Diamond-Blackfan Research Articles

Regulated GATA1 expression as a universal gene therapy for Diamond-Blackfan anemia.

Gene therapy using hematopoietic stem and progenitor cells is altering the therapeutic landscape for patients with hematologic, immunologic, and metabolic disorders but has not yet been successfully developed for individuals with the bone marrow failure syndrome Diamond-Blackfan anemia (DBA). More than 30 mutations cause DBA through impaired ribosome function and lead to inefficient translation of the erythroid master regulator GATA1, providing a potential avenue for therapeutic intervention applicable to all patients with DBA, irrespective of the underlying genotype. Here, we report the development of a clinical-grade lentiviral gene therapy that achieves erythroid lineage-restricted expression of GATA1. We show that this vector is capable of augmenting erythropoiesis in DBA models and diverse patient samples without impacting hematopoietic stem cell function or demonstrating any signs of premalignant clonal expansion. These preclinical safety and efficacy data provide strong support for the first-in-human universal gene therapy trial for DBA through regulated GATA1 expression.

Case report: Rethinking NGS analysis in diagnosing Diamond-Blackfan anemia syndrome

Diamond-Blackfan anemia syndrome (DBAS) is a rare inherited bone marrow failure (BMF) syndrome characterized by erythroid aplasia, congenital malformations, and cancer predisposition. With its genetic heterogeneity, variable penetrance and expressivity, DBAS poses significant diagnostic challenges, necessitating advancements in genetic testing for improved accuracy. Here, we present the case of an 18-year-old male with a long-standing macrocytic anemia that remained undiagnosed despite standard whole exome sequencing (WES). Revisiting a family-trio WES analysis with clinical insight led to the identification of a likely pathogenic variant in the Ribosomal Protein S17 (RPS17) gene, previously masked due to analytical challenges and conservative filter settings. This variant, an initiation codon mutation, was confirmed in heterozygosity in both the proband and his mother through Sanger sequencing. Comprehensive imaging studies showed no malformations or organ anomalies in either individual, except for mild esophageal stenosis observed in both. RPS17 mutations, particularly those affecting the initiation codon, have previously been linked to the DBAS phenotype, but strong pathogenic association has not yet been firmly established. Our case warns of potential underdiagnosis of RPS17 variants in DBAS, highlighting the importance of clinical context and interdisciplinary collaboration in interpreting WES data to avoid false-negative results.

Haematopoietic cell transplantation for 106 infants and preschoolers with acquired and inherited bone marrow failures.

Aplastic anaemia in infants and young children presents unique challenges due to high prevalence of inherited bone marrow failure syndromes (IBMFS) in this age group. The objective of this study is assessing clinical characteristics and outcomes of haematopoietic cell transplantation in children ≤5 years with bone marrow failure syndromes. We analysied 106 patients (66% males), median age 4.6 years, including 40 with Fanconi anaemia (FA), 32 with Acquired Severe Aplastic anaemia (aSAA), 15 with Diamond-Blackfan Anaemia, 11 with Amegakaryocytic Purpura and 8 with other IBMFS. Molecular testing was limited (39%), with 25.4% confirmed genetically. Retrospective longitudinal study across three paediatric transplantation centres (1982-2020). Overall survival (OS) was 76.4% over a median 10-year follow-up. OS rates were similar between aSAA and IBMFS (FA 77.5%, other IBMFS 76.5%). Transplant-related mortality (TRM) was lower in aSAA (9.4%) compared with IBMFS (16.2%). Recent years showed improved outcomes, with TRM declining post-2010. Choice of stem cell source impacted OS, favouring bone marrow over umbilical cord, but showing encouraging results with haploidentical. Late complications were common, including endocrine-metabolic issues and delayed neuropsychomotor development. Diagnosing and managing bone marrow failures in young children pose significant challenges. Despite advancements in transplant practices, ongoing vigilance and comprehensive care are necessary to improve long-term survival rates.

