Survival after Hematopoietic Stem Cell Transplant in Patients with Dyskeratosis Congenita: Systematic Review of the Literature

Cancer Precursor Syndromes and Their Detection in the Head and Neck

This article explores the multifaceted landscape of oral cancer precursor syndromes. Hereditary disorders like dyskeratosis congenita and Fanconi anemia increase the risk of malignancy. Oral potentially malignant disorders, notably leukoplakia, are discussed as precursors influenced by genetic and immunologic facets. Molecular insights delve into genetic mutations, allelic imbalances, and immune modulation as key players in precancerous progression, suggesting potential therapeutic targets. The article navigates the controversial terrain of management strategies of leukoplakia, encompassing surgical resection, chemoprevention, and immune modulation, while emphasizing the ongoing challenges in developing effective, evidence-based preventive approaches.

Exploration of the potential causative genes for inflammatory bowel disease: Transcriptome-wide association analysis, Mendelian randomization analysis and Bayesian colocalisation

Background

Inflammatory bowel disease (IBD) poses a complex challenge due to its intricate underlying mechanisms, and curative treatments remain elusive. Consequently, there is an urgent need to identify genes causally associated with IBD.

Methods

We extracted blood eQTL data from the GTExv8.ALL.Whole_Blood database, genome-wide association studies (GWAS) summary statistics of IBD from the IEU GWAS database, and performed a three-fold analysis protocol, including transcriptome-wide association analysis, Mendelian randomisation analysis, Bayesian colocalisation, and subsequent potential therapeutic agents identification.

Results

We identified four pathogenic genes, namely CARD9, RTEL1, STMN3 and ARFRP1, that promote the development of IBD, encompassing both ulcerative colitis (UC) and Crohn's disease (CD). Notably, ARFRP1 exhibited the ability to suppress IBD (encompassing UC and CD) development. Regarding drug prediction, cyclophosphamide emerged as a promising novel therapeutic option for IBD, encompassing UC and CD.

Conclusion

We identified several potential genes related to IBD (UC and CD), including CARD9, RTEL1, STMN3 and ARFRP1, warranting further investigation in functional studies to elucidate underlying disease mechanisms. Additionally, clinical studies exploring the potential of cyclophosphamide as a treatment avenue for IBD are warranted.

Posttransplant complications in patients with marrow failure syndromes: are we improving long-term outcomes?

Inherited bone marrow failure syndromes (IBMFS) encompass a group of rare genetic disorders characterized by bone marrow failure, non-hematologic multisystemic comorbidities, disease defining congenital anomalies, and a susceptibility to myelodysplastic syndrome, acute myeloid leukemia, and in some instances solid tumors. The most common IBMFS include Fanconi anemia, Shwachman-Diamond syndrome, Diamond-Blackfan anemia, and telomere biology disorders/ dyskeratosis congenita. Allogeneic hematopoietic stem cell transplant (HCT) is a well-established curative treatment to correct the hematological manifestations but does not halt or reverse the nonhematological complications and may hasten them. With advances in HCT and in our ability to care for patients with IBMFS, an increasing number of survivors are making it imperative to not only diagnose but also treat late effects from the pre-, peri-, and post-HCT course and complications relating to the natural history of the syndrome. As the field of HCT evolves to allow for the incorporation of alternate graft sources, for expansion of donor options to include unrelated and mismatched donors, and for use of reduced-intensity conditioning or reduced toxicity myeloablative regimens, we have yet to determine if these advances modify the disease-specific course. While long-term outcomes of these patients are often included under one umbrella, this article seeks to address disease-specific post-HCT outcomes within IBMFS.

Minimal intensity conditioning strategies for bone marrow failure: is it time for "preventative" transplants?

Hematopoietic cell transplantation (HCT) can cure blood dyscrasias and reduce the risk of hematologic cancers in patients with inherited bone marrow failure syndromes (IBMFS). However, because of its high mortality rate, HCT is generally reserved until patients with IBMFS manifest life-threatening cytopenias or myeloid malignancy, at which point outcomes are poor. Screening tests that accurately predict transformation and enable timely intervention are lacking. These unknowns and risks limit the use of HCT in patients with IBMFS, sometimes until significant disease-related sequelae have occurred. A major goal for IBMFS is to reduce cellular therapy-related complications to the point that earlier intervention can be considered before significant transfusion exposure, occurrence of comorbidities, or malignant transformation. In recent decades, disease-specific allogeneic HCT trials have yielded significant improvements in outcomes in IBMFS conditions, including Fanconi anemia and dyskeratosis congenita. This is in large part due to marked reductions in conditioning intensity to address the increased sensitivity of these patients to cytotoxic chemotherapy and radiation. The success of these approaches may also indicate an ability to leverage intrinsic fitness defects of hematopoietic stem and progenitor cells across IBMFS disorders. Now with advances in tracking somatic genetic evolution in hematopoiesis and tailored minimal intensity conditioning regimens, this question arises: is it time for preventative HCT for IBMFS?

Germline predisposition traits in allogeneic hematopoietic stem-cell transplantation for myelodysplastic syndromes: a survey-based study and position paper on behalf of the Chronic Malignancies Working Party of the EBMT

The recent application of whole exome or whole genome sequencing unveiled a plethora of germline variants predisposing to myeloid disorders, particularly myelodysplastic neoplasms. The presence of such variants in patients with myelodysplastic syndromes has important clinical repercussions for haematopoietic stem-cell transplantation, from donor selection and conditioning regimen to graft-versus-host disease prophylaxis and genetic counselling for relatives. No international guidelines exist to harmonise management approaches to this particular clinical scenario. Moreover, the application of germline testing, and how this informs clinical decisions, differs according to the expertise of individual clinical practices and according to different countries, health-care systems, and legislations. Leveraging the global span of the European Society for Blood and Marrow Transplantation (EBMT) network, we took a snapshot of the current European situation on these matters by disseminating an electronic survey to EBMT centres experienced in myelodysplastic syndromes transplantation. An international group of haematologists, transplantation physicians, paediatricians, nurses, and experts in molecular biology and constitutional genetics with experience in myelodysplastic syndromes contributed to this Position Paper. The panel met during multiple online meetings to discuss the results of the EBMT survey and to establish suggested harmonised guidelines for such clinical situations, which are presented here.

