Inherited bone marrow failure syndromes: considerations pre- and posttransplant

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.

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.

Optimizing diagnostic methods and stem cell transplantation outcomes in pediatric bone marrow failure: a 50-year single center experience

Peripheral blood cytopenia, a frequent presenting symptom in pediatric patients, can be caused by bone marrow failure (BMF). Timely identification of patients with non-reversible BMF is of crucial importance to reduce the risks of invasive infections and bleeding complications. Most pediatric patients with severe persistent cytopenia, independent of the underlying cause, are offered allogeneic hematopoietic stem cell transplantation (HSCT) as curative therapy. Here we report on our management guidelines and HSCT outcomes of pediatric BMF patients to pinpoint improvements and future challenges. We formulated recommendations based on this 50 years' experience, which were implemented at our center in 2017. By analysis of the HSCT cohort of 2017-2023, the 5-year outcome data is presented and compared to historical outcome data. In addition, outcomes of patients transplanted for identified inherited bone marrow failure syndromes (IBMFS) are compared to severe aplastic anemia (SAA) outcomes to underline the often multiorgan disease in IBMFS with implications for long-term survival. Survival of pediatric patients with irreversible BMF has improved tremendously. SAA patients transplanted after 2017 had a superior 5-year overall (OS) and event-free survival (EFS) of 97% and 85% compared to 68% and 59% in the cohort transplanted before 2017 (p = 0.0011 and p = 0.017). A similar trend was seen for BMF, with an OS and EFS of 89% for those transplanted after 2017 compared to 62% and 59% (p > 0.05). This improvement is mainly related to better survival in the first months after HSCT. The long-term survival after HSCT is lower in IBMFS patients as compared to SAA patients due to secondary malignancies and multiorgan toxicity.   Conclusion: Unbiased protocolized in-depth diagnostic strategies are crucial to increase the frequency of identifiable causes within the heterogeneous group of pediatric BMF. A comprehensive approach to identify the cause of BMF can prevent treatment delay and be useful to tailor treatment and follow-up protocols. What is Known: • Irreversible BMF in pediatric patients can be caused by a wide spectrum of underlying diseases including (pre)malignant disease, IBMFS and AA. Identifying the exact underlying cause of BMF is crucial for tailored therapy, however often challenging and time-consuming. • Frontline allogeneic HSCT is offered to most pediatric patients with severe BMF as curative treatment. What is New: • Protocolized unbiased diagnostics, short time to treatment (< 3 months) and maximal supportive care until curative treatment can prevent complications with a negative effect on survival such as infection and bleeding. • Personalized follow-up protocols for IBMFS patients are essential to prevent a second decline in survival due to long-term treatment toxicity and extra-hematological disease complications.

Fludarabine-based Reduced Intensity Conditioning for Allogeneic Hematopoietic Stem Cell Transplantation in a Pediatric Patient With Bone Marrow Failure Syndrome Type 3

Bone marrow failure syndrome (BMFS) type 3 is a rare genetic heterogeneous disorder, considered to be one of Inherited BMFSs related to ribosomopathies. It caused by a novel Homozygous variant in DNAJC21 gene, which affects cytoplasmic maturation of 60S ribosomal, leading to increase cell death, and inhibits cellular proliferation causing shwachman-diamond Syndrome-like syndrome. Only 15 cases of BMFS type 3 have been published in the literature. Therefore, the full phenotypic spectrum and the experience of hematopoietic stem cell transplantation (HSCT) are limited. Herein, we report an uncomplicated HSCT from human leukocyte antigen-identical sibling for a BMFS-3 patient at 22 months of age, who suffered from chronic diarrhea, severe failure to thrive and cytopenia required transfusions. We used a reduced intensity conditioning regimen including fludarabine, low-dose cyclophosphamide, and antithymocyte globulin with cyclosporine for prevent graft versus host disease. This regimen was safe and sufficient to achieve rapid engraftment without significant toxicity. Although, Mixed chimerism between 80% and 90% was observed since day +30, she gained 2 kg during 12 months post-transplant and no need for transfusions has been reported any more. Thus, we recommend HSCT with fludarabine-based reduced intensity conditioning regimen in this syndrome as progressive cytopenia occurs and an human leukocyte antigen-matched family donor is available.