Genotype‐phenotype associations in individuals with Diamond Blackfan anaemia

AbstractIntroductionDiamond Blackfan anaemia (DBA) is a rare disorder characterized by failure of red blood cell production, congenital abnormalities and cancer predisposition, primarily caused by pathogenic germline variants in genes encoding ribosomal proteins.MethodsWe conducted a genotype‐phenotype and outcome study of 121 patients with DBA spanning the 20‐year history of the National Cancer Institute's Inherited Bone Marrow Failure Syndromes study. Patient phenotypes were compared by large versus small ribosomal protein genes, across genes with >5 cases (RPS19, RPS29, RPS26 and RPL35A) and by type of pathogenic variants (hypomorphic versus null, large deletions versus others).ResultsA pathogenic germline variant was identified in 71% of patients (n = 86/121) from 54 families. After adjusting for multiple testing, we found that patients with RPS29 variants were least likely to need treatment for anaemia while those with large ribosomal protein subunit variants had a higher proportion of intellectual disability and gastrointestinal abnormalities compared with small ribosomal protein subunit variants (p < 3.5 × 10−4). There were no statistically significant differences in overall survival or cancer incidence among patients with large or small ribosomal subunit genes.ConclusionThis detailed genotype‐phenotype study of DBA improves our understanding of the role of germline genetics in the clinical manifestations that may help guide the management of people with DBA.

RPS19 and RPL5, the most commonly mutated genes in Diamond Blackfan anemia, impact DNA double-strand break repair.

Diamond Blackfan anemia (DBA) is caused by germline heterozygous loss-of-function pathogenic variants (PVs) in ribosomal protein (RP) genes, most commonly RPS19 and RPL5 . In addition to red cell aplasia, individuals with DBA are at increased risk of various cancers. Importantly, the mechanism(s) underlying cancer predisposition are poorly understood. We found that DBA patient-derived lymphoblastoid cells had persistent γ-H2AX foci following ionizing radiation (IR) treatment, suggesting DNA double-strand break (DSB) repair defects. RPS19- and RPL5-knocked down (KD) CD34+ cells had delayed repair of IR-induced DSBs, further implicating these RPs in DSB repair. Assessing the impact of RPS19- and RPL5-KD on specific DSB repair pathways, we found RPS19-KD decreased the efficiency of pathways requiring extensive end-resection, whereas RPL5-KD increased end-joining pathways. Additionally, RAD51 was reduced in RPS19- and RPL5-KD and RPS19- and RPL5-mutated DBA cells, whereas RPS19-deficient cells also had a reduction in PARP1 and BRCA2 proteins. RPS19-KD cells had an increase in nuclear RPA2 and a decrease in nuclear RAD51 foci post-IR, reflective of alterations in early, critical steps of homologous recombination. Notably, RPS19 and RPL5 interacted with poly(ADP)-ribose chains noncovalently, were recruited to DSBs in a poly(ADP)-ribose polymerase activity-dependent manner, and interacted with Ku70 and histone H2A. RPL5's recruitment, but not RPS19's, also required p53, suggesting that RPS19 and RPL5 directly participate in DSB repair via different pathways. We propose that defective DSB repair arising from haploinsufficiency of these RPs may underline the cancer predisposition in DBA.

Improving precision base editing of the zebrafish genome by Rad51DBD-incorporated single-base editors

Single-base editors, including cytosine base editors (CBEs) and adenine base editors (ABEs), facilitate accurate C⋅G to T⋅A and A⋅T to G⋅C, respectively, holding promise for the precise modeling and treatment of human hereditary disorders. Efficient base editing and expanded base conversion range have been achieved in human cells through base editors fusing with Rad51 DNA binding domain (Rad51DBD) such as hyA3A-BE4max. Here, we show that hyA3A-BE4max catalyzes C-to-T substitution in the zebrafish genome and extends editing positions (C12–C16) proximal to the protospacer adjacent motif. We develop the codon-optimized counterpart zhyA3A-CBE5, which exhibits substantially high C-to-T conversion with 1.59- to 3.50-fold improvement compared to the original hyA3A-BE4max. With these tools, disease-relevant hereditary mutations can be more efficaciously generated in zebrafish. We introduce human genetic mutation rpl11Q42∗ and abcc6aR1463C by zhyA3A-CBE5 in zebrafish, mirroring Diamond-Blackfan anemia and Pseudoxanthoma Elasticum, respectively. Our study expands the base editing platform targeting the zebrafish genomic landscape and the application of single-base editors for disease modeling and gene function study.

