Diamond-Blackfan Anaemia: an overview

A de novo 1.6Mb microdeletion at 19q13.2 in a boy with Diamond-Blackfan anemia, global developmental delay and multiple congenital anomalies

Backgroud

Microdeletions at 19q13.2 are very rare. Only two cases have been previously described. Here we report a 2-year-2-month old boy with Diamond-Blackfan anemia, global developmental delay, cognitive impairments, distinctive facial features, behavior problems, skeletal and genital dysplasia.

Case presentation

A de novo 1.6 Mb microdeletion at 19q13.2q13.31 was detected by chromosomal microarray analysis. Haploinsufficiency of the RPS19 gene is known to cause Diamond-Blackfan anemia, other features in this patient are likely due to the deletion of other candidate genes such as PAFAH1B3, ERF, LIPE and GSK3A.

Conclusion

The deletion detected in our patient overlapped and was significantly smaller than the ones previously reported, which offered the opportunity to further define the critical region for this proposed contiguous gene deletion syndrome.

Electronic supplementary material

The online version of this article (doi:10.1186/s13039-016-0268-2) contains supplementary material, which is available to authorized users.

Growth hormone improves short stature in children with Diamond-Blackfan anemia

BACKGROUND

Diamond-Blackfan anemia (DBA), an inherited marrow failure syndrome, has severe hypoplastic anemia in infancy and association with aplastic anemia, MDS/leukemia, and other malignancies. Short stature is present in most patients. Isolated cases have demonstrated improved growth on growth hormone (GH) therapy.

PROCEDURES

GH treatment data were obtained from 19 children with DBA (6 at our site and 13 from Genentech). Control data from 44 non-GH treated children were provided by Diamond Blackfan Anemia Registry. Annual growth velocity (GV) and height-for-age Z-scores (HAZ) were compared between groups and for up to 4y of GH treatment.

RESULTS

Constructed DBA-specific male and female height-for-age charts for non-GH treated patients revealed short stature compared to CDC norms. GH-treated patients had significantly lower HAZ prior to treatment initiation compared to non-GH-treated controls. Among GH-treated patients, GV significantly improved in the first two years relative to pre-treatment. HAZ significantly improved in each of 4y of GH therapy compared to baseline. After 2y of therapy, HAZ for GH-treated patients were not significantly different from controls, demonstrating successful catch-up growth.

CONCLUSIONS

GH treatment in children with DBA improves both GV and HAZ during treatment sustained for up to 4y. Very short children with DBA can be treated successfully with GH to restore stature to levels comparable to less affected patients. DBA height charts are useful tools for assessing age-specific growth in this typically short population. Careful consideration of individualized benefit of GH therapy versus risk is important in view of long-term underlying ∼5% malignancy risk in DBA.

Disorders of sex development and Diamond-Blackfan anemia: is there an association?

Diamond-Blackfan anemia (DBA) is a rare disorder characterized by congenital pure red cell aplasia. Mutations in ribosomal protein S19 (RPS19) have been identified in 25% of DBA patients. More recently, mutations in other ribosomal protein genes, namely RPS7, RPS15, RPS24, RPS17, RPS27A, RPL35a, RPL36, RPL11, and RPL5, have also been found in patients with DBA. Approximately 30-40% of affected patients have various associated physical anomalies, mostly craniofacial and at the extremities, but also cardiac or urogenital malformations. Anomalies of the urogenital tract in DBA patients comprise changes in the kidney (dysplasia, agenesis, duplication, horseshoe kidney) and genitalia (hypospadias). To date, disorders of sex development (DSD) have only been described once in association with DBA. We report here four DBA patients who exhibited DSD.