Pediatric Bone Marrow Failure: A Broad Landscape in Need of Personalized Management

Irreversible severe bone marrow failure (BMF) is a life-threatening condition in pediatric patients. Most important causes are inherited bone marrow failure syndromes (IBMFSs) and (pre)malignant diseases, such as myelodysplastic syndrome (MDS) and (idiopathic) aplastic anemia (AA). Timely treatment is essential to prevent infections and bleeding complications and increase overall survival (OS). Allogeneic hematopoietic stem cell transplantation (HSCT) provides a cure for most types of BMF but cannot restore non-hematological defects. When using a matched sibling donor (MSD) or a matched unrelated donor (MUD), the OS after HSCT ranges between 60 and 90%. Due to the introduction of post-transplantation cyclophosphamide (PT-Cy) to prevent graft versus host disease (GVHD), alternative donor HSCT can reach similar survival rates. Although HSCT can restore ineffective hematopoiesis, it is not always used as a first-line therapy due to the severe risks associated with HSCT. Therefore, depending on the underlying cause, other treatment options might be preferred. Finally, for IBMFSs with an identified genetic etiology, gene therapy might provide a novel treatment strategy as it could bypass certain limitations of HSCT. However, gene therapy for most IBMFSs is still in its infancy. This review summarizes current clinical practices for pediatric BMF, including HSCT as well as other disease-specific treatment options.

Human leucocyte antigen-matched related haematopoietic stem cell transplantation using low-dose cyclophosphamide, fludarabine and thymoglobulin in children with severe aplastic anaemia

When human leucocyte antigen-matched related donors are available, haematopoietic stem cell transplantation (HSCT) in children with severe aplastic anaemia (SAA) represents the standard of care. Cyclophosphamide (Cy) 200 mg/kg and anti-thymocyte globulin (ATG) are frequently administered, but to-date, no standard conditioning regimen exists. In this study, we investigated the efficacy of a unified HSCT conditioning protocol consisting of low-dose Cy 80 mg/kg, fludarabine and ATG. Data were reviewed from children aged ≤14 years with either acquired SAA or non-Fanconi anaemia inherited bone marrow failure syndrome (IBMFS) between 2011 and 2022 at various Saudi institutions. Graft-versus-host disease (GVHD) prophylaxis included mycophenolate mofetil and calcineurin inhibitors. HSCT was performed in 32 children (17 females and 15 males). Nine patients had deleterious mutations (two ERCC6L2, two ANKRD26, two TINF2, one LZTFL1, one RTEL1 and one DNAJC21). Four patients had short telomeres. All 32 patients engrafted successfully. At 3 years post-transplant, the event-free survival was 93% and overall survival was 95%. Two patients experienced secondary graft failure or myelodysplastic syndrome. A low probability of GVHD was observed (one acute GVHD II and one mild chronic GVHD). These data highlight how HSCT using low-dose Cy as part of a fludarabine-based regimen is safe and effective in SAA/non-Fanconi anaemia IBMFS.

Molecular etiology of defective nuclear and mitochondrial ribosome biogenesis: Clinical phenotypes and therapy

Ribosomopathies are rare congenital disorders associated with defective ribosome biogenesis due to pathogenic variations in genes that encode proteins related to ribosome function and biogenesis. Defects in ribosome biogenesis result in a nucleolar stress response involving the TP53 tumor suppressor protein and impaired protein synthesis leading to a deregulated translational output. Despite the accepted notion that ribosomes are omnipresent and essential for all cells, most ribosomopathies show tissue-specific phenotypes affecting blood cells, hair, spleen, or skin. On the other hand, defects in mitochondrial ribosome biogenesis are associated with a range of clinical manifestations affecting more than one organ. Intriguingly, the deregulated ribosomal function is also a feature in several human malignancies with a selective upregulation or downregulation of specific ribosome components. Here, we highlight the clinical conditions associated with defective ribosome biogenesis in the nucleus and mitochondria with a description of the affected genes and the implicated pathways, along with a note on the treatment strategies currently available for these disorders.

Late Presentation of Dyskeratosis Congenita: Germline Predisposition to Adult-Onset Secondary Acute Myeloid Leukemia

Classic dyskeratosis congenita is a hereditary disease where the majority of patients present with bone marrow failure and mucocutaneous changes: mainly skin pigmentation, nail dystrophy, oral premalignant leukoplakia, in addition to increased risk for malignancies. A 63-year-old man with a long history of untreated chronic pulmonary disease, a smoker in the past, presented initially with pancytopenia and a clinical diagnosis of myelodysplastic syndrome with excess blasts returned a month later with leukocytosis (WBC 215.9 × 10⁶/μL) and diagnosed with acute myeloid leukemia (AML) with deletion of chromosome 7 and FLT3-TKD mutation. The patient's mother and sister died in their 6th decade from rapidly progressing fulminant pulmonary fibrosis. He had abnormal skin pigmentation and oral leukoplakia on presentation. He was induced with 7 + 3 chemotherapy and started on midostaurin but experienced prolonged cytopenias, complicated by hypoxic acute on chronic respiratory failure requiring intubation and mechanical ventilation. D + 28 and D + 36 bone marrow examination showed trilineage hypoplasia but no blasts, though the D + 28 bone marrow biopsy revealed one metaphase with del (7) that was cleared on D + 35. The constellation of clinical features and strong family history along with del 7 and FLT3-TKD AML with preceding MDS highly suggests a germline predisposition state dyskeratosis congenita. Germline predispositions are often underrecognized as delayed onset conditions leading to AML and may have treatment and preventative implications especially genetic counseling for blood-related family members.

Telomere biology disorders: time for moving towards the clinic?

Telomere biology disorders (TBDs) are a group of rare diseases caused by mutations that impair telomere maintenance. Mutations that cause reduced levels of TERC/hTR, the telomerase RNA component, are found in most TBD patients and include loss-of-function mutations in hTR itself, in hTR-binding proteins [NOP10, NHP2, NAF1, ZCCHC8, and dyskerin (DKC1)], and in proteins required for hTR processing (PARN). These patients show diverse clinical presentations that most commonly include bone marrow failure (BMF)/aplastic anemia (AA), pulmonary fibrosis, and liver cirrhosis. There are no curative therapies for TBD patients. An understanding of hTR biogenesis, maturation, and degradation has identified pathways and pharmacological agents targeting the poly(A) polymerase PAPD5, which adds 3'-oligoadenosine tails to hTR to promote hTR degradation, and TGS1, which modifies the 5'-cap structure of hTR to enhance degradation, as possible therapeutic approaches. Critical next steps will be clinical trials to establish the effectiveness and potential side effects of these compounds in TBD patients.