A Promising Insight: The Potential Influence and Therapeutic Value of the Gut Microbiota in GI GVHD

Allogeneic hematopoietic cell transplantation (allo-HSCT) is a reconstruction process of hematopoietic and immune functions that can be curative in patients with hematologic malignancies, but it carries risks of graft-versus-host disease (GVHD), thrombotic microangiopathy (TMA), Epstein–Barr virus (EBV) infection, cytomegalovirus infection, secondary hemophagocytic lymphohistiocytosis (sHLH), macrophage activation syndrome (MAS), bronchiolitis obliterans, and posterior reversible encephalopathy syndrome (PRES). Gastrointestinal graft-versus-host disease (GI GVHD), a common complication of allo-HSCT, is one of the leading causes of transplant-related death because of its high treatment difficulty, which is affected by preimplantation, antibiotic use, dietary changes, and intestinal inflammation. At present, human trials and animal studies have proven that a decrease in intestinal bacterial diversity is associated with the occurrence of GI GVHD. Metabolites produced by intestinal bacteria, such as lipopolysaccharides, short-chain fatty acids, and secondary bile acids, can affect the development of GVHD through direct or indirect interactions with immune cells. The targeted damage of GVHD on intestinal stem cells (ISCs) and Paneth cells results in intestinal dysbiosis or dysbacteriosis. Based on the effect of microbiota metabolites on the gastrointestinal tract, the clinical treatment of GI GVHD can be further optimized. In this review, we describe the mechanisms of GI GVHD and the damage it causes to intestinal cells and we summarize recent studies on the relationship between intestinal microbiota and GVHD in the gastrointestinal tract, highlighting the role of intestinal microbiota metabolites in GI GVHD. We hope to elucidate strategies for immunomodulatory combined microbiota targeting in the clinical treatment of GI GVHD.

Kidney complications in 107 Fanconi anemia patients submitted to hematopoietic cell transplantation

Fanconi anemia (FA) is a rare disease characterized by progressive bone marrow failure, cancer predisposition, and multiple systemic malformations, including congenital abnormalities of the kidney and urinary tract (CAKUT). Hematopoietic cell transplantation (HCT), the only potentially curative treatment for the hematological complications of FA, may precipitate acute kidney injury (AKI) and hypertension. We retrospectively investigated 107 FA patients who underwent HCT between 2009 and 2017. We investigated the incidence and risk factors of AKI within 100 days after HCT in a cohort of FA patients, and kidney function and hypertension over 2-year follow-up.The incidence of AKI (mainly stage I) was 18.7%. Patients aged ≥ 11 years at transplantation showed a higher risk of AKI (OR 3.53). The eGFR was 60-90 mL/min/1.73 m² in 53 (49.5%), 55 (51.4%), 50 (50.5%), 50 (51%), and 46 (59.7%) patients before HCT, at 100 days, 6 months, 1 year, and 2 years. Within the first 100 days after HCT, hypertension was observed in 72% of the patients and was associated with cyclosporine therapy. Most (62.3%) patients had stage 2 hypertension. CAKUT was observed in 33.7% of the patients and was associated with both hypertension (86%) and diminished kidney function but not with AKI.Conlusion: Although AKI, a commonly known HCT complication, was mild in this study, the prevalence of chronic kidney disease (CKD), as well as the high incidence of hypertension, specially associated with CAKUT point out the importance of kidney care in short and long-term follow up of FA patients. What is Known: • Fanconi anemia (FA) is the most frequent inherited bone marrow failure in children, and 30% of cases have congenital anomalies of kidney (CAKUT). • Acute kidney injury and hypertension after hematopoietic cell transplantation (HCT) may impact the outcomes.. What is New: • Despite the presence of CAKUT and stage 2 CKD in 33.7% and 50% of the patients, respectively, AKI was mild and transitory after HCT in FA patients. • CAKUT in FA patients was associated with lower kidney function and hypertension after HCT.

Successful allogeneic stem cell transplantation with fludarabine-based reduced intensity conditioning in bone marrow failure syndrome 4

BACKGROUND

Myb-like, SWIRM, and MPN domains 1 (MYSM1) is a histone H2A deubiquitinase, has been discovered as one of the transcriptional regulators, and regulates the expression of specific transcription factors, which are essential for immunohematology development. Mutation in MYSM1 in humans leads to a rare autosomal recessive disease that has recently been known as inherited bone marrow failure syndrome 4 (BMFS4) associated with congenital bone marrow failure, immunodeficiency, and developmental aberrations. Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative option for immunohematology defects.