RPL41, a small ribosomal peptide deregulated in tumors, is essential for mitosis and centrosome integrity

Ribosomal large subunit protein RPL41 is a basic (positively charged) peptide consisting of only 25 amino acids. An antisense-based functional screening revealed that the down-regulation of RPL41 led to an anchorage-independent growth of NIH3T3 cells in soft agar plates. RPL41 depletion with gene-specific small interfering RNA also resulted in malignant transformation of NIH3T3 cells including increased tumor growth in mice. RPL41 deletion was detected in 59% of tumor cell lines by fluorescence in situ hybridization analyses and RPL41 down-regulation in 75% of primary breast cancers by real-time quantitative reverse transcription-polymerase chain reaction. These studies suggest a tumor suppression role for RPL41. By mass spectrometry, RPL41 was associated with several cytoskeleton components including tubulin beta, gamma, and myosin IIA, which was confirmed by Western blot analysis on both cellular lysis and individually in vitro-expressed proteins. RPL41 also bound directly to polymerized tubulins. Cells overexpressing a GFP-RPL41 were resistant to nocodazole-induced microtubule depolymerization. A synthetic RPL41 induced cellular alpha-tubulin acetylation and G(2)/M cell cycle arrest. These results indicate a stabilizing role of RPL41 on microtubule. Microtubule spindles are essential for chromosome segregation during mitosis. Cells with RPL41 knock-down showed abnormal spindles, frequent failure of cytokinesis, and formation of polynuclear cells. In interphase cells, RPL41-depleted cells had premature splitting of centrosome. Our results provide evidence that RPL41 is a microtubule-associated protein essential for functional spindles and for the integrity of centrosome and that the abnormal mitosis and disrupted centrosome associated with the RPL41 down-regulation may be related to malignant transformation.

Congenic mice confirm that collagen X is required for proper hematopoietic development

The link between endochondral skeletal development and hematopoiesis in the marrow was established in the collagen X transgenic (Tg) and null (KO) mice. Disrupted function of collagen X, a major hypertrophic cartilage matrix protein, resulted in skeletal and hematopoietic defects in endochondrally derived tissues. Manifestation of the disease phenotype was variable, ranging from perinatal lethality in a subset of mice, to altered lymphopoiesis and impaired immunity in the surviving mice. To exclude contribution of strain specific modifiers to this variable manifestation of the skeleto-hematopoietic phenotype, C57Bl/6 and DBA/2J collagen X congenic lines were established. Comparable disease manifestations confirmed that the skeleto-hematopoietic alterations are an inherent outcome of disrupted collagen X function. Further, colony forming cell assays, complete blood count analysis, serum antibody ELISA, and organ outgrowth studies established altered lymphopoiesis in all collagen X Tg and KO mice and implicated opportunistic infection as a contributor to the severe disease phenotype. These data support a model where endochondral ossification-specific collagen X contributes to the establishment of a hematopoietic niche at the chondro-osseous junction.

Successful allogeneic bone marrow transplantation for diamond-blackfan anemia complicated by severe cardiac dysfunction due to transfusion-induced hemochromatosis

A 21-year-old man who was diagnosed with Diamond-Blackfan anemia at 2 years of age came to our hospital with the hope of undergoing bone marrow transplantation (BMT). He had been red cell transfusion-dependent for about 8 years; at presentation he had transfusion-induced hemochromatosis, a subsequent low left ventricular ejection fraction (LVEF) of 43%, and diabetes mellitus requiring insulin therapy. He received unrelated BMT with reduced intensity conditioning and sufficient GVHD prophylaxis. Regardless of the cardiac dysfunction, he had an uneventful course during pre- and post-grafting periods, and is currently doing well with an improved LVEF (55%), although he is still insulin dependent.

Altered endochondral ossification in collagen X mouse models leads to impaired immune responses

Disruption of collagen X function in hypertrophic cartilage undergoing endochondral ossification was previously linked to altered hematopoiesis in collagen X transgenic (Tg) and null (KO) mice (Jacenko et al., [2002] Am J Pathol 160:2019-2034). Mice displayed altered growth plates, diminished trabecular bone, and marrow hypoplasia with an aberrant lymphocyte profile throughout life. This study identifies altered B220+, CD4+, and CD8+ lymphocyte numbers, as well as CD4+/fox3P+ T regulatory cells in the collagen X mice. Additionally, diminished in vitro splenocyte responses to mitogens and an inability of mice to survive a challenge with Toxoplasma gondii, confirm impaired immune responses. In concert, ELISA and protein arrays identify aberrant levels of inflammatory, chemo-attractant, and matrix binding cytokines in collagen X mouse sera. These data link the disruption of collagen X function in the chondro-osseous junction to an altered hematopoietic stem cell niche in the marrow, resulting in impaired immune function.