Recent advances in hematopoietic cell transplantation for inherited bone marrow failure syndromes

Inherited bone marrow failure syndromes (IBMFSs) are a group of rare genetic disorders characterized by bone marrow failure with unique phenotypes and predisposition to cancer. Classical IBMFSs primarily include Fanconi anemia with impaired DNA damage repair, dyskeratosis congenita with telomere maintenance dysfunction, and Diamond-Blackfan anemia with aberrant ribosomal protein biosynthesis. Recently, comprehensive genetic analyses have been implemented for the definitive diagnosis of classic IBMFSs, and advances in molecular genetics have led to the identification of novel disorders such as AMeD and MIRAGE syndromes. Allogeneic hematopoietic cell transplantation (HCT), a promising option to overcome impaired hematopoiesis in patients with IBMFSs, does not correct nonhematological defects and may enhance the risk of secondary malignancies. Disease-specific management is necessary because IBMFSs differ in underlying defects and are associated with varying degrees of risk for clonal evolution and early or late complications after HCT. In addition, long-term follow-up is essential to detect complications related to the IBMFS or HCT. This review provides a summary of current clinical practices along with the latest data on HCT in IBMFSs.

Reduced-intensity conditioning-based hematopoietic cell transplantation for dyskeratosis congenita: Single-center experience and literature review

BACKGROUND

Bone marrow failure in dyskeratosis congenita (DKC) is progressive, and allogeneic hematopoietic cell transplantation (HCT) is the only curative treatment. However, outcomes after HCT are suboptimal because of mucosal, vascular, pulmonary, and hepatic fragility, which can be exacerbated by chemotherapy conditioning and graft-versus-host disease (GVHD). These toxicities can be mitigated by reducing the intensity of the conditioning regimen.

PROCEDURES

We performed a retrospective analysis on pediatric patients with DKC who underwent HCT at our institution between 2008 and 2019.

RESULTS

We identified nine patients (median age, 5.7 years) who underwent HCT with a fludarabine-based reduced-intensity conditioning (RIC) regimen. GVHD prophylaxis consisted of tacrolimus plus mycophenolate mofetil (MMF) (n  =  8), tacrolimus/pentostatin (n  =  1), or cyclosporine/MMF (n  =  1). The median time to neutrophil engraftment was 19 days (range, 13-26 days), and the median time to platelet engraftment was 18 days (range, 17-43 days). Lung function, as measured by spirometry in six patients, remained stable during post-HCT observation. Six patients (67%) remain alive, with a median follow-up of 73.5 months.

CONCLUSION

Because of toxicity after myeloablative conditioning, RIC is becoming standard for HCT in DKC. These results suggest that RIC regimen is feasible and safe for patients with DKC and does not accelerate pulmonary damage in the short-to-medium term after HCT.

The clinical and functional effects of TERT variants in myelodysplastic syndrome

Germline pathogenic TERT variants are associated with short telomeres and an increased risk of developing myelodysplastic syndrome (MDS) among patients with a telomere biology disorder. We identified TERT rare variants in 41 of 1514 MDS patients (2.7%) without a clinical diagnosis of a telomere biology disorder who underwent allogeneic transplantation. Patients with a TERT rare variant had shorter telomere length (P < .001) and younger age at MDS diagnosis (52 vs 59 years, P = .03) than patients without a TERT rare variant. In multivariable models, TERT rare variants were associated with inferior overall survival (P = .034) driven by an increased incidence of nonrelapse mortality (NRM; P = .015). Death from a noninfectious pulmonary cause was more frequent among patients with a TERT rare variant. Most variants were missense substitutions and classified as variants of unknown significance. Therefore, we cloned all rare missense variants and quantified their impact on telomere elongation in a cell-based assay. We found that 90% of TERT rare variants had severe or intermediate impairment in their capacity to elongate telomeres. Using a homology model of human TERT bound to the shelterin protein TPP1, we inferred that TERT rare variants disrupt domain-specific functions, including catalysis, protein-RNA interactions, and recruitment to telomeres. Our results indicate that the contribution of TERT rare variants to MDS pathogenesis and NRM risk is underrecognized. Routine screening for TERT rare variants in MDS patients regardless of age or clinical suspicion may identify clinically inapparent telomere biology disorders and improve transplant outcomes through risk-adapted approaches.

Hematopoietic stem cell transplantation for classical inherited bone marrow failure syndromes: an update

INTRODUCTION

Inherited bone marrow failure syndromes (IBMFS) feature complex molecular pathophysiology resulting in ineffective hematopoiesis and increased risk of progression to myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Allogenic hematopoietic stem cell transplantation (HSCT) is the only well-established cure for the hematological manifestations of these diseases.

AREAS COVERED

In recent years, analysis of large series from international databases (mainly from the European Bone Marrow Transplantation [EBMT] database) has improved knowledge about HSCT in IBMFS. This review, following a thorough Medline search of the pertinent published studies, reports the most recent data on HSCT in IBMFS.

EXPERT OPINION

Despite the common features, IBMFS are very different in their manifestations and in the occurrence and management of HSCT complications. Thus, a 'disease-specific' HSCT using an optimized conditioning regimen based on the characteristics of the disease is essential for achieving long-term survival. The phenotypical heterogeneity associated with extramedullary abnormalities has to be carefully evaluated before HSCT because transplantation may only correct impaired hematopoiesis. HSCT may be associated with the risk of treatment-related mortality and with significant early and late morbidity. For these reasons, the benefits should be carefully weighed against the risks.

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.

