Inherited Marrow Failure Syndromes Research Articles

When to consider inherited marrow failure syndromes in adults.

The inherited bone marrow failure syndromes (IBMFS) are a heterogenous group of disorders caused by germline mutations in related genes and characterized by bone marrow failure (BMF), disease specific organ involvement, and, in most cases, predisposition to malignancy. Their distinction from immune marrow failure can often be challenging, particularly when presentations occur in adulthood or are atypical. A combination of functional (disease specific assays) and genetic testing is optimal in assessing all new BMF patients for an inherited etiology. However, genetic testing is costly and may not be available worldwide due to resource constraints; in such cases, clinical history, standard laboratory testing, and the use of algorithms can guide diagnosis. Interpretation of genetic results can be challenging and must reflect assessment of pathogenicity, inheritance pattern, clinical phenotype, and specimen type used. Due to the progressive use of genomics, new IBMFS continue to be identified, widening the spectrum of these disorders.

Donor Lymphocyte Cell-Specific Telomere Length and Causes of Death after Unrelated Hematopoietic Cell Transplant in Patients with Marrow Failure

Introduction. Several recent studies indicated that longer donor telomere length provides a survival advantage to patients receiving unrelated donor hematopoietic cell transplant (HCT) for severe aplastic anemia (SAA). However, the cause behind this observation is still unclear.Method. From the Center for International Blood and Marrow Transplant Research (CIBMTR®) database and biorepository, we identified 197 marrow failure patients who received unrelated donor HCT between 1988-2004, and for whom donor cryopreserved peripheral blood mononuclear cells were available. We used flow cytometry and fluorescence in situ hybridization (Flow FISH) analysis to measure telomere length in 4 lymphocyte cell subtypes: naïve enriched T-cells (CD45RA+CD20-), memory enriched T-cells (CD45RA-CD20-), NK-fully differentiated T cells (CD45RA+CD57+), and B cells (CD45RA+CD20+). We used competing risks survival regression for cause-specific death analysis. Cause of death categories used as reported to CIBMTR by the transplant centers. We focused on deaths from infections, graft- versus -host disease (G v HD), and graft failure, each modeled separately, with deaths from causes other than that of interest representing competing events. Models were adjusted for donor age, HLA matching, disease subtype, Karnofsky score, year of HCT, and prior SAA therapy. Median follow-up of the study was 60 months.Results. All patients in this study received bone marrow grafts, 32% had inherited marrow failure syndrome, and 49% received myeloablative conditioning. During follow-up, 135 died, 26% of the deaths were from infections, 18% from G v HD, 10% from primary or secondary graft failure, according to reporting from the transplant center. Longer donor telomere lengths in B cells (HR=0.63, 95% CI=0.46-0.87, p=0.006), and possibly NK- fully differentiated T cells (HR=0.7, 95% CI=0.51-0.97, p=0.03) were associated with lower risk of infection-related death. No statistically significant associations were seen with telomere length of the naïve or memory T-cells in relation to death due to infection. Donor telomere lengths in any of the tested lymphocyte subsets were not associated with death caused by G v HD or graft failure (p<0.05).Conclusions. Longer donor telomere length protects SAA patients from post-HCT infection-related deaths. Validating these results in recent and larger cohort is warranted. DisclosuresLee:Mallinckrodt: Honoraria; Kadmon: Other: One-time advisory board member; Amgen: Other: One-time advisory board member; Bristol-Myers-Squibb: Other: One-time advisory board member.