Biallelic variation in the choline and ethanolamine transporter FLVCR1 underlies a severe developmental disorder spectrum

PurposeFLVCR1 encodes a solute carrier protein implicated in heme, choline, and ethanolamine transport. Although Flvcr1−/− mice exhibit skeletal malformations and defective erythropoiesis reminiscent of Diamond-Blackfan anemia (DBA), biallelic FLVCR1 variants in humans have previously only been linked to childhood or adult-onset ataxia, sensory neuropathy, and retinitis pigmentosa. MethodsWe identified individuals with undiagnosed neurodevelopmental disorders and biallelic FLVCR1 variants through international data sharing and characterized the functional consequences of their FLVCR1 variants. ResultsWe ascertained 30 patients from 23 unrelated families with biallelic FLVCR1 variants and characterized a novel FLVCR1-related phenotype: severe developmental disorders with profound developmental delay, microcephaly (z-score −2.5 to −10.5), brain malformations, epilepsy, spasticity, and premature death. Brain malformations ranged from mild brain volume reduction to hydranencephaly. Severely affected patients share traits, including macrocytic anemia and skeletal malformations with Flvcr1−/− mice and DBA. FLVCR1 variants significantly reduce choline and ethanolamine transport and/or disrupt mRNA splicing. ConclusionThese data demonstrate a broad FLVCR1-related phenotypic spectrum ranging from severe multiorgan developmental disorders resembling DBA to adult-onset neurodegeneration. Our study expands our understanding of Mendelian choline and ethanolamine disorders and illustrates the importance of anticipating a wide phenotypic spectrum for known disease genes and incorporating model organism data into genome analysis to maximize genetic testing yield.

RPL26 variants: A rare cause of Diamond-Blackfan anemia syndrome with multiple congenital anomalies at the forefront

PurposeDiamond-Blackfan anemia syndrome (DBS) is a rare congenital disorder originally characterized by bone marrow failure with or without various congenital anomalies. At least 24 genes are implicated, the vast majority encoding for ribosomal proteins. RPL26 (ribosomal protein L26) is an emerging candidate (DBA11, MIM#614900). We aim to further delineate this rare condition. MethodsPatients carrying heterozygous RPL26 variants were recruited. In one of them, erythroid proliferation and differentiation from peripheral blood CD34+ cells were studied by flow cytometry, and RPL26 expression by qRT-PCR and immunoblotting. ResultsWe report on 8 affected patients from 4 families. Detailed phenotyping reveals that RPL26 is mainly associated with multiple congenital anomalies (particularly radial ray anomalies), albeit with variable expression. Mandibulofacial dysostosis and neural tube defects are potential features in DBA11, expanding the growing list of DBS abnormalities. In 1 individual, we showed that RPL26 haploinsufficiency was responsible for subclinical impairment in erythroid proliferation and enucleation. The absence of hematological involvement in 4 adults from this series contributes to the mounting evidence that bone marrow failure is not universally central to all DBS genes. ConclusionWe confirm RPL26 as a DBS gene and expand the phenotypic spectrum of the gene and the disease.

An atypical form of 60S ribosomal subunit in Diamond-Blackfan anemia linked to RPL17 variants.

Diamond-Blackfan anemia syndrome (DBA) is a ribosomopathy associated with loss-of-function variants in more than 20 ribosomal protein (RP) genes. Here, we report the genetic, functional, and biochemical dissection of 2 multigenerational pedigrees with variants in RPL17, a large ribosomal subunit protein-encoding gene. Affected individuals had clinical features and erythroid proliferation defects consistent with DBA. Further, RPL17/uL22 depletion resulted in anemia and micrognathia in zebrafish larvae, and in vivo complementation studies indicated that RPL17 variants were pathogenic. Lymphoblastoid cell lines (LCLs) derived from patients displayed a ribosomal RNA maturation defect reflecting haploinsufficiency of RPL17. The proteins encoded by RPL17 variants were not incorporated into ribosomes, but 10%-20% of 60S ribosomal subunits contained a short form of 5.8S rRNA (5.8SC), a species that is marginal in normal cells. These atypical 60S subunits were actively engaged in translation. Ribosome profiling showed changes of the translational profile, but those are similar to LCLs bearing RPS19 variants. These results link an additional RP gene to DBA. They show that ribosomes can be modified substantially by RPL17 haploinsufficiency but support the paradigm that translation alterations in DBA are primarily related to insufficient ribosome production rather than to changes in ribosome structure or composition.