METHODS

In this paper, we report a pediatric patient with BMFS4 who suffered from pancytopenia and immunodeficiency affecting B cells and was successfully treated with HSCT from an HLA-identical father at 6 years old of age. Fludarabine-based reduced intensity conditioning was used and resulted in full donor chimerism.

RESULTS

Acute graft versus host disease (GVHD) grade II involving skin and gastrointestinal tract was observed, which was controlled with prednisolone.

CONCLUSION

She achieved B-cell recovery, and no blood or platelet transfusion was reported 1 year after HSCT.

Integrating germline variant assessment into routine clinical practice for myelodysplastic syndrome and acute myeloid leukaemia: current strategies and challenges

Over the last decade, the field of hereditary haematological malignancy syndromes (HHMSs) has gained increasing recognition among clinicians and scientists worldwide. Germline mutations now account for almost 10% of adult and paediatric myelodysplasia/acute myeloid leukaemia (MDS/AML). As our ability to diagnose HHMSs has improved, we are now faced with the challenges of integrating these advances into routine clinical practice for patients with MDS/AML and how to optimise management and surveillance of patients and asymptomatic carriers. Discoveries of novel syndromes combined with clinical, genetic and epigenetic profiling of tumour samples, have highlighted unique patterns of disease evolution across HHMSs. Despite these advances, causative lesions are detected in less than half of familial cases and evidence-based guidelines are often lacking, suggesting there is much still to learn. Future research efforts are needed to sustain current momentum within the field, led not only by advancing genetic technology but essential collaboration between clinical and academic communities.

Treatment of telomeropathies

Telomeropathies or telomere biology disorders (TBDs) are a group of rare diseases characterised by altered telomere maintenance. Most patients with TBDs show pathogenic variants of genes that encode factors involved in the prevention of telomere shortening. Particularly in adults, TBDs mostly present themselves with heterogeneous clinical features that often include bone marrow failure, hepatopathies, interstitial lung disease and other organ sites. Different degrees of severity are also observed among patients with TBDs, ranging from very severe syndromes manifesting themselves in early childhood, such as Revesz syndrome, Hoyeraal-Hreidarsson syndrome, and Coats plus disease, to dyskeratosis congenita (DKC) and adult-onset "cryptic" forms of TBD, which often affect fewer organ systems. Overall, the most relevant clinical complications of TBD are bone marrow failure, lung fibrosis, and liver cirrhosis. In this review, we summarise recent advances in the management and treatment of TBD and provide a brief overview of the various treatment approaches.

Haploidentical Hematopoietic Cell Transplantation Using Post-transplant Cyclophosphamide for Children with Non-malignant Diseases

Haploidentical hematopoietic cell transplantation (HCT) is a valuable curative option for children with non-malignant diseases. Haploidentical HCT using post-transplant cyclophosphamide (PTCy) is a readily available option in the absence of an HLA-matched donor. We conducted a retrospective single-center study on the outcome of haploidentical HCT in children with non-malignant diseases. We gathered data from 44 patients underwent HCT in the period 2015 to 2020. The indications for HCT were bone marrow failure, primary immunodeficiency, metabolic disorders, and hemoglobinopathy. Median age at HCT was 4 years (range 0.7-20). The conditioning regimens were myeloablative (n = 17) or reduced intensity (n = 27). After a median follow-up of 20 months (range 4-71), 2-year overall survival was 89% and 2-year GvHD-free relapse-free survival (GRFS) was 66%. Incidence of primary graft failure was 13.6%. Cumulative incidence of grade II-IV acute and moderate/severe chronic GvHD were 20% and 6.4%, respectively. Younger age at HCT (< 4 years) and primary immunodeficiency were significantly associated with better GRFS (p < 0.05). In conclusion, haploidentical HCT using PTCy is feasible and curative in children with non-malignant diseases lacking an HLA-matched donor. Early diagnosis and referral in addition to timely treatment can further improve outcomes.