MDS and AML in Shwachman-Diamond Syndrome: Clinical Features and Outcomes

Genetic predisposition to MDS and AML is recognized in a growing subset of patients, but data to inform medical management and outcomes are sparse. Shwachman-Diamond syndrome (SDS) is an inherited marrow failure syndrome associated with increased risk of myelodysplasia (MDS) and acute myeloid leukemia (AML). The aim of this multi-institutional retrospective study was to investigate clinical features, treatment, and outcomes of 37 patients with SDS who developed MDS or AML. Diagnosis of SDS was established by SBDS genetic testing (n=30), exocrine pancreatic dysfunction (n=5), or data were unavailable (n=2). Nine individuals presented with AML (4 male, 5 female), 26 with MDS (13 male and 13 female), one male with refractory cytopenia (RC), and one male with isolated persistent somatic TP53 mutation. Eight of 26 MDS patients, had MDS-EB1 or EB2 at diagnosis, of whom two progressed to AML. Three patients initially presenting with early MDS progressed to MDS-EB1, MDS-EB2, or AML. Median age (years) at diagnosis of early MDS was 13.8 (range 0.5-28.8), for MDS-EB1/2 was 16 (range 9-30) and for AML was 33 (range 5.5-47). Nine patients with MDS and 1 patient with AML were receiving G-CSF chronically prior to diagnosis of MDS/AML.Complex cytogenetics, (>3 cytogenetic abnormalities per clone), were noted in 8/9 AML cases. One AML patient presented with normal cytogenetics. Complex clonal cytogenetic abnormalities were noted in 5 of 6 patients with MDS-EB1/EB2 for whom reports were available. Cytogenetic data were available for 16 MDS cases and clonal abnormalities were noted in 10. Aberrations involving chromosome 7 were most common. The patient with the somatic TP53 mutation had normal cytogenetics. Centralized bone marrow pathology review is currently ongoing.Follow up data were available for 8 patients with AML; 6 are deceased. Six received chemotherapy with intent to proceed to hematopoietic stem cell transplant (HSCT), of whom 5 failed to achieve remission and died with disease without proceeding to transplant. One AML patient proceeded to HSCT with progressive disease post-chemotherapy, but died with relapsed disease. One patient proceeded to HSCT without prior chemotherapy and was in remission at day 30 post-HSCT. The sole long-term surviving AML patient achieved remission with chemotherapy and underwent HSCTs with 3 separate stem cell infusions due to primary graft failure after the initial two infusions. He remains alive in remission more than 4 years after diagnosis. Notably this surviving AML patient was the only AML patient with normal cytogenetics at diagnosis.Follow up data are available for 6 of 8 patients presenting with MDS-EB1/EB2, 4 of whom are deceased. One patient who presented with MDS-EB1 is alive with relapsed disease after HSCT and one patient is in remission 100 days after HSCT.Follow up data are available for 17 of 18 early MDS patients, 7 of whom are deceased including three who had progressed to MDS-EB1, MDS-EB2, or AML. Four of the 7 deceased patients had received a HSCT. One individual with MDS died of hepatic failure unrelated to MDS. Seven MDS patients are alive in remission after HSCT without prior chemotherapy. Treatment was not reported for an additional 2 surviving patients. One patient receiving a hypomethylating agent is alive with stable disease 4.8 years from diagnosis. The patients with RC and with a TP53 clonal abnormality are alive at 6.5 years and 1.7 years from diagnosis respectively.In summary,prognosis is poor for patients with SDS who develop AML or MDS-EB1/2, with few long-term survivors due to resistant disease and treatment-related complications. Outcomes are better if transplanted for MDS prior to acquisition of increased blasts, with 10 of 17 (59%) subjects surviving (median follow up 6 years, range 1.5-11.2). AML often presents in adulthood highlighting the need for continued surveillance of SDS patients with bone marrow examinations including cytogenetics and FISH. These data demonstrate the importance of early detection of clonal evolution in this leukemia predisposition syndrome. Better markers for risk stratification are needed to identify patients who would benefit from early transplant prior to advanced clonal disease. Novel therapeutic strategies, such as targeted therapies, are urgently needed to improve outcomes of SDS patients with advanced MDS or AML. DisclosuresDiNardo:Daiichi-Sankyo: Honoraria, Research Funding; Agios: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; AbbVie: Honoraria, Research Funding. Norkin:Celgene: Honoraria, Research Funding. Shimamura:TransCellular Therapeutics: Other: Spouse is majority shareholder .

Genotypic and Phenotypic Spectrum of Dyskeratosis Congenita: Results from the Canadian Inherited Marrow Failure Registry