Reduced anti-Müllerian hormone levels in males with inherited bone marrow failure syndromes.

Fanconi anemia (FA), dyskeratosis congenita-related telomere biology disorders (DC/TBD), and Diamond-Blackfan anemia (DBA) are inherited bone marrow failure syndromes (IBMFS) with high risks of bone marrow failure, leukemia, and solid tumors. Individuals with FA have reduced fertility. Previously, we showed low levels of anti-Müllerian hormone (AMH), a circulating marker of ovarian reserve, in females with IBMFS. In males, AMH may be a direct marker of Sertoli cell function and an indirect marker of spermatogenesis. In this study, we assessed serum AMH levels in pubertal and postpubertal males with FA, DC/TBD, or DBA and compared this with their unaffected male relatives and unrelated healthy male volunteers. Males with FA had significantly lower levels of AMH (median: 5 ng/mL, range: 1.18-6.75) compared with unaffected male relatives (median: 7.31 ng/mL, range: 3.46-18.82, P = 0.03) or healthy male volunteers (median: 7.66 ng/mL, range: 3.3-14.67, P = 0.008). Males with DC/TBD had lower levels of AMH (median: 3.76 ng/mL, range: 0-8.9) compared with unaffected relatives (median: 5.31 ng/mL, range: 1.2-17.77, P = 0.01) or healthy volunteers (median: 5.995 ng/mL, range: 1.57-14.67, P < 0.001). Males with DBA had similar levels of AMH (median: 3.46 ng/mL, range: 2.32-11.85) as unaffected relatives (median: 4.66 ng/mL, range: 0.09-13.51, P = 0.56) and healthy volunteers (median: 5.81 ng/mL, range: 1.57-14.67, P = 0.10). Our findings suggest a defect in the production of AMH in postpubertal males with FA and DC/TBD, similar to that observed in females. These findings warrant confirmation in larger prospective studies.

Activation of nemo-like kinase in diamond blackfan anemia suppresses early erythropoiesis by preventing mitochondrial biogenesis

Diamond Blackfan Anemia (DBA) is a rare macrocytic red blood cell aplasia that usually presents within the first year of life. The vast majority of patients carry a mutation in one of approximately 20 genes that results in ribosomal insufficiency with the most significant clinical manifestations being anemia and a predisposition to cancers. Nemo-like Kinase (NLK) is hyperactivated in the erythroid progenitors of DBA patients and inhibition of this kinase improves erythropoiesis, but how NLK contributes to the pathogenesis of the disease is unknown. Here we report that activated NLK suppresses the critical upregulation of mitochondrial biogenesis required in early erythropoiesis. During normal erythropoiesis, mTORC1 facilitates the translational upregulation of Transcription factor A, mitochondrial (TFAM) and Prohibin 2 (PHB2) to increase mitochondrial biogenesis. In our models of DBA, active NLK phosphorylates the regulatory component of mTORC1, thereby suppressing mTORC1 activity and preventing mTORC1-mediated TFAM and PHB2 upregulation and subsequent mitochondrial biogenesis. Improvement of erythropoiesis that accompanies NLK inhibition is negated when TFAM and PHB2 upregulation is prevented. These data demonstrate that a significant contribution of NLK on the pathogenesis of DBA is through loss of mitochondrial biogenesis.

Clinical Profile of Adults with Inherited Bone Marrow Failure Syndromes: Results of an Ambispective Clinical Single-Center Study