Hematopoietic stem cell transplantation for inherited bone marrow failure syndromes: alternative donor and disease-specific conditioning regimen with unmanipulated grafts

Objective: The outcomes of alternative donor hematopoietic stem cell transplantation (HSCT) with unmanipulated grafts for Inherited bone marrow failure syndromes (IBMFS) are discouraging. Our study is to demonstrate that IBMFS with disease-specific characteristics requires a tailored conditioning regimens to enhance engraftment and reduce regimen related toxicities. Methods: We retrospectively analyzed 42 patients diagnosed with IBMFS and transplanted with an alternative donor graft at our center from November 2012 to August 2018. Twenty-seven patients had Fanconi anemia (FA), 7 had dyskeratosis congenita (DC), and 8 had severe congenital neutropenia (SCN). Patients received ex-vivo unmanipulated alternative donor grafts from a matched unrelated donor (MUD) (n = 22), haploidentical donor (HID) (n = 17) and unrelated cord blood donor (UCBD) (n = 3). FA and DC patient subgroups received reduce intensified conditioning (RIC), while SCN patients received a myeloablative conditioning (MAC) regimen. Results: The median follow-up time for the surviving patients was 38 months (range: 9-63 months). The failure-free survival (FFS) for entire cohort was 76.1%, and was 72.4%, 100% and 56.2% for patients with FA, DC and SCN, respectively. There were no primary graft failures. The cumulative incidence of aGVHD at day 100 was 48.1%. The cumulative incidence of cGVHD at 1 and 3 years was 35.0% and 69.3%, respectively. Conclusion: HSCT using alternative donors with unmanipulated grafts and disease-specific conditioning regimens for IBMFS patients shows promising survival.

Cutaneous Squamous Cell Carcinoma in the Age of Immunotherapy

Cutaneous squamous cell carcinoma (cSCC) is the second most prevalent skin cancer globally. Because most cSCC cases are manageable by local excision/radiotherapy and hardly become life-threatening, they are often excluded from cancer registries in most countries. Compared with cutaneous melanoma that originates from the melanin-producing, neural crest-derived epidermal resident, keratinocyte (KC)-derived cancers are influenced by the immune system with regards to their pathogenetic behaviour. Congenital or acquired immunosurveillance impairments compromise tumoricidal activity and raises cSCC incidence rates. Intriguingly, expanded applications of programmed death-1 (PD-1) blockade therapies have revealed cSCC to be one of the most amenable targets, particularly when compared with the mucosal counterparts arisen in the esophagus or the cervix. The clinical observation reminds us that cutaneous tissue has a peculiarly high immunogenicity that can evoke tumoricidal recall responses topically. Here we attempt to redefine cSCC biology and review current knowledge about cSCC from multiple viewpoints that involve epidemiology, clinicopathology, molecular genetics, molecular immunology, and developmental biology. This synthesis not only underscores the primal importance of the immune system, rather than just a mere accumulation of ultraviolet-induced mutations but also reinforces the following hypothesis: PD-1 blockade effectively restores the immunity specially allowed to exist within the fully cornified squamous epithelium, that is, the epidermis.

Diamond-Blackfan anemia

Diamond-Blackfan anemia (DBA) was the first ribosomopathy described and is a constitutional inherited bone marrow failure syndrome. Erythroblastopenia is the major characteristic of the disease, which is a model for ribosomal diseases, related to a heterozygous allelic variation in 1 of the 20 ribosomal protein genes of either the small or large ribosomal subunit. The salient feature of classical DBA is a defect in ribosomal RNA maturation that generates nucleolar stress, leading to stabilization of p53 and activation of its targets, resulting in cell-cycle arrest and apoptosis. Although activation of p53 may not explain all aspects of DBA erythroid tropism, involvement of GATA1/HSP70 and globin/heme imbalance, with an excess of the toxic free heme leading to reactive oxygen species production, account for defective erythropoiesis in DBA. Despite significant progress in defining the molecular basis of DBA and increased understanding of the mechanistic basis for DBA pathophysiology, progress in developing new therapeutic options has been limited. However, recent advances in gene therapy, better outcomes with stem cell transplantation, and discoveries of putative new drugs through systematic drug screening using large chemical libraries provide hope for improvement.