Development of cellular models for ribosomal protein S19 (RPS19)-deficient diamond–blackfan anemia using inducible expression of siRNA against RPS19

Diamond-Blackfan anemia (DBA) is a congenital red cell aplasia in which 25% of the patients have a mutation in the ribosomal protein S19 (RPS19) gene. No models exist for RPS19-deficient DBA and the molecular pathogenesis is unknown. To establish an in vitro inducible model for DBA, human erythroid leukemic cell lines, TF-1 and UT-7 cells, were cotransduced with a lentiviral vector expressing the green fluorescent protein (GFP) gene and small interfering RNA (siRNA) against RPS19 controlled by a tet operator regulatory element and another transactivator vector containing the red fluorescent protein (RFP) gene and the cDNA encoding a tetracycline-controllable transcriptional repressor. Following transduction, the RFP-positive and GFP-negative cell population was sorted by flow cytometry. Upon incubation with doxycycline (0.5 mug/ml), more than 98% of cells expressed GFP and the siRNA. Significant suppression of erythroid differentiation, cell growth, and colony formation was observed in cells treated with siRNA against RPS19 but not in cells treated with a control vector. These findings show that RPS19 plays an important role in the regulation of hematopoietic cell proliferation and erythroid differentiation. These novel cell lines represent models for RPS19-deficient DBA and can be used to identify the molecular mechanisms in RPS19-deficient DBA.

Successful treatment of Diamond-Blackfan anemia with metoclopramide

Diamond-Blackfan anemia (DBA) is a congenital anemia characterized by a low reticulocyte count, the absence or severe reduction of hemoglobin-containing cells in the bone marrow, and normal megakaryocytic and granulocytic differentiation. Although the anemia may initially respond to corticosteroid therapy, many patients require lifelong red blood cell (RBC) transfusion, leading to infectious complications and iron overload. Metoclopramide has recently been used to treat DBA. Treatment with metoclopramide induces the release of prolactin from the pituitary and stimulates erythropoiesis. For these reasons, we used metoclopramide to treat a 20-year-old man with DBA refractory to low and high doses of corticosteroids, cyclosporin A, and tacrolimus (FK506). The hemoglobin and hematocrit slowly increased, and he has remained asymptomatic and transfusion-independent for 8 months. Metoclopramide therapy should be considered in patients with refractory DBA before treatment-related complications develop.

Congenital aplastic anemia caused by mutations in the SBDS gene: a rare presentation of Shwachman-Diamond syndrome

CLINICAL FINDINGS

Aplastic anemia was diagnosed at birth for a first child from healthy nonconsanguineous parents. The girl had hypoglycemia, which normalized within 2 months. Cow milk allergy was suspected initially, because of skin lesions and diarrhea, followed by severe growth retardation. Clinical and radiologic symptoms gradually became typical for Shwachman-Diamond syndrome. Two common mutations in the SBDS gene (183-184TA-->CT [K62X] and IVS2(258)+2T--> C [C84fs]) were found.

RESULTS

Bone marrow transplantation from a matched unrelated donor was unsuccessful. The genetic information from the deceased patient enabled us to perform prenatal molecular studies during the subsequent pregnancy, successfully predicting a nonaffected child.

CONCLUSIONS

This report describes for the first time the hematologic abnormalities of congenital aplastic anemia and prolonged neonatal hypoglycemia as the presenting symptoms of Shwachman-Diamond syndrome. The finding of common mutations in the presence of these symptoms at birth suggests the lack of a clear phenotype-genotype relationship in this syndrome.