Telomere biology disorder prevalence and phenotypes in adults with familial hematologic and/or pulmonary presentations

Telomere biology disorders (TBDs) present heterogeneously, ranging from infantile bone marrow failure associated with very short telomeres to adult-onset interstitial lung disease (ILD) with normal telomere length. Yield of genetic testing and phenotypic spectra for TBDs caused by the expanding list of telomere genes in adults remain understudied. Thus, we screened adults aged ≥18 years with a personal and/or family history clustering hematologic disorders and/or ILD enrolled on The University of Chicago Inherited Hematologic Disorders Registry for causative variants in 13 TBD genes. Sixteen (10%) of 153 probands carried causative variants distributed among TERT (n = 6), TERC (n = 4), PARN (n = 5), or RTEL1 (n = 1), of which 19% were copy number variants. The highest yield (9 of 22 [41%]) was in families with mixed hematologic and ILD presentations, suggesting that ILD in hematology populations and hematologic abnormalities in ILD populations warrant TBD genetic testing. Four (3%) of 117 familial hematologic disorder families without ILD carried TBD variants, making TBD second to only DDX41 in frequency for genetic diagnoses in this population. Phenotypes of 17 carriers with heterozygous PARN variants included 4 (24%) with hematologic abnormalities, 67% with lymphocyte telomere lengths measured by flow cytometry and fluorescence in situ hybridization at or above the 10th percentile, and a high penetrance for ILD. Alternative etiologies for cytopenias and/or ILD such as autoimmune features were noted in multiple TBD families, emphasizing the need to maintain clinical suspicion for a TBD despite the presence of alternative explanations.

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.

Generation of dyskeratosis congenita-like hematopoietic stem cells through the stable inhibition of DKC1

Dyskeratosis congenita (DC) is a rare telomere biology disorder, which results in different clinical manifestations, including severe bone marrow failure. To date, the only curative treatment for the bone marrow failure in DC patients is allogeneic hematopoietic stem cell transplantation. However, due to the toxicity associated to this treatment, improved therapies are recommended for DC patients. Here, we aimed at generating DC-like human hematopoietic stem cells in which the efficacy of innovative therapies could be investigated. Because X-linked DC is the most frequent form of the disease and is associated with an impaired expression of DKC1, we have generated DC-like hematopoietic stem cells based on the stable knock-down of DKC1 in human CD34⁺ cells with lentiviral vectors encoding for DKC1 short hairpin RNAs. At a molecular level, DKC1-interfered CD34⁺ cells showed a decreased expression of TERC, as well as a diminished telomerase activity and increased DNA damage, cell senescence, and apoptosis. Moreover, DKC1-interfered human CD34⁺ cells showed defective clonogenic ability and were incapable of repopulating the hematopoiesis of immunodeficient NSG mice. The development of DC-like hematopoietic stem cells will facilitate the understanding of the molecular and cellular basis of this inherited bone marrow failure syndrome and will serve as a platform to evaluate the efficacy of new hematopoietic therapies for DC.

Short telomere length predicts nonrelapse mortality after stem cell transplantation for myelodysplastic syndrome

Allogeneic hematopoietic stem cell transplantation is the only potentially curative treatment for patients with myelodysplastic syndrome (MDS), but long-term survival is limited by the risk of transplant-related complications. Short telomere length, mediated by inherited or acquired factors, impairs cellular response to genotoxic and replicative stress and could identify patients at higher risk for toxicity after transplantation. We measured relative telomere length in pretransplant recipient blood samples in 1514 MDS patients and evaluated the association of telomere length with MDS disease characteristics and transplantation outcomes. Shorter telomere length was significantly associated with older age, male sex, somatic mutations that impair the DNA damage response, and more severe pretransplant cytopenias, but not with bone marrow blast count, MDS treatment history, or history of prior cancer therapy. Among 1267 patients ≥40 years old, telomere length in the shortest quartile was associated with inferior survival (P < .001) because of a high risk of nonrelapse mortality (NRM; P = .001) after adjusting for significant clinical and genetic variables. The adverse impact of shorter telomeres on NRM was independent of recipient comorbidities and was observed selectively among patients receiving more intensive conditioning, including myeloablative regimens and higher dose melphalan-based reduced-intensity regimens. The effect of shorter telomeres on NRM was prominent among patients who developed severe acute graft-versus-host disease, suggesting that short telomere length may limit regenerative potential of mucosal tissues after acute injury. MDS patients with shorter telomere length, who have inferior survival driven by excess toxicity, could be considered for strategies focused on minimizing toxic effects of transplantation.

Genetic Predisposition to Myelodysplastic Syndrome in Clinical Practice

Myelodysplastic syndromes (MDSs) are a heterogeneous group of marrow failure disorders that primarily affect older persons but also occur at a lower frequency in children and young adults. There is increasing recognition of an inherited predisposition to MDS as well as other myeloid malignancies for patients of all ages. Germline predisposition to MDS can occur as part of a syndrome or sporadic disease. The timely diagnosis of an underlying genetic predisposition in the setting of MDS is important. This article delineates germline genetic causes of MDS and provides a scaffold for the diagnosis and management of patients in this context.

Monitoring and treatment of MDS in genetically susceptible persons

Genetic susceptibility to myelodysplastic syndrome (MDS) occurs in children with inherited bone marrow failure syndromes, including Fanconi anemia, Shwachman Diamond syndrome, and dyskeratosis congenita. Available evidence (although not perfect) supports annual surveillance of the blood count and bone marrow in affected persons. Optimal treatment of MDS in these persons is most commonly transplantation. Careful consideration must be given to host susceptibility to DNA damage when selecting a transplant strategy, because significant dose reductions and avoidance of radiation are necessary. Transplantation before evolution to acute myeloid leukemia (AML) is optimal, because outcomes of AML are extremely poor. Children and adults can present with germline mutations in GATA2 and RUNX1, both of which are associated with a 30% to 40% chance of evolution to MDS. GATA2 deficiency may be associated with a clinically important degree of immune suppression, which can cause severe infections that can complicate transplant strategies. GATA2 and RUNX1 deficiency is not associated with host susceptibility to DNA damage, and therefore, conventional treatment strategies for MDS and AML can be used. RUNX1 deficiency has a highly variable phenotype, and MDS can occur in childhood and later in adulthood within the same families, making annual surveillance with marrow examination burdensome; however, such strategies should be discussed with affected persons, allowing an informed choice.