Haploidentical stem cell transplantation with post-transplant cyclophosphamide for osteopetrosis and other nonmalignant diseases

Allogeneic hematopoietic stem cell transplantation (HSCT) is curative for a variety of nonmalignant disorders including osteopetrosis, bone marrow failures, and immune deficiencies. Haploidentical HSCT is a readily available option in the absence of a matched donor, but engraftment failure and other post-transplant complications are a concern. Post-transplant cyclophosphamide (PT-Cy) regimens are gaining popularity and recent reports show promising results. We report our experience with nine pediatric patients with nonmalignant diseases who were transplanted from a haploidentical donor with PT-Cy. From 2015 to 2019, nine children with nonmalignant diseases underwent haploidentical HSCT with PT-Cy, two as a second transplant and seven as primary grafts after upfront serotherapy and busulfan-based myeloablative conditioning. Patient’s diseases included osteopetrosis (n = 5), congenital amegakaryocytic thrombocytopenia (n = 2), hemophagocytic lymphohistiocytosis (n = 1), and Wiskott Aldrich syndrome (n = 1). Two patients failed to engraft following upfront PT-Cy transplants, one was salvaged with a second PT-Cy transplant, and the other with a CD34+ selected graft. None of the patients suffered from graft-versus-host disease. Three patients died from early posttransplant infectious complications and six patients are alive and well. In conclusion, haploidentical HSCT with PT-Cy is a feasible option for pediatric patients with nonmalignant diseases lacking a matched donor.

The Bone's Role in Myeloid Neoplasia

The interaction of hematopoietic stem and progenitor cells with their direct neighboring cells in the bone marrow (the so called hematopoietic niche) evolves as a key principle for understanding physiological and malignant hematopoiesis. Significant progress in this matter has recently been achieved making use of emerging high-throughput techniques that allow characterization of the bone marrow microenvironment at single cell resolution. This review aims to discuss these single cell findings in the light of other conventional niche studies that together define the current notion of the niche's implication in i) normal hematopoiesis, ii) myeloid neoplasms and iii) disease-driving pathways that can be exploited to establish novel therapeutic strategies in the future.

Hereditary Predisposition to Hematopoietic Neoplasms: When Bloodline Matters for Blood Cancers

With the advent of precision genomics, hereditary predisposition to hematopoietic neoplasms- collectively known as hereditary predisposition syndromes (HPS)-are being increasingly recognized in clinical practice. Familial clustering was first observed in patients with leukemia, which led to the identification of several germline variants, such as RUNX1, CEBPA, GATA2, ANKRD26, DDX41, and ETV6, among others, now established as HPS, with tendency to develop myeloid neoplasms. However, evidence for hereditary predisposition is also apparent in lymphoid and plasma--cell neoplasms, with recent discoveries of germline variants in genes such as IKZF1, SH2B3, PAX5 (familial acute lymphoblastic leukemia), and KDM1A/LSD1 (familial multiple myeloma). Specific inherited bone marrow failure syndromes-such as GATA2 haploinsufficiency syndromes, short telomere syndromes, Shwachman-Diamond syndrome, Diamond-Blackfan anemia, severe congenital neutropenia, and familial thrombocytopenias-also have an increased predisposition to develop myeloid neoplasms, whereas inherited immune deficiency syndromes, such as ataxia-telangiectasia, Bloom syndrome, Wiskott Aldrich syndrome, and Bruton agammaglobulinemia, are associated with an increased risk for lymphoid neoplasms. Timely recognition of HPS is critical to ensure safe choice of donors and/or conditioning-regimen intensity for allogeneic hematopoietic stem-cell transplantation and to enable direction of appropriate genomics-driven personalized therapies. The purpose of this review is to provide a comprehensive overview of HPS and serve as a useful reference for clinicians to recognize relevant signs and symptoms among patients to enable timely screening and referrals to pursue germline assessment. In addition, we also discuss our institutional approach toward identification of HPS and offer a stepwise diagnostic and management algorithm.

Comparison of Conventional Cyclophosphamide versus Fludarabine-Based Conditioning in High-Risk Aplastic Anemia Patients Undergoing Matched-Related Donor Transplantation