BACKGROUND. Inherited bone marrow failure syndromes (IBMFS) is a heterogenous group of rare genetically determined diseases with variable hematologic and nonhematologic manifestations. The implementation of highly specific methods of genetic diagnosis advanced the understanding of IBMFS and allowed its application also beyond pediatrics. That presupposes an awareness of clinical features and reference points for recognizing IBMFS in adults. AIM. To describe the clinical profile of adult IBMFS patients. MATERIALS &amp; METHODS. This ambispective single-center study enrolled 35 patients (10 women and 25 men) with IBMFS. Patients were aged 18–51 years (median 26 years). The following IBMFS were identified: congenital dyskeratosis (n = 10; 28 %), Diamond-Blackfan anemia (n = 9; 26 %), Fanconi anemia (n = 7; 20 %), GATA2 deficiency (n = 3; 8 %), Shwachman-Diamond syndrome (n = 1; 3 %), GATA2 deficiency (n = 1; 3 %), amegakaryocytic thrombocytopenia (n = 1; 3 %), bone marrow failure syndrome type 3 (n = 1; 3 %), severe congenital neutropenia (n = 1; 3 %), bone marrow failure with SAMD9 mutation (n = 1; 3 %). These diseases were analyzed in terms of hematologic and nonhematologic manifestations as well as main diagnosis stages and factors that contribute to recognizing IBMFS. RESULTS. Monolinear cytopenia, bilinear cytopenia, and pancytopenia were identified at hematologic onset in 18 (52 %), 6 (17 %), and 11 (31 %) patients, respectively. The median age of patients by hematologic onset was 15 years (range 0–43 years), in 14 (40 %) patients cytopenia was newly diagnosed at the age of &gt; 18 years. In 23 (63 %) patients hypocellular bone marrow was reported, 7 (20 %) and 5 (14 %) patients had pure red cell aplasia and multilineage myelodysplasia, respectively. Chromosomal aberrations were identified in 2 patients. Paroxysmal nocturnal hemoglobinuria clone was detected in none of 27 examined patients. In 12 (34 %) patients, the criteria for non-severe aplastic anemia were met. Temporary partial or complete spontaneous hematologic recovery was observed in 6 (17 %) patients. Abnormalities with partial or complete organ dysfunctions were identified in 14 patients, whereas all patients showed minor congenital defects. All 7 Fanconi anemia patients and 9 out of 10 congenital dyskeratosis patients demonstrated organ damage specific to these diseases. Family history predominantly showing malignant neoplasms in relatives was reported in 15 (43 %) patients. Initial hematological examination yielded suspect of IBMFS in 12 (34 %) patients with the median time to diagnosis of 6 months. In 23 (66 %) patients, hematologic defects with cytopenia were erroneously accounted for by various acquired diseases, which led to a delayed correct diagnosis (median 7 years). The key factors in suspecting IBMFS were organ abnormalities and positive family history. The IBMFS diagnosis was verified by the next-generation sequencing (NGS) in 29 (83 %) patients and by other specific methods in 4 (11 %) patients. In 2 patients, the diagnosis was established on the basis of complete clinical criteria alone. CONCLUSION. IBMFS is a matter of current concern and a difficult-to-recognize clinical challenge in adult hematology patients. Differential diagnosis of acquired and congenital bone marrow failure needs to be performed irrespective of patient’s age. A detailed physical examination of patients, family history, and critical analysis of clinical profile and disease course allow for early suspicion of IBMFS. Suspected IBMFS is an indication for referral of patients to specialized centers and performing genetic diagnostics including NGS.

Generation of iPSC lines and isogenic gene-corrected lines from two individuals with RPS19-mutated Diamond-Blackfan anemia syndrome

Diamond-Blackfan anemia syndrome (DBAS) is an inherited bone marrow failure disorder that typically presents in infancy as hypoplastic anemia and developmental abnormalities in approximately 50% of cases. DBAS is caused by haploinsufficiency in one of 24 ribosomal protein genes, with RPS19 mutations accounting for 25% of cases. We generated iPSC lines from two patients with different heterozygous RPS19 mutations (c.191T > C and c.184C > T) and isogenic lines in which the mutations were corrected by Cas9-mediated homology directed repair.

Associated Congenital Abnormalities and Physical Phenotype in Patients with Diamond-Blackfan Anemia May Be Overlooked.

Diamond-Blackfan anemia (DBA) is a rare and inherited form of erythroid aplasia, characterized by severe macrocytic anemia, congenital malformations, and predisposition to cancer. The purpose of this study is to determine the congenital abnormalities and dysmorphological features of DBA patients in a cross-sectional manner. The study group included patients who had diagnosis of DBA between 1983 and 2017. Dysmorphological examinations of the patients were performed by an experienced dysmorphologist and also echocardiography and abdominal ultrasonography were performed in order to figure out cardiac and urogenital abnormalities. A total of 45 patients were examined in this study. Dysmorphological examination, echocardiography, and abdominal ultrasonography revealed the rate of congenital abnormalities as high as 88.7%. In consideration of the congenital abnormalities, the most common findings were craniofacial, followed by skeletal abnormalities. The rate of anomalies was found higher in our series of patients than that have been previously reported, most probably due to the evaluations being performed by a dysmorphologist in our cohort and not only depending on patient records or hematologists' physical examination.