Genetic predisposition to MDS: diagnosis and management

Myelodysplastic syndromes (MDS) are a heterogeneous group of disorders characterized by clonal hematopoiesis with a propensity to evolve into acute myeloid leukemia. MDS presenting in children and young adults is associated with features clinically and biologically distinct from MDS arising in older adults. MDS presenting in children and young adults is associated with a higher likelihood of an underlying genetic predisposition; however, genetic predisposition is increasingly recognized in a subset of older adults. The diagnosis of a genetic predisposition to MDS informs clinical care and treatment selection. Early diagnosis allows a tailored approach to management and surveillance. Genetic testing now offers a powerful diagnostic approach but also poses new challenges and caveats. Clinical expertise in these disorders together with scientific expertise regarding the affected genes is essential for diagnosis. Understanding the basic mechanisms of genetic predisposition to myeloid malignancies may inform surveillance strategies and lead to novel therapies. The cases presented in this article illustrate challenges to the diagnosis of germline genetic predisposition to MDS and how the diagnosis affects clinical management and treatment.

Cord blood transplantation for bone marrow failure syndromes: state of art

Hematopoietic stem cell transplantation (HSCT) and immunosuppressive therapy (IST) represent the milestones of the treatment algorithm for idiopathic and inherited bone marrow failure (BMF) disorders. However, patients lacking a suitable donor or failing IST still have a poor prognosis. Cord blood transplantation (CBT) has extended the possibility of HSCT for many patients in case of the absence of an eligible donor, and although in the last years, this procedure is less used in several hematological diseases, it remains an option for the treatment of patients with BMF syndromes. Nevertheless, optimization of conditioning regimen and cord blood unit selection is warranted to reduce the risk of graft failure and transplant-related mortality. This review summarizes the state of art of CBT in the field of BMF diseases, focusing on historical and recent issues in idiopathic aplastic anemia and inherited disorders.

Prognostic significance of pulmonary function tests in dyskeratosis congenita, a telomere biology disorder

Pulmonary fibrosis and pulmonary arteriovenous malformations are known manifestations of dyskeratosis congenita (DC), a telomere biology disorder (TBD) and inherited bone marrow failure syndrome caused by germline mutations in telomere maintenance genes resulting in very short telomeres. Baseline pulmonary function tests (PFTs) and long-term clinical outcomes have not been thoroughly studied in DC/TBDs.

In this retrospective study, 43 patients with DC and 67 unaffected relatives underwent baseline PFTs and were followed for a median of 8 years (range 1–14). Logistic regression and competing risk models were used to compare PFT results in relation to clinical and genetic characteristics, and patient outcomes.

Restrictive abnormalities on spirometry and moderate-to-severe reduction in diffusing capacity of the lung for carbon monoxide were significantly more frequent in patients with DC than relatives (42% versus 12%; p=0.008). The cumulative incidence of pulmonary disease by age 20 years was 55% in patients with DC with baseline PFT abnormalities compared with 17% in those with normal PFTs (p=0.02). None of the relatives developed pulmonary disease. X-linked recessive, autosomal recessive inheritance or heterozygous TINF2 variants were associated with early-onset pulmonary disease that mainly developed after haematopoietic cell transplantation (HCT). Overall, seven of 14 patients developed pulmonary disease post-HCT at a median of 4.7 years (range 0.7–12). The cumulative incidence of pulmonary fibrosis in patients with heterozygous non-TINF2 pathogenic variants was 70% by age 60 years.

Baseline PFT abnormalities are common in patients with DC and associated with progression to significant pulmonary disease. Prospective studies are warranted to facilitate clinical trial development for patients with DC and related TBDs.

About 40% of patients with dyskeratosis congenita, a telomere biology disorder, have abnormal pulmonary function tests and progress to life-threatening pulmonary disease (PD). Prospective therapeutic studies of PD in these disorders are urgently needed.http://bit.ly/2HBSNCO

An update on the biology and management of dyskeratosis congenita and related telomere biology disorders

Introduction: Telomere biology disorders (TBDs) encompass a group of illnesses caused by germline mutations in genes regulating telomere maintenance, resulting in very short telomeres. Possible TBD manifestations range from complex multisystem disorders with onset in childhood such as dyskeratosis congenita (DC), Hoyeraal-Hreidarsson syndrome, Revesz syndrome and Coats plus to adults presenting with one or two DC-related features.Areas covered: The discovery of multiple genetic causes and inheritance patterns has led to the recognition of a spectrum of clinical features affecting multiple organ systems. Patients with DC and associated TBDs are at high risk of bone marrow failure, cancer, liver and pulmonary disease. Recently, vascular diseases, including pulmonary arteriovenous malformations and gastrointestinal telangiectasias, have been recognized as additional manifestations. Diagnostics include detection of very short leukocyte telomeres and germline genetic testing. Hematopoietic cell transplantation and lung transplantation are the only current therapeutic modalities but are complicated by numerous comorbidities. This review summarizes the pathophysiology underlying TBDs, associated clinical features, management recommendations and therapeutic options.Expert opinion: Understanding TBDs as complex, multisystem disorders with a heterogenous genetic background and diverse phenotypes, highlights the importance of clinical surveillance and the urgent need to develop new therapeutic strategies to improve health outcomes.

Pre-transplant short telomeres are associated with high mortality risk after unrelated donor haematopoietic cell transplant for severe aplastic anaemia

Telomeres are essential for chromosomal stability and markers of biological age. We evaluated the effect of pre-transplant short (<10th percentile-for-age) or very short (<5th or <1st percentile-for-age) leucocyte telomere length on survival after unrelated donor haematopoietic cell transplantation (HCT) for acquired severe aplastic anaemia (SAA). Patient pre-transplant blood samples and clinical data were available at the Center for International Blood and Marrow Transplant Research. We used quantitative real time polymerase chain reaction to measure relative telomere length (RTL) in 490 SAA patients who received HCT between 1990 and 2013 (median age = 20 years). One hundred and twelve patients (22·86%) had pre-HCT RTL <10th percentile-for-age, with the majority below the 5th percentile (N = 80, 71·43%). RTL <10th percentile-for-age was associated with a higher risk of post-HCT mortality (hazard ratio [HR] = 1·78, 95% confidence interval [CI]=1·18-2·69, P = 0·006) compared with RTL ≥50th percentile; no survival differences were noted in longer RTL categories (P > 0·10). Time-dependent effects for post-HCT mortality were only observed in relation to very short RTL; HR comparing RTL <5th versus ≥5th percentile = 1·38, P = 0·15 for the first 12 months after HCT, and HR = 3·91, P < 0·0001, thereafter, P-heterogeneity = 0·008; the corresponding HRs for RTL <1st versus ≥1st percentile = 1·29, P = 0·41, and HR = 5·18, P < 0·0001, P-heterogeneity = 0·005. The study suggests a potential role for telomere length in risk stratification of SAA patients in regard to their HCT survival.