Allogeneic stem cell transplant for high-risk aplastic anemia (AA) yields inferior results using conventional cyclophosphamide (CY)-based conditioning. The use of fludarabine (Flu)-based regimens has resulted in improved outcomes in high-risk patients. Limited data are available comparing these two conditioning regimens in such patients. We retrospectively analyzed 192 high-risk patients undergoing matched-related donor transplantation from July 2001 to December 2018. The median age was 19.5 (2–52) years. Patients were divided into 2 groups, Cy²⁰⁰ anti-thymocyte globulin (ATG)²⁰ (Gp1 n = 79) or Flu^120–150 Cy^120–160 ATG²⁰ (Gp2 n = 113). The risk of graft failure was significantly higher in Gp1, and the majority occurred in patients with >2 risk factors (p = 0.02). The incidence of grade II-IV acute graft versus host disease (GVHD) and chronic GVHD was not significantly different between the two groups. The overall survival (OS) of the study cohort was 81.3 %, disease-free survival (DFS) 76.6 % and GVHD-free relapse-free survival (GRFS) was 64.1%. DFS and GRFS were significantly higher in Gp2 as compared to Gp1: DFS 84.1% versus 68.4 % (p = 0.02), GRFS 77.9% versus 54.4% (p = 0.01), respectively. We conclude that Flu-based conditioning is associated with superior OS, DFS and GRFS as compared to the conventional Cy-based regimen in high-risk AA.

A General Pediatrician's Approach to Anemia in Childhood

Anemia may be defined as a reduction in red blood cell mass or blood hemoglobin concentration. Physiologically, this represents a hemoglobin level that is too low to meet cellular oxygen demands. Practically, the lower limit of normal is set at 2 standard deviations below the mean based on age, gender, and ethnicity/race. Anemia can lead to impaired growth, development, and poor neurocognitive outcome. As such, it is essential for pediatricians to recognize and conduct appropriate testing for a child with anemia. [Pediatr Ann. 2020;49(1):e10-e16.].

Clinical Applications and Utility of a Precision Medicine Approach for Patients With Unexplained Cytopenias

OBJECTIVE

To demonstrate experience and feasibility of a precision medicine approach for patients with unexplained cytopenias, defined as low blood counts in one or more cell lineages, persistent for 6 months or longer, in the absence of known nutritional, autoimmune, infectious, toxic, and neoplastic (secondary) causes.

PATIENTS AND METHODS

Patients were evaluated in our clinic between November 8, 2016, and January 12, 2018. After a thorough evaluation of known causes, family history, and appropriate clinical assays, genomic evaluation was performed in a stepwise manner, through Sanger, targeted, and/or whole-exome sequencing. Variants were analyzed and discussed in a genomics tumor board attended by clinicians, bioinformaticians, and molecular biologists.

RESULTS

Sixty-eight patients were evaluated in our clinic. After genomic interrogation, they were classified into inherited bone marrow failure syndromes (IBMFS) (n=24, 35%), cytopenias without a known clinical syndrome which included idiopathic and clonal cytopenias of undetermined significance (CCUS) (n=30, 44%), and patients who did not fit into the above two categories ("others," n=14, 21%). A significant family history was found in only 17 (25%) patients (9 IBMFS, 2 CCUS, and 6 others), whereas gene variants were found in 43 (63%) patients (34 [79%] pathogenic including 12 IBMFS, 17 CCUS, and 5 others]. Genomic assessment resulted in a change in clinical management in 17 (25%) patients, as evidenced by changes in decisions with regards to therapeutic interventions (n=8, 47%), donor choice (n=6, 35%), and/or choice of conditioning regimen for hematopoietic stem cell transplantation (n=8, 47%).

CONCLUSION

We show clinical utility of a real-world algorithmic precision medicine approach for unexplained cytopenias.

Medicinal Uses of Hematopoietic Growth Factors in Neonatal Medicine

This review focuses on certain hematopoietic growth factors that are used as medications in clinical neonatology. It is important to note at the chapter onset that although all of the pharmacological agents mentioned in this review have been approved by the US Food and Drug administration for use in humans, none have been granted a specific FDA indication for neonates. Thus, in a sense, all of the agents mentioned in this chapter could be considered experimental, when used in neonates. However, a great many of the pharmacological agents utilized routinely in neonatology practice do not have a specific FDA indication for this population of patients. Consequently, many of the agents reviewed in this chapter are considered by some practitioners to be nonexperimental and are used when they judge such use to be "best practice" for the disorders under treatment.The medicinal uses of the agents in this chapter vary considerably, between geographic locations, and sometimes even within an institutions. "Consistent approaches" aimed at using these agents in uniform ways in the practice of neonatology are encouraged. Indeed some healthcare systems, and some individual NICUs, have developed written guidelines for using these agents within the practice group. Some such guidelines are provided in this review. It should be noted that these guidelines, or "consistent approaches," must be viewed as dynamic and changing, requiring adjustment and refinement as additional evidence accrues.