ДИФФЕРЕНЦИАЛЬНАЯ ДИАГНОСТИКА ПРИОБРЕТЕННОЙ АПЛАСТИЧЕСКОЙ АНЕМИИ У ДЕТЕЙ: АНАЛИЗ ДАННЫХ РЕГИСТРОВОГО ИССЛЕДОВАНИЯ

Acquired aplastic anemia (AA) is still the diagnosis of exclusion. The purpose of the research was to identify clinical and laboratory signs that do not correspond to acquired AA allowing to diagnose other diseases accompanied by cytopenia. Materials and methods used: Authors represent the results of diagnostic search in pediatric patients (0 to 18 y/o) with a suspected diagnosis of acquired AA who underwent remote diagnosis in the laboratories of the National Scientific and Practical Center for Pediatric Hematology, Oncology and Immunology named after Dmitry Rogachev (Moscow, Russia) as part of the Register Study in Sep. 1, 2017-May 1, 2022. Results: in retrospective analysis of 523 children records, 104 (20%) patients had other diagnoses. In 29 (27.9%) patients were diagnosed with inherited bone marrow failure syndromes (IBMFS), in 11 (10.6%) with myelodysplastic syndrome, in 11 (10.6%) with deficiency anemia, in 10 (9.6%) with congenital unspecified AA, in 7 (6.7%) with immune cytopenia, in 7 (6.7%) with inborn defects of immunity, in 6 (5.8%) with secondary AA, in 6 (5.8%) with acute leukemia, in 2 (1.9%) with paroxysmal nocturnal hemoglobinuria and in 15 (14.4%) cases with other unspecified diseases. Fanconi anemia (n=15/29 patients) was the most common disease in the IBMFS group; this group had also included: dyskeratosis congenita (n=9), Schwachman-Diamond syndrome (n=2), amegakaryocytic thrombocytopenia (n=2), Diamond-Blackfan anemia in combination with congenital neutropenia (n=1). Conclusion: differential diagnosis of acquired AA can be difficult though it is undoubtedly must-do for successful treatment. Verification of other alternative diseases, including genetically determined syndromes, contributes to the choice of optimal patient management tactics.

Overexpression of human SAMD9 inhibits protein translation and alters MYC signaling resulting in cell cycle arrest

Inherited bone marrow failure syndromes often result from pathogenic mutations in genes that are important for ribosome function, namely, Diamond-Blackfan anemia, Shwachman-Diamond syndrome, and dyskeratosis congenita. Germline mutations in SAMD9 are a frequent genetic lesion resulting in an inherited bone marrow failure syndrome with monosomy 7; some patients have severe multisystem syndromes that include myelodysplasia. The association of germline SAMD9 mutations and bone marrow failure is clear; however, to date, there is no reliable method to predict whether a novel SAMD9 mutation is pathogenic unless it is accompanied by an obvious family history and/or clinical syndrome. The difficulty with pathogenicity prediction is, in part, due to the incomplete understanding of the biological functions of SAMD9. We used a SAMD9-targeted, inducible CRISPRa system and RNA sequencing to better understand the global transcriptional changes that result from transcriptional manipulation of SAMD9. Supporting recent discoveries that SAMD9 acts as a ACNase specific for phenylalanine tRNA (tRNA-Phe), we confirmed with crosslinking and solid-phase purification that SAMD9 is an RNA binding protein and analyzed how overexpression of tRNA-Phe may reverse transcriptomic changes caused by SAMD9 activation. Our data show that overexpression of SAMD9 from the endogenous locus results in decreased cell proliferation, cell cycle progression, and global protein translation. When SAMD9 contains a gain-of-function mutation (p.E1136Q), these functional phenotypes are exacerbated but only partially rescued with tRNA-Phe overexpression, suggesting additional molecular actions of SAMD9. Additionally, we demonstrate that gene expression pathways important for ribosome biogenesis and MYC signaling are the most significantly impacted by SAMD9 overexpression.

Towards a Cure for Diamond-Blackfan Anemia: Views on Gene Therapy.