Introduction: Dyskeratosis congenita (DC) is an inherited bone marrow failure syndrome caused by mutations in one of 13 telomere-related genes, resulting in disruption of normal telomere maintenance; however, about 30% of patients do not have a molecular diagnosis. DC patients are at increased risk for severe bone marrow failure (SBMF), myelodysplastic syndrome (MDS), acute myeloid leukemia (AML), and solid tumours. Life expectancy is compromised by SBMF, malignancy, pulmonary and liver fibrosis, and GI bleeding. Objectives: Among patients with DC in Canada, aims were to: (1) characterize the genetic profile of DC in Canada, (2) define the spectrum of clinical features of DC, (3) determine the incidence and age when SBMF, MDS, AML or solid tumours develop, (4) identify factors that are associated with higher mortality risk, and (5) describe the causes of death. Methods: Data of patients enrolled in the Canadian Inherited Marrow Failure Registry (CIMFR) and meeting diagnostic criteria for DC between January 1, 2001 and March 1, 2018 were included. The CIMFR is a multicentre registry that captures data on patients with inherited marrow failure syndromes from pediatric tertiary referral centres across all Canadian provinces. We investigated several continuous (e.g. age at diagnosis of SBMF/MDS/AML) and categorical (e.g. mutated gene) variables that are associated with specific outcomes, namely overall survival and development of SBMF. Cox proportional hazard models were used to assess risk of death based on age at diagnosis and presence of SBMF. Kaplan-Meier curves were used to assess overall survival. Results: As of March 1st, 2018, 35 patients with DC were enrolled. The mean age of diagnosis was 10.94 years (0-39.9). The underlying genotypes were: DKC1 (7), TERT (6), TINF2 (5), RTEL1 (3), PARN (2), TERC (2) but remained undetermined in the others (10). Twenty-seven patients were classified as classical DC, 7 had Hoyeraal-Hreidarsson syndrome and 1 patient had Coats plus syndrome. Eight patients (23%) developed SBMF. The mean age of SBMF was 4.22 years (1-8.66). No statistical difference was found between genotypes and progression to SBMF (P=0.1). Modelling death as a function of time varying SBMF status using a cox proportional hazard regression model showed that the presence of SBMF in DC patients was predictive of higher mortality rate (P= 0.009, hazard ratio 5.7, CI 1.54-21.5). None of the patients developed malignancy during childhood (0-18 years). One adult patient developed skin cancer. Eleven patients (31%) received a hematopoietic stem cell transplant (HSCT). The mean age of HSCT was 9.5 years (0.5-37). Ten (29%) patients died, five of whom were recipients of HSCT. Mean age of death was 12.98 years (2-24.6). Extra-hematological complications included gastrointestinal bleeding (50%), pulmonary fibrosis (40%), overwhelming infection (40%), liver fibrosis (20%), cardiomyopathy (10%), hemolytic uremic syndrome (HUS) (10%) and thrombotic microangiopathy (TMA) (10%). Most patients had more than one organ dysfunction. Analysis of survival showed that all patients with TINF2 mutations have died (at median age of 10.8 years, range 2.5-23.25) whereas none died in the TERT group. Patients diagnosed at younger age had lower overall survival compared to patients diagnosed at older ages (P= 0.03, HR: 0.72, CI: 0.57-0.90). All deaths were due to organ dysfunction related to DC. Fifty percent of the patients had concurrent SBMF at the time of death. Conclusion: In this analysis, we characterised the genetic and phenotypic spectrum of DC patients registered in the CIMFR. We found a high mortality rate mainly related to organ dysfunction and SBMF, and described the impact of genotype, earlier age at diagnosis and presence of SBMF in predicting survival. We found that malignancy is an uncommon complication in the pediatric age group. Figure Disclosures Klaassen: Amgen Inc: Consultancy; TranQoL and KIT: Other: creater and owner of Kids ITP tool and TranQoL; Octapharma AG: Speakers Bureau; Baxalta: Speakers Bureau; Biogen Canada Limited: Speakers Bureau; Novo Nordisk Canada Inc: Consultancy; Hoffman-LaRoche Ltd: Consultancy; Agios Pharmaceuticals Inc: Consultancy; Shire Pharma Canada Inc: Consultancy. Pastore:Pfizer: Honoraria. Lipton:BMS: Consultancy, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria; Novartis: Consultancy, Research Funding; Ariad: Consultancy, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding.

Eltrombopag: Role in Cytopenias Following Hematopoietic Stem Cell Transplantation.

Eltrombopag is a small molecule oral agonist of the thrombopoietin receptor. Initially used for improving thrombocytopenia in chronic immune thrombocytopenia (ITP), it was later found to be efficacious in various other etiologies of thrombocytopenia as well as inherited marrow failure syndromes. Lately, it has been used for thrombocytopenia and poor graft function after allogeneic hematopoietic stem cell transplantation (HSCT) without any severe adverse events. Although prospective evidence of the efficacy is limited, there are increasing reports on the safety and efficacy with Eltrombopag in post HSCT thrombocytopenia and poor graft function. This provides an exciting opportunity for further research to evaluate both efficacy and cost-effectiveness of the use of Eltrombopag in this scenario. Here we review the current evidence on the indications for the use of Eltrombopag in the post allogeneic hematopoietic stem cell transplant setting.

Implementation of a screening program for identification of unrecognized inherited marrow failure syndromes.

