × 10⁸ and (5.9 ± 7.0) × 10⁶ per kilogram of recipient body weight, respectively. The median number of days to neutrophil recovery was 13 days after HSCT (range: 10-19 days). Platelet recovery was faster in the PBSCT group than in the CBT group ((16.3 ± 6.0) days vs. (30.0 ± 17.1) days,t=-2.487,P=0.026). During a median follow-up of 17 months (range: 2-114 months), except one FA patient who was transplanted with HLA-matched unrelated cord blood (CB) died from pneumonia and heart failure because of engraftment failure, other 16 children are alive after the successful HSCT. The failure-free survival rate of the patients three years after HSCT was 94%.

CONCLUSIONNGS-based molecular diagnosis technology and effective HSCT have significantly facilitated the treatment of children with IBMFS in our country, and our national database about this rare disease is to be further exploited.

Anemia, Aplastic ; Anemia, Diamond-Blackfan ; therapy ; Bone Marrow Diseases ; Child ; Dyskeratosis Congenita ; therapy ; Fanconi Anemia ; therapy ; Fetal Blood ; Hematopoietic Stem Cell Transplantation ; Hemoglobinuria, Paroxysmal ; diagnosis ; genetics ; therapy ; Humans ; Retrospective Studies ; Siblings ; Survival Rate ; Transplantation Conditioning ; Unrelated Donors ; Vidarabine ; analogs & derivatives ; therapeutic use