GATA-1 Defects in Diamond-Blackfan Anemia: Phenotypic Characterization Points to a Specific Subset of Disease

Diagnosis, treatment, and surveillance of Diamond-Blackfan anaemia syndrome: international consensus statement

Diamond-Blackfan anaemia (DBA), first described over 80 years ago, is a congenital disorder of erythropoiesis with a predilection for birth defects and cancer. Despite scientific advances, this chronic, debilitating, and life-limiting disorder continues to cause a substantial physical, psychological, and financial toll on patients and their families. The highly complex medical needs of affected patients require specialised expertise and multidisciplinary care. However, gaps remain in effectively bridging scientific discoveries to clinical practice and disseminating the latest knowledge and best practices to providers. Following the publication of the first international consensus in 2008, advances in our understanding of the genetics, natural history, and clinical management of DBA have strongly supported the need for new consensus recommendations. In 2014 in Freiburg, Germany, a panel of 53 experts including clinicians, diagnosticians, and researchers from 27 countries convened. With support from patient advocates, the panel met repeatedly over subsequent years, engaging in ongoing discussions. These meetings led to the development of new consensus recommendations in 2024, replacing the previous guidelines. To account for the diverse phenotypes including presentation without anaemia, the panel agreed to adopt the term DBA syndrome. We propose new simplified diagnostic criteria, describe the genetics of DBA syndrome and its phenocopies, and introduce major changes in therapeutic standards. These changes include lowering the prednisone maintenance dose to maximum 0·3 mg/kg per day, raising the pre-transfusion haemoglobin to 9-10 g/dL independent of age, recommending early aggressive chelation, broadening indications for haematopoietic stem-cell transplantation, and recommending systematic clinical surveillance including early colorectal cancer screening. In summary, the current practice guidelines standardise the diagnostics, treatment, and long-term surveillance of patients with DBA syndrome of all ages worldwide.

Diamond-Blackfan anemia, the archetype of ribosomopathy: How distinct is it from the other constitutional ribosomopathies?

Diamond-Blackfan anemia (DBA) was the first ribosomopathy described in humans. DBA is a congenital hypoplastic anemia, characterized by macrocytic aregenerative anemia, manifesting by differentiation blockage between the BFU-e/CFU-e developmental erythroid progenitor stages. In 50 % of the DBA cases, various malformations are noted. Strikingly, for a hematological disease with a relative erythroid tropism, DBA is due to ribosomal haploinsufficiency in 24 different ribosomal protein (RP) genes. A few other genes have been described in DBA-like disorders, but they do not fit into the classical DBA phenotype (Sankaran et al., 2012; van Dooijeweert et al., 2022; Toki et al., 2018; Kim et al., 2017 [1-4]). Haploinsufficiency in a RP gene leads to defective ribosomal RNA (rRNA) maturation, which is a hallmark of DBA. However, the mechanistic understandings of the erythroid tropism defect in DBA are still to be fully defined. Erythroid defect in DBA has been recently been linked in a non-exclusive manner to a number of mechanisms that include: 1) a defect in translation, in particular for the GATA1 erythroid gene; 2) a deficit of HSP70, the GATA1 chaperone, and 3) free heme toxicity. In addition, p53 activation in response to ribosomal stress is involved in DBA pathophysiology. The DBA phenotype may thus result from the combined contributions of various actors, which may explain the heterogenous phenotypes observed in DBA patients, even within the same family.

Germline Variants and Characteristic Features of Hereditary Hematological Malignancy Syndrome

Due to the proliferation of genetic testing, pathogenic germline variants predisposing to hereditary hematological malignancy syndrome (HHMS) have been identified in an increasing number of genes. Consequently, the field of HHMS is gaining recognition among clinicians and scientists worldwide. Patients with germline genetic abnormalities often have poor outcomes and are candidates for allogeneic hematopoietic stem cell transplantation (HSCT). However, HSCT using blood from a related donor should be carefully considered because of the risk that the patient may inherit a pathogenic variant. At present, we now face the challenge of incorporating these advances into clinical practice for patients with myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) and optimizing the management and surveillance of patients and asymptomatic carriers, with the limitation that evidence-based guidelines are often inadequate. The 2016 revision of the WHO classification added a new section on myeloid malignant neoplasms, including MDS and AML with germline predisposition. The main syndromes can be classified into three groups. Those without pre-existing disease or organ dysfunction; DDX41, TP53, CEBPA, those with pre-existing platelet disorders; ANKRD26, ETV6, RUNX1, and those with other organ dysfunctions; SAMD9/SAMD9L, GATA2, and inherited bone marrow failure syndromes. In this review, we will outline the role of the genes involved in HHMS in order to clarify our understanding of HHMS.