Diamond-Blackfan anemia (DBA) is a rare genetic disorder affecting the bone marrow's ability to produce red blood cells, leading to severe anemia and various physical abnormalities. Approximately 75% of DBA cases involve heterozygous mutations in ribosomal protein (RP) genes, classifying it as a ribosomopathy, with RPS19 being the most frequently mutated gene. Non-RP mutations, such as in GATA1, have also been identified. Current treatments include glucocorticosteroids, blood transfusions, and hematopoietic stem cell transplantation (HSCT), with HSCT being the only curative option, albeit with challenges like donor availability and immunological complications. Gene therapy, particularly using lentiviral vectors and CRISPR/Cas9 technology, emerges as a promising alternative. This review explores the potential of gene therapy, focusing on lentiviral vectors and CRISPR/Cas9 technology in combination with non-integrating lentiviral vectors, as a curative solution for DBA. It highlights the transformative advancements in the treatment landscape of DBA, offering hope for individuals affected by this condition.

Un caso di anemia macrocitica non megaloblastica: la sindrome di Blackfan Diamond

The case of a two-year-old child with severe isolated anaemia (6 g%) and marked macrocytosis, ultimately diagnosed as Blackfan-Diamond syndrome, is described. The genetic, clinical and prognostic aspects of the disease are briefly discussed.

Lentivirus-mediated gene therapy corrects ribosomal biogenesis and shows promise for Diamond Blackfan anemia.

This study lays the groundwork for future lentivirus-mediated gene therapy in patients with Diamond Blackfan anemia (DBA) caused by mutations in ribosomal protein S19 (RPS19), showing evidence of a new safe and effective therapy. The data show that, unlike patients with Fanconi anemia (FA), the hematopoietic stem cell (HSC) reservoir of patients with DBA was not significantly reduced, suggesting that collection of these cells should not constitute a remarkable restriction for DBA gene therapy. Subsequently, 2 clinically applicable lentiviral vectors were developed. In the former lentiviral vector, PGK.CoRPS19 LV, a codon-optimized version of RPS19 was driven by the phosphoglycerate kinase promoter (PGK) already used in different gene therapy trials, including FA gene therapy. In the latter one, EF1α.CoRPS19 LV, RPS19 expression was driven by the elongation factor alpha short promoter, EF1α(s). Preclinical experiments showed that transduction of DBA patient CD34+ cells with the PGK.CoRPS19 LV restored erythroid differentiation, and demonstrated the long-term repopulating properties of corrected DBA CD34+ cells, providing evidence of improved erythroid maturation. Concomitantly, long-term restoration of ribosomal biogenesis was verified using a potentially novel method applicable to patients' blood cells, based on ribosomal RNA methylation analyses. Finally, in vivo safety studies and proviral insertion site analyses showed that lentivirus-mediated gene therapy was nontoxic.

Integrated proteogenomic analysis for inherited bone marrow failure syndrome.

Recent advances in in-depth data-independent acquisition proteomic analysis have enabled comprehensive quantitative analysis of >10,000 proteins. Herein, an integrated proteogenomic analysis for inherited bone marrow failure syndrome (IBMFS) was performed to reveal their biological features and to develop a proteomic-based diagnostic assay in the discovery cohort; dyskeratosis congenita (n = 12), Fanconi anemia (n = 11), Diamond-Blackfan anemia (DBA, n = 9), Shwachman-Diamond syndrome (SDS, n = 6), ADH5/ALDH2 deficiency (n = 4), and other IBMFS (n = 18). Unsupervised proteomic clustering identified eight independent clusters (C1-C8), with the ribosomal pathway specifically downregulated in C1 and C2, enriched for DBA and SDS, respectively. Six patients with SDS had significantly decreased SBDS protein expression, with two of these not diagnosed by DNA sequencing alone. Four patients with ADH5/ALDH2 deficiency showed significantly reduced ADH5 protein expression. To perform a large-scale rapid IBMFS screening, targeted proteomic analysis was performed on 417 samples from patients with IBMFS-related hematological disorders (n = 390) and healthy controls (n = 27). SBDS and ADH5 protein expressions were significantly reduced in SDS and ADH5/ALDH2 deficiency, respectively. The clinical application of this first integrated proteogenomic analysis would be useful for the diagnosis and screening of IBMFS, where appropriate clinical screening tests are lacking.