Diamond-Blackfan anemia in Japan: clinical outcomes of prednisolone therapy and hematopoietic stem cell transplantation

The epidemiology and treatment outcomes for Diamond-Blackfan anemia (DBA) were surveyed in a cohort of 54 children (M/F = 26:28) registered in Japan from 1988 to 1998. The annual incidence was 4.02 cases per million births, the median age at diagnosis was 60 days, and 59% of the cases presented by 3 months of age. Three patients had a familial occurrence. All patients received prednisolone (PSL), and cyclosporin A (CsA) was added to the therapy in 17 patients. Forty-seven patients received transfusions, and 13 underwent hematopoietic stem cell transplantation (HSCT). The cumulative probabilities of a medication-free or a transfusion-free state prior to HSCT were 36% and 69%, respectively, at more than 5 years after diagnosis. Thirteen patients were weaned from PSL therapy without HSCT, and CsA was not associated with weaning from therapy. Transfusion and medication were stopped at 249 days and 933 days after diagnosis in 34 and 13 patients, respectively, who achieved a state of independence. No initial findings predicted the treatment dependence. More than 20% of patients experienced sustained hemosiderosis and/or adverse effects of PSL. The ages and reticulocyte counts at diagnosis of the patients who underwent HSCT were lower than in the patients who did not. HSCT led to the highest success (85%) of all previous reports, even though 5 alternative donors were included in our study. Two cord blood transplants from unrelated donors failed. These findings suggest the need for developing an integral treatment strategy including selective HSCT for refractory DBA.

Living With Diamond Blackfan Anemia

As the world of medicine and nursing advance, children with once terminal childhood diseases are now surviving into young adulthood. Nurses must learn to care for pediatric patients who transition to adulthood. This article explores Diamond Blackfan Anemia, once considered a terminal childhood disease that can now be a disease of young adulthood.

Fanconi anaemia

Fanconi anaemia (FA) is an autosomal recessive disease characterised by congenital abnormalities, defective haemopoiesis, and a high risk of developing acute myeloid leukaemia and certain solid tumours. Chromosomal instability, especially on exposure to alkylating agents, may be shown in affected subjects and is the basis for a diagnostic test. FA can be caused by mutations in at least seven different genes. Interaction pathways have been established, both between the FA proteins and other proteins involved in DNA damage repair, such as ATM, BRCA1 and BRCA2, thereby providing a link with other disorders in which defective DNA damage repair is a feature. This review summarises the clinical features of FA and the natural history of the disease, discusses diagnosis and management, and puts the recent molecular advances into the context of the cellular and clinical FA phenotype.

A practical approach to the evaluation of the anemic child

Anemia is a sign of disease and not a final diagnosis. The clinician's goal is to define the underlying cause. The anemia may be due to decreased production or Increased destruction or loss of red blood cells. Integration of the results of the initial CBC. particularly the RBC indices, the peripheral blood smear, the history and the physical examination can help organize the focus of further evaluations and, ultimately, minimize the number of tests needed to make a firm diagnosis.

Study of 22 Egyptian patients with Diamond-Blackfan anemia, corticosteroids, and cyclosporin therapy results

OBJECTIVE

Diamond-Blackfan anemia is a rare congenital hypoproliferative anemia of infancy and early childhood. Treatment with corticosteroids is commonly used, but with limited success. Trials with cyclosporin-A (CSA) are not frequently reported. Therefore, in this study we analyzed our results in the management of this rare disease by different medical treatments.

DESIGN

The results of 22 patients diagnosed at our Hematology Center in the New Cairo University Children's Hospital during the period 1991-2001 were retrospectively analyzed. Our patients first received prednisolone (2 mg/kg/d) for different courses according to their response. Since the year 2000, the steroid nonresponders received CSA (3-12 mg/kg/d) for 6 months unless treatment complications developed.

RESULTS

The age at the onset of the disease ranged from 1 to 24 months (median: 2.5 months). The mean values of the hemoglobin, the reticulocyte count, and the myeloid/erythroid ratio at the onset of the disease were 4.75 +/- 1.79 g/dL, 0.14 +/- 0.16, and 39.4 +/- 27.08, respectively. Patients received prednisolone from 0.25 to 10 years (median: 2 years). Ten patients were nonresponders (45.5%), and 5 patients (22.7%) responded to corticosteroid therapy. Two of 5 responders are off treatment with a hemoglobin level of >9 g/dL, and 3 of 5 are currently corticosteroid-dependent. Of 10 patients not responding to steroids, 8 received CSA for 6 months. Four patients (50%) responded to CSA therapy. A significant positive association was found between CSA dose and response.

CONCLUSION

CSA therapy should be tried in steroid-resistant Diamond-Blackfan anemia patients before blood transfusion or corticosteroid therapy complications are instituted.