7055 Background: Inherited marrow failure syndromes (IMFS) are considered diseases of childhood, but testing adults with atypical presentations of diseases associated with IMFS is critical for establishing an optimal treatment protocol. The most common IMFS, Fanconi Anemia and Telomere Biology Diseases, are associated with MDS and aplastic anemia (AA), head and neck cancers, skin, and cervical cancer. Such patients can have profound toxicity with standard chemotherapy regimens. Methods: We implemented a screening protocol in patients at highest risk of an undiagnosed IMFS (MDS under age 60, AA patients under age 65, and head and neck cancers under age 60) with chromosome breakage analysis and telomere length testing. Results: Our protocol diagnosed nine patients (estimated ~10% of patients &lt; age 60 with these diseases) with IMFS. The features of these patients are described in the table. Only three (33%) patients had the classic physical characteristics of IMFS. Three patients were over age 50 when diagnosed with an inherited disorder. Most importantly, in all patients the treatment approach was modified significantly, including minimizing conditioning for BMT, utilizing danazol as first line treatment for AA, as well as aggressive cancer and endocrinopathy screening. Outcomes with modified treatment have been favorable, and occult malignancies were detected through screening in two patients. Conclusions: Inherited marrow failure syndromes are uncommon yet under recognized disorders that significantly impact treatment decisions in addition to implementation of surveillance programs for both the affected individual and their relatives alike. Through this approach of thoughtful screening of patients presenting to our institution with marrow failure we identified an unrecognized IMFS in an estimated 10% of patients. [Table: see text]

Identifying Unexpected Inherited Marrow Failure Syndromes in Adults Presenting with Aplastic Anemia, MDS or Solid Tumors

The inherited marrow failure syndromes, most importantly Fanconi Anemia (FA) and the Telomere Diseases, are associated not only with marrow failure, but with endocrinopathies, pulmonary fibrosis, cirrhosis and solid organ malignancies. While these disorders classically present in childhood with physical traits and blood count abnormalities, in reality, there is a wide spectrum of clinical findings in these syndromes. Patients may present with solid organ malignancies, pulmonary or liver abnormalities, aplastic anemia (AA) or myelodysplastic syndrome (MDS). Such presentations in adults require a high index of suspicion on behalf of the clinician during the initial stages of diagnosis, as prompt recognition of an inherited marrow failure disorder is imperative to creating an optimal treatment course. Early recognition allows for institution of surveillance programs for solid tumors, routine blood and bone marrow monitoring for the development of AA or MDS, and imparts a certain prognosis. It also allows for screening of additional family members (most important siblings who may be considered as bone marrow donors) and genetic counseling for families affected by these disorders. Treatment is often directed at the underlying bone marrow failure, and as highlighted by the recently published experience at the NIH (Townsley DM et al, NEJM 2016; 374), specific drugs may impact the disease trajectory.While FA and the other inherited marrow failure syndromes are thought of as primarily diseases of the young, patients can present at older ages. We have therefore established a screening program for patients presenting with MDS under the age of 60, AA patients under the age of 65, and head and neck cancers under the age of 60. Patients presenting with these findings are subject to screening with telomere length testing and blood breakage testing to screen for inherited marrow failure syndromes. With this testing approach, we have identified eight patients with unrecognized inherited bone marrow defects (see Table). Five patients met the criteria for a Telomere Disease, and three patients were diagnosed with FA. Of this subset of patients, only two (20%) had physical characteristics of an inherited bone marrow disorder. In these eight patients, the treatment approach was modulated significantly, including reducing conditioning for BMT, utilizing danazol as first line treatment for AA, and aggressive cancer/endocrinopathy screening.The importance of recognizing an inheritable syndrome cannot be understated. Treatment options for these patients vary widely compared to the standard approach for acquired MDS and AA. Family members of these patients need to be screened for defects if they are potential bone marrow donors, family members are potentially at increased risk for malignancy and marrow failure, and their offspring are at increased risk of inheritance of the mutated gene. Thus, patients and their family members should be engaged in genetic counselling and encouraged to pursue screening for the inherited marrow failure disorder. Affected individuals should then undergo a comprehensive surveillance program consisting of genetic counseling, and screening for associated endocrine, genitourinary, gastrointestinal, ophthalmologic and hematologic pathology in addition to screening for solid tumors.Thus, the approach to the congenital/inherited marrow failure syndromes is bimodal. For cases that present in childhood, early recognition can lead to institution of surveillance for malignancy, blood dyscrasia, and marrow failure as well as family counseling via a genetic specialist. Similarly, recognition of delayed presentations is equally paramount, as the adult who presents with MDS, AML, or aplastic anemia is still at increased risk for solid tumors and a more aggressive transformation to a hematologic malignancy. Additionally, identifying a family member with an inheritable condition allows for screening and surveillance of unaffected, or phenotypically silent relatives, with implications ranging from simple counseling and screening, to pre-emptive treatment. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Aplastic anemia and clonal evolution: germ line and somatic genetics.