Advances in the gene therapy of monogenic blood cell diseases

Hematopoietic gene therapy has markedly progressed during the last 15 years both in terms of safety and efficacy. While a number of serious adverse events (SAE) were initially generated as a consequence of genotoxic insertions of gamma-retroviral vectors in the cell genome, no SAEs and excellent outcomes have been reported in patients infused with autologous hematopoietic stem cells (HSCs) transduced with self-inactivated lentiviral and gammaretroviral vectors. Advances in the field of HSC gene therapy have extended the number of monogenic diseases that can be treated with these approaches. Nowadays, evidence of clinical efficacy has been shown not only in primary immunodeficiencies, but also in other hematopoietic diseases, including beta-thalassemia and sickle cell anemia. In addition to the rapid progression of non-targeted gene therapies in the clinic, new approaches based on gene editing have been developed thanks to the discovery of designed nucleases and improved non-integrative vectors, which have markedly increased the efficacy and specificity of gene targeting to levels compatible with its clinical application. Based on advances achieved in the field of gene therapy, it can be envisaged that these therapies will soon be part of the therapeutic approaches used to treat life-threatening diseases of the hematopoietic system.

The Telomerase Complex Directly Controls Hematopoietic Stem Cell Differentiation and Senescence in an Induced Pluripotent Stem Cell Model of Telomeropathy

Telomeropathies are rare disorders associated with impaired telomere length control mechanisms that frequently result from genetic mutations in the telomerase complex. Dyskeratosis congenita is a congenital progressive telomeropathy in which mutation in the telomerase RNA component (TERC) impairs telomere maintenance leading to accelerated cellular senescence and clinical outcomes resembling premature aging. The most severe clinical feature is perturbed hematopoiesis and bone-marrow failure, but the underlying mechanisms are not fully understood. Here, we developed a model of telomerase function imbalance using shRNA to knockdown TERC expression in human induced pluripotent stem cells (iPSCs). We then promoted in vitro hematopoiesis in these cells to analyze the effects of TERC impairment. Reduced TERC expression impaired hematopoietic stem-cell (HSC) differentiation and increased the expression of cellular senescence markers and production of reactive oxygen species. Interestingly, telomere length was unaffected in shTERC knockdown iPSCs, leading to conclusion that the phenotype is controlled by non-telomeric functions of telomerase. We then assessed the effects of TERC-depletion in THP-1 myeloid cells and again observed reduced hematopoietic and myelopoietic differentiative potential. However, these cells exhibited impaired telomerase activity as verified by accelerated telomere shortening. shTERC-depleted iPSC-derived and THP-1-derived myeloid precursors had lower phagocytic capacity and increased ROS production, indicative of senescence. These findings were confirmed using a BIBR1532 TERT inhibitor, suggesting that these phenotypes are dependent on telomerase function but not directly linked to telomere length. These data provide a better understanding of the molecular processes driving the clinical signs of telomeropathies and identify novel roles of the telomerase complex other than regulating telomere length.

A DNA-Methylated Sight on Autoimmune Inflammation Network across RA, pSS, and SLE

Methylation variabilities of inflammatory cytokines play important roles in the development of systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and primary Sjögren's syndrome (pSS). With heightened focus on personalized and precise medicine, it is necessary to compare and contrast the difference and similarity of cytokine methylation status between the 3 most classic autoimmune diseases (AIDs). In this study, we integrated 5 Cytokine-Chips from genome-wide DNA methylation datasets of the 3 kind of AIDs, delta-beta value was calculated for intergroup difference, and comprehensive bioinformatics analyses of cytokine genes with aberrant methylations were performed. 125 shared differential methylation variabilities (DMVs) were identified. There were 102 shared DMVs with similar methylation status; 3 hypomethylated differential methylation regions (DMRs) across the AIDs were found, and all 3 DMRs were hypomethylated. DMRs (AZU1, LTBR, and RTEL1) were likely to serve as activator in the inflammatory process. Particularly, AZU1 and LTBR with hypomethylated TSS and first exon located in the promoter regions were able to trigger inflammation signaling cascades and play critical roles in autoimmune tautology. Moreover, functional epigenetic module (FEM) algorithm showed that different inflammatory networks are involved in different AIDs; 5 hotspots were identified as biologically plausible pathways in inducing or perpetuating of inflammation which are epigenetically deregulated in AIDs. We concluded methylation variabilities among the same cytokines can greatly impact the perpetuation of inflammatory process or signal pathway of AIDs. Differentiating the cytokine methylation status will serve as valuable resource for researchers alike to gain better understanding of the epigenetic mechanisms of the three AIDs. Even more importantly, better understanding of cytokine methylation variability existing between the three classic AIDs will aid in identification of potential epigenetic biomarkers and therapeutic targets. This trial is registered with ChiCTR-INR-16010290, a clinical trial for the treatment of rheumatoid arthritis with Warming yang and Smoothening Meridians.

Germ line predisposition to myeloid malignancies appearing in adulthood

INTRODUCTION

Germ line predisposition to myeloid neoplasms has been incorporated in the WHO 2016 classification of myeloid neoplasms and acute leukemia. The new category of disease is named hereditary myeloid disorder (HMD). Although most myeloid neoplasms are sporadic, germ line mutations and familial predisposition can contribute to development of chronic myeloid diseases and acute myeloid leukemia. This finding and upcoming frequent use of genome wide detection of molecular aberrations will lead to a higher detection rate of a genetic predisposition and influence treatment decisions. Hereditary predisposition is responsible for 5-10% of myeloid malignancies. Management of affected patients begins by the awareness of treating physicians of the problem and a precise work up of the patient and family members. Areas covered: This review focuses on current knowledge about germ line predisposition for myeloid neoplasms including diagnostic, prognostic, and therapeutic aspects in adult patients. Essential information for clinical routine is provided. Expert commentary: Compared to a patient without predisposition, adaptation of treatment strategy for patients with an HMD is often necessary, especially to avoid higher risk of relapse or higher toxicity during chemotherapy or transplantation. Mistakes in choice of a related donor can be omitted. Relatives at risk of developing a HMD need specific surveillance.