Differentiation of MISSLA and Fanconi anaemia by computer-aided image analysis and presentation of two novel MISSLA siblings

Variants in DONSON were recently identified as the cause of microcephaly, short stature, and limb abnormalities syndrome (MISSLA). The clinical spectra of MISSLA and Fanconi anaemia (FA) strongly overlap. For that reason, some MISSLA patients have been clinically diagnosed with FA. Here, we present the clinical data of siblings with MISSLA featuring a novel DONSON variant and summarize the current literature on MISSLA. Additionally, we perform computer-aided image analysis using the DeepGestalt technology to test how distinct the facial features of MISSLA and FA patients are. We show that MISSLA has a specific facial gestalt. Notably, we find that also FA patients feature facial characteristics recognizable by computer-aided image analysis. We conclude that computer-assisted image analysis improves diagnostic precision in both MISSLA and FA.

Tumor risk and surveillance for children with hereditary disorders affecting growth

PURPOSE OF REVIEW

Hereditary disorders affecting growth (both overgrowth and growth retardation) are frequently associated with heightened risk of neoplastic disease. This review summarizes the tumor spectra associated with these conditions and identifies disease-specific screening approaches.

RECENT FINDINGS

An understanding of the molecular events underlying many of these growth disorders has evolved significantly over the past several years. Recognition of genotype-phenotype associations, in many cases, informs the cancer risk profile. Additionally, accumulating data suggest a benefit of rational presymptomatic surveillance for at-risk individuals, with a reduction in tumor-associated morbidity. Recent clinical practice recommendations have established risk-driven paradigms for tumor surveillance in the context of hereditary tumor predisposition syndromes, including those affecting growth.

SUMMARY

Clinicians caring for children with growth disorders should be aware of syndromic associations and the associated cancer risks. Knowledge of tumor spectra and recommended surveillance strategies may facilitate tumor diagnosis at an early stage and reduce morbidity of the disease and associated treatments.

An update on the pathogenesis and diagnosis of Diamond-Blackfan anemia

Diamond–Blackfan anemia (DBA) is a rare congenital hypoplastic anemia characterized by a block in erythropoiesis at the progenitor stage, although the exact stage at which this occurs remains to be fully defined. DBA presents primarily during infancy with macrocytic anemia and reticulocytopenia with 50% of cases associated with a variety of congenital malformations. DBA is most frequently due to a sporadic mutation (55%) in genes encoding several different ribosomal proteins, although there are many cases where there is a family history of the disease with varying phenotypes. The erythroid tropism of the disease is still a matter of debate for a disease related to a defect in global ribosome biogenesis. Assessment of biological features in conjunction with genetic testing has increased the accuracy of the diagnosis of DBA. However, in certain cases, it continues to be difficult to firmly establish a diagnosis. This review will focus on the diagnosis of DBA along with a description of new advances in our understanding of the pathophysiology and treatment recommendations for DBA.

Pediatric leukemia susceptibility disorders: manifestations and management

The clinical manifestations of inherited susceptibility to leukemia encompass a wide phenotypic range, including patients with certain congenital anomalies or early-onset myelodysplastic syndrome (MDS) and some with no obvious medical problems until they develop leukemia. Leukemia susceptibility syndromes occur as a result of autosomal dominant, autosomal recessive, or X-linked recessive inheritance, or de novo occurrence, of germline pathogenic variants in DNA repair, ribosome biogenesis, telomere biology, hematopoietic transcription factors, tumor suppressors, and other critical cellular processes. Children and adults with cytopenias, MDS, dysmorphic features, notable infectious histories, immunodeficiency, certain dermatologic findings, lymphedema, unusual sensitivity to radiation or chemotherapy, or acute leukemia with a family history of early-onset cancer, pulmonary fibrosis, or alveolar proteinosis should be thoroughly evaluated for a leukemia susceptibility syndrome. Genetic testing and other diagnostic modalities have improved our ability to identify these patients and to counsel them and their family members for subsequent disease risk, cancer surveillance, and therapeutic interventions. Herein, the leukemia susceptibility syndromes are divided into 3 groups: (1) those associated with an underlying inherited bone marrow failure syndrome, (2) disorders in which MDS precedes leukemia development, and (3) those with a risk primarily of leukemia. Although children are the focus of this review, it is important for clinicians to recognize that inherited susceptibility to cancer can present at any age, even in older adults; genetic counseling is essential and prompt referral to experts in each syndrome is strongly recommended.