Clonal progression to myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) remains a dreaded complication for a subset of patients with bone marrow failure (BMF). Recognizing risk factors for the development of MDS or AML would inform individualized treatment decisions and identify patients who may benefit from early or upfront hematopoietic stem cell transplantation. Now that next-generation DNA sequencing is available in the clinical laboratory, research has focused on the implications of germ line and somatic mutations for diagnosing and monitoring patients with BMF. Most germ line genetic BMF disorders are characterized by a high propensity to develop MDS or AML. Many affected patients lack the physical stigmata traditionally associated with the inherited marrow failure syndromes. Although any single inherited marrow failure disorder is rare, multiplexed genetic sequencing that allows simultaneous evaluation of marrow failure genes en masse demonstrated that, as a group, these inherited disorders compose a significant subset (5% to 10%) of patients with BMF. Early diagnosis of a germ line genetic marrow failure disorder allows individualized monitoring and tailored therapy. Recent studies of somatic variants in marrow failure revealed a high frequency of clonal hematopoiesis with the acquisition of mutations in genes associated with MDS or AML. Investigation of somatic mutations in marrow failure revealed important insights into the mechanisms promoting clonal disease but also raised additional questions. This review will focus on the evaluation and implications of germ line and somatic mutations for the development of clonal disorders in patients with BMF. Challenges and limitations of clinical genetic testing will be explored.

Underlying undiagnosed inherited marrow failure syndromes among children with cancer.

To study the prevalence of pediatric cancer patients who have underlying inherited bone marrow failure syndrome (IBMFS), we retrospectively reviewed the medical records of newly diagnosed pediatric cancer patients at The Hospital for Sick Children from June 2009 to May 2010, focusing on clinical, laboratory, and treatment-related findings which may indicate underlying IBMFS. We found five (1.8%) patients out of 276 who had two or more findings suggestive of IBMFS. We conclude that a small fraction of patients with cancer have clinical features that indicate investigations to rule out underlying IBMFSs. A prospective study is needed to determine their prevalence.

Allogeneic hematopoietic stem cell transplantation for nonmalignant hematologic disorders using chemotherapy-only cytoreductive regimens and T-cell-depleted grafts from human leukocyte antigen–matched or –mismatched donors

ABSTRACTNonmalignant hematologic disorders (NMHD) of childhood comprise a variety of disorders, including acquired severe aplastic anemia and inherited marrow failure syndromes. Patients with high-risk NMHD without matched related donors fare poorly with allogeneic hematopoietic alternative donor stem cell transplantation (allo-HSCT) and are at high risk for developing graft-versus-host disease following unmodified grafts. The authors retrospectively analyzed data on 18 patients affected by NMHD, lacking a human leukocyte antigen (HLA)-identical sibling donor, who underwent an alternative donor allo-HSCT at their institution between April 2005 and May 2013. Fifty percent of the patients had received prior immunosuppressive therapy, 72% had a history of infections, and 56% were transfusion dependent at the time of transplant. Cytoreduction included a combination of 3 of 5 agents: fludarabine, melphalan, thiotepa, busulfan, and cyclophosphamide. Grafts were T-cell depleted. All evaluable patients engrafted. Five died of transplant complications. The cumulative incidence of graft-versus-host disease was 6%. No patient had recurrence of disease. Five-year overall survival was 77%. Age at transplant <6 years was strongly associated with better survival. Based on these results, transplant with chemotherapy-only cytoreductive regimens and T-cell-depleted stem cell transplants could be recommended for patients with high-risk NMHD, especially at a younger age.