Evaluation and Management of Hematopoietic Failure in Dyskeratosis Congenita

Dyskeratosis congenita (DC) is a rare, inherited bone marrow failure (BMF) syndrome characterized by variable manifestations and ages of onset, and predisposition to cancer. DC is one of a spectrum of diseases caused by mutations in genes regulating telomere maintenance, collectively referred to as telomere biology disorders (TBDs). Hematologic disease is common in children with DC/TBD. Timely diagnosis of underlying TBD in patients with BMF affects treatment and has been facilitated by increased awareness and availability of diagnostic tests in recent years. This article summarizes the pathophysiology, evaluation, and management of hematopoietic failure in patients with DC and other TBDs.

Inherited bone marrow failure syndromes: considerations pre- and posttransplant

Patients with inherited bone marrow failure syndromes are usually identified when they develop hematologic complications such as severe bone marrow failure, myelodysplastic syndrome, or acute myeloid leukemia. They often have specific birth defects or other physical abnormalities that suggest a syndrome, and sequencing of specific genes or next-generation sequencing can determine or confirm the particular syndrome. The 4 most frequent syndromes are Fanconi anemia, dyskeratosis congenita, Diamond Blackfan anemia, and Shwachman Diamond syndrome. This review discusses the major complications that develop as the patients with these syndromes age, as well as additional late effects following hematopoietic stem cell transplantation. The most common complications are iron overload in transfused patients and syndrome-specific malignancies in untransplanted patients, which may occur earlier and with higher risks in those who have received transplants.

Inherited bone marrow failure syndromes: considerations pre- and posttransplant

Patients with inherited bone marrow failure syndromes are usually identified when they develop hematologic complications such as severe bone marrow failure, myelodysplastic syndrome, or acute myeloid leukemia. They often have specific birth defects or other physical abnormalities that suggest a syndrome, and sequencing of specific genes or next-generation sequencing can determine or confirm the particular syndrome. The 4 most frequent syndromes are Fanconi anemia, dyskeratosis congenita, Diamond Blackfan anemia, and Shwachman Diamond syndrome. This review discusses the major complications that develop as the patients with these syndromes age, as well as additional late effects following hematopoietic stem cell transplantation. The most common complications are iron overload in transfused patients and syndrome-specific malignancies in untransplanted patients, which may occur earlier and with higher risks in those who have received transplants.

Allogeneic hematopoietic stem cell transplantation for dyskeratosis congenita

PURPOSE OF REVIEW

Dyskeratosis congenita is an inherited bone marrow failure syndrome caused by defects in telomere maintenance. Hematopoietic stem cell transplantation (HSCT) is the only curative treatment for bone marrow failure because of dyskeratosis congenita. The present review summarizes the literature with respect to the diagnosis and treatment of patients with dyskeratosis congenita who received HSCT, and discusses the recent progress in the management of dyskeratosis congenita.

RECENT FINDINGS

The recent systematic review of the literature showed poor long-term outcome, with 10-year survival estimates of only 23% in 109 patients with dyskeratosis congenita who received HSCT. Multivariate analysis identified age greater than 20 years at HSCT, HSCT before 2000, and alternative donor source to be poor prognostic markers. HSCT for dyskeratosis congenita is characterized by a marked decline in long-term survival because of late deaths from pulmonary complications. However, a prospective study using danazol showed promising results in gain in telomere length and hematologic responses.

SUMMARY

A recent prospective study may support the recommendation that HSCT is not indicated for patients with dyskeratosis congenita; instead, they should receive androgen, particularly danazol, as a first-line therapy. Another option may be routine use of androgen after HSCT for the prophylaxis of pulmonary fibrosis.

Allogeneic Hematopoietic Cell Transplantation for Dyskeratosis Congenita: A Report of 3 Cases

Although bone marrow failure in patients with dyskeratosis congenita (DKC) can be successfully treated with allogeneic hematopoietic cell transplantation (allo-HCT) using a reduced intensity conditioning (RIC) regimen, the outcome of nonhematological disorders in patients with DKC treated with allo-HCT using RIC has not been fully elucidated. Here, we describe the clinical course of nonhematological disorders after allo-HCT with RIC in 3 consecutive patients with DKC. Allo-HCT with RIC was feasible in all cases; however, patient 1 developed lethal pulmonary disease and patient 2 experienced progression of hepatic fibrosis. Careful follow-up of patient-specific complications is required after allo-HCT in patients with DKC.

Inherited Bone Failure Syndromes, Focus on the Haematological Manifestations: A Review

The purpose of this review is to provide the haematologist with a working knowledge of the common inherited bone marrow failure syndromes (iBMFS) diagnosed in early childhood to young adulthood. Although these disorders are heterogeneous, this article discusses their common features, pathophysiology, and management. Each of these syndromes has a spectrum of clinical variation and can cause both haematological and non-haematological manifestations. Most pathogenic mutations responsible are in genes important to a progenitor cell’s ability to maintain genomic integrity, which accounts for the clinical phenotypes often affecting multiple tissues. Furthermore, all of these syndromes predispose not only to aplastic anaemia but also to myelodysplastic syndrome/acute myeloid leukaemia. Since iBMFS only account for a small percentage of childhood leukaemia cases, it is important that the clinician maintains a high clinical suspicion as appropriate diagnosis impacts treatment, health screening, and family members. Identification of iBMFS is critically important for appropriate donor selection and transplant regimens, as haematopoietic stem cell transplantation is curative for the haematological manifestations of these diseases, but treatment-related mortality can be excessive if modifications are not made to conditioning.

Late Effects Screening Guidelines after Hematopoietic Cell Transplantation for Inherited Bone Marrow Failure Syndromes: Consensus Statement From the Second Pediatric Blood and Marrow Transplant Consortium International Conference on Late Effects After Pediatric HCT

Patients with inherited bone marrow failure syndromes (IBMFS), such as Fanconi anemia (FA), dyskeratosis congenita (DC), or Diamond Blackfan anemia (DBA), can have hematologic manifestations cured through hematopoietic cell transplantation (HCT). Subsequent late effects seen in these patients arise from a combination of the underlying disease, the pre-HCT therapy, and the HCT process. During the international consensus conference sponsored by the Pediatric Blood and Marrow Transplant Consortium on late effects screening and recommendations following allogeneic hematopoietic cell transplantation for immune deficiency and nonmalignant hematologic diseases held in Minneapolis, Minnesota in May 2016, a half-day session was focused specifically on the unmet needs for these patients with IBMFS. This multidisciplinary group of experts in rare diseases and transplantation late effects has already published on the state of the science in this area, along with discussion of an agenda for future research. This companion article outlines consensus disease-specific long-term follow-up screening guidelines for patients with IMBFS.