Down syndrome and leukemia: from basic mechanisms to clinical advances

Children with Down syndrome (DS, trisomy 21) are at a significantly higher risk of developing acute leukemia compared to the overall population. Many studies investigating the link between trisomy 21 and leukemia initiation and progression have been conducted over the last two decades. Despite improved treatment regimens and significant progress in iden - tifying genes on chromosome 21 and the mechanisms by which they drive leukemogenesis, there is still much that is unknown. A focused group of scientists and clinicians with expertise in leukemia and DS met in October 2022 at the Jérôme Lejeune Foundation in Paris, France for the 1st International Symposium on Down Syndrome and Leukemia. This meeting was held to discuss the most recent advances in treatment regimens and the biology underlying the initiation, progression, and relapse of acute lymphoblastic leukemia and acute myeloid leukemia in children with DS. This review provides a summary of what is known in the field, challenges in the management of DS patients with leukemia, and key questions in the field.

Diamond-Blackfan anemia in adults: In pursuit of a common approach for a rare disease

Diamond-Blackfan anemia (DBA) is a rare bone marrow failure syndrome, usually caused by loss-of function variants in genes encoding ribosomal proteins. The hallmarks of DBA are anemia, congenital anomalies and cancer predisposition. Although DBA usually presents in childhood, the prevalence in later life is increasing due to an expanding repertoire of implicated genes, improvements in genetic diagnosis and increasing life expectancy. Adult patients uniquely suffer the manifestations of end-organ damage caused by the disease and its treatment, and transition to adulthood poses specific issues in disease management. To standardize and optimize care for this rare disease, in this review we provide updated guidance on the diagnosis and management of DBA, with a specific focus on older adolescents and adults. Recommendations are based upon published literature and our pooled clinical experience from three centres in the United Kingdom (U·K.). Uniquely we have also solicited and incorporated the views of affected families, represented by the independent patient organization, DBA U.K.

De novo intronic GATA1 mutation leads to diamond-blackfan anemia like disease

GATA1 is required for normal erythropoiesis. Exonic/intronic GATA1 mutations causes Diamond-Blackfan Anemia (DBA)-like disease. Herein, we present a case of a 5-year-old boy with anemia of unknown etiology. Whole-exome sequencing revealed a de novo GATA1 c.220 + 1G>C mutation. The reporter gene assay revealed that such mutations did not affect on GATA1 transcriptional activity. The normal transcription of GATA1 was disturbed, as evidenced by increased expression of the shorter GATA1 isoform. RDDS prediction analysis revealed that abnormal GATA1 splicing might be the underlying mechanism disrupting GATA1 transcription, thereby impairing erythropoiesis. Prednisone treatment significantly improved erythropoiesis, evidenced by increased hemoglobin and reticulocyte counts.

Diamond-Blackfan anaemia caused by a de novo initiation codon mutation resulting in a shorter isoform of GATA1

Diamond-Blackfan Anaemia (DBA) is an inherited marrow failure disorder characterised by selective erythroid aplasia. Herein, we reported a case of DBA caused by a novel GATA1 gene mutation. The proband manifested normocytic normochromic anaemia, while the parents were asymptomatic. Next-generation sequencing identified a novel de novo mutation at GATA1 initiation codon (GATA1:c.3G>A) in the proband. The mutation led to a shortened GATA1 protein (GATA1s), which caused a reduction in full-length functional GATA1 protein (GATA1fl). This is the first report of GATA1-related DBA patient in the East Asian population, which expanded the mutational spectrum of DBA furthering understanding of its pathogenesis.