Classical inherited bone marrow failure syndromes with high risk for myelodysplastic syndrome and acute myelogenous leukemia

The inherited marrow failure syndromes (IBMFS) are a heterogeneous group of diseases characterized by failure in the production of one or more blood lineage. The clinical manifestations of the IBMFS vary according to the type and number of blood cell lines involved, including different combinations of anemia, leukopenia, and thrombocytopenia. In some IBMFS, systemic non-hematologic manifestations, including congenital malformations, mucocutaneous abnormalities, developmental delay, and other medical complications, may be present. Fanconi anemia (FA), caused by germline pathogenic variants in the DNA repair genes comprising the FA/BRCA pathway is associated with congenital anomalies, bone marrow failure, and increased risk of myelodysplastic syndrome (MDS), acute myelogenous leukemia (AML), and solid tumors. Dyskeratosis congenita (DC) is a telomere biology disorder (TBD) caused by aberrations in key telomere biology genes. In addition to mucocutaneous manifestations, patients with DC are at increased risk of marrow failure, MDS, AML, pulmonary fibrosis, and other complications. Ribosomal biology defects are the primary causes of Diamond Blackfan anemia (DBA) and Shwachman Diamond syndrome (SDS). In addition to pure red blood cell aplasia, DBA is associated with elevated risk of solid tumors, AML, and MDS. Patients with SDS have pancreatic insufficiency, neutropenia, as well as MDS and AML risks. Patients with severe congenital neutropenia (SCN), caused by pathogenic variants in genes essential in myeloid development, have profound neutropenia and high risk of MDS and AML. Herein we review the genetic causes, clinical features, diagnostic modalities, predisposition to malignancies with focus on leukemogenic markers whenever available, and approaches to treatments of the classical IBMFS: FA, DC, SDS, DBA, and SCN.

[Recurrent pulmonary infection and oral mucosal ulcer]

An 8-year-old girl who had experienced intermittent cough and fever over a 3 year period, was admitted after experiencing a recurrence for one month. One year ago the patient experienced a recurrent oral mucosal ulcer. Physical examination showed vitiligo in the skin of the upper right back. Routine blood tests and immune function tests performed in other hospitals had shown normal results. Multiple lung CT scans showed pulmonary infection. The patient had recurrent fever and cough and persistent presence of some lesions after anti-infective therapy. The antitubercular therapy was ineffective. Routine blood tests after admission showed agranulocytosis. Gene detection was performed and she was diagnosed with dyskeratosis congenita caused by homozygous mutation in RTEL1. Patients with dyskeratosis congenita with RTEL1 gene mutation tend to develop pulmonary complications. Since RTEL1 gene sequence is highly variable with many mutation sites and patterns and can be inherited via autosomal dominant or recessive inheritance, this disease often has various clinical manifestations, which may lead to missed diagnosis or misdiagnosis. For children with unexplained recurrent pulmonary infection, examinations of the oral cavity, skin, and nails and toes should be taken and routine blood tests should be performed to exclude dyskeratosis congenita. There are no specific therapies for dyskeratosis congenita at present, and when bone marrow failure and pulmonary failure occur, hematopoietic stem cell transplantation and lung transplantation are the only therapies. Androgen and its derivatives are effective in some patients. Drugs targeting the telomere may be promising for patients with dyskeratosis congenita.

Current Knowledge and Priorities for Future Research in Late Effects after Hematopoietic Cell Transplantation for Inherited Bone Marrow Failure Syndromes: Consensus Statement from the Second Pediatric Blood and Marrow Transplant Consortium International Conference on Late Effects after Pediatric Hematopoietic Cell Transplantation

Fanconi anemia (FA), dyskeratosis congenita (DC), and Diamond Blackfan anemia (DBA) are 3 of the most common inherited bone marrow failure syndromes (IBMFS), in which the hematologic manifestations can be cured with hematopoietic cell transplantation (HCT). Later in life, these patients face a variety of medical conditions, which may be a manifestation of underlying disease or due to pre-HCT therapy, the HCT, or a combination of all these elements. Very limited long-term follow-up data exist in these populations, with FA the only IBMFS that has specific published data. During the international consensus conference sponsored by the Pediatric Blood and Marrow Transplant Consortium entitled "Late Effects Screening and Recommendations following Allogeneic Hematopoietic Cell Transplant (HCT) for Immune Deficiency and Nonmalignant Hematologic Disease" held in Minneapolis, Minnesota in May of 2016, a half-day session was focused specifically on the unmet needs for these patients with IBMFS. A multidisciplinary group of experts discussed what is currently known, outlined an agenda for future research, and laid out long-term follow-up guidelines based on a combination of evidence in the literature as well as expert opinion. This article addresses the state of science in that area as well as consensus regarding the agenda for future research, with specific screening guidelines to follow in the next article from this group.

Transplantation for bone marrow failure: current issues

The preferred treatment of idiopathic aplastic anemia (AA) is allogeneic hematopoietic stem cell transplantation (HSCT) from a human leukocyte antigen (HLA)-identical sibling donor. Transplantation from a well-matched unrelated donor (MUD) may be considered for patients without a sibling donor after failure of immunosuppressive therapy, as may alternative transplantation (mismatched, cord blood or haplo-identical HSCT) for patients without a MUD. HSCT may also be contemplated for congenital disorders in cases of pancytopenia or severe isolated cytopenia. Currently, HSCT aims are not only to cure patients but also to avoid long-term complications, notably chronic graft-versus-host disease (GVHD), essential for a good quality of life long term. This paper summarizes recent advances in HSCT for idiopathic and inherited AA disorders. The effect of age on current transplantation outcomes, the role of transplantation in paroxysmal nocturnal hemoglobinuria, and the prevention of GVHD are also discussed. Emerging strategies regarding the role of up-front unrelated donor and alternative donor HSCT in idiopathic AA, along with advances in the treatment of clonal evolution in Fanconi anemia, are also examined.