The North American Shwachman-Diamond Syndrome Registry: Genetically Undefined Shwachman-Diamond Syndrome

Shwachman-Diamond syndrome (SDS) is an inherited marrow failure syndrome associated with exocrine pancreatic dysfunction and an increased risk of myelodysplasia and leukemia. The majority of individuals with SDS carry biallelic SBDS gene mutations, however a subset of patients remain genetically undefined. The objective of this study was to compare the clinical characteristics of patients with and without SBDS mutations. To address these questions, we conducted a retrospective study of patients enrolled on the North American Shwachman-Diamond Syndrome Registry (SDSR). Clinical data from the SDSR were available for 55 individuals with biallelic SBDS mutations and 16 individuals who fulfilled clinical diagnostic criteria for SDS but lacked biallelic mutations in the SBDS gene. Study subject ages for SBDS mutation positive and negative cohorts span 2-52.4 and 2.8-21.4 years with median ages of 12.4 and 10.9 years respectively. Cytopenias were present for both SBDS mutation positive and negative cohorts, with neutropenia the most common event in 94% and 81% respectively. Bone marrow hypocellularity was reported in 91% of those with SBDS mutations and 69% of those without. Marrow dysplasia was reported in 65% of those with SBDS mutations and none of those without. Clonal abnormalities were present in 44% and 25% of those with and without SBDS mutations with median age of initial appearance at 9 years (0.8-45.1) and 7 years (1.2-14) respectively. Abnormalities included del7q and del20q in both groups as well as iso7q, trisomy 8 and others in the SBDS mutation positive group. Clonal abnormalities were all transient in the SBDS mutation negative cohort. One SBDS mutation positive individual developed AML. None of the SBDS mutation negative individuals developed malignancy or progressed to require HSCT thus far. Pancreatic dysfunction determined by low serum trypsinogen or pancreatic isoamylase was similar in both cohorts 79% vs 80%. However, only 27% (15/55) of SBDS mutation positive individuals reported requiring enzyme therapy with 33% (18/55) documenting failure to thrive, in contrast to 75% (12/16) of SBDS mutation negative individuals with 73% (11/15) having failure to thrive. A broad spectrum of congenital anomalies were reported in 55% and 56% of SBDS mutation positive and negative individuals respectively, with skeletal anomalies being the most common in both groups. Medical comorbidities commonly reported in both groups included eczema and endocrinopathies. Elevated liver transaminases were seen in 27% of SBDS mutation positive individuals but this was not seen in the SBDS mutation negative cohort.Conclusion: Patients with genetically undefined (SBDS mutation negative) SDS share clinical characteristics with SBDS mutation positive patients; however, the risk of leukemia in the genetically undefined patients remains unclear due to low patient numbers with short follow-up. Further studies of this young cohort are required to inform medical management and to advance our understanding of genetic etiology, mechanism, disease pathophysiology and treatment of these marrow failure disorders. DisclosuresDale:Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau.

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

Diamond-Blackfan anemia (DBA), an inherited marrow failure syndrome, has severe hypoplastic anemia in infancy and association with aplastic anemia, MDS/leukemia, and other malignancies. Short stature is present in most patients. Isolated cases have demonstrated improved growth on growth hormone (GH) therapy. GH treatment data were obtained from 19 children with DBA (6 at our site and 13 from Genentech). Control data from 44 non-GH treated children were provided by Diamond Blackfan Anemia Registry. Annual growth velocity (GV) and height-for-age Z-scores (HAZ) were compared between groups and for up to 4y of GH treatment. Constructed DBA-specific male and female height-for-age charts for non-GH treated patients revealed short stature compared to CDC norms. GH-treated patients had significantly lower HAZ prior to treatment initiation compared to non-GH-treated controls. Among GH-treated patients, GV significantly improved in the first two years relative to pre-treatment. HAZ significantly improved in each of 4y of GH therapy compared to baseline. After 2y of therapy, HAZ for GH-treated patients were not significantly different from controls, demonstrating successful catch-up growth. GH treatment in children with DBA improves both GV and HAZ during treatment sustained for up to 4y. Very short children with DBA can be treated successfully with GH to restore stature to levels comparable to less affected patients. DBA height charts are useful tools for assessing age-specific growth in this typically short population. Careful consideration of individualized benefit of GH therapy versus risk is important in view of long-term underlying ∼5% malignancy risk in DBA.

Clinical Spectrum and Molecular Pathophysiology of Shwachman-Diamond Syndrome

Shwachman-Diamond Syndrome (SDS) is an inherited marrow failure syndrome associated with exocrine pancreatic dysfunction and leukemia predisposition. SDS patients may also manifest additional non-hematologic abnormalities. Autosomal recessive mutations in the SBDS gene are found in over 90 percent of patients fitting the classical clinical phenotype of SDS. The advent of genetic testing has revealed an unexpectedly broad range of SDS phenotypes. Through the Shwachman-Diamond Syndrome Registry, we found that diagnosis may be obscured by cryptic or non-classical presentations of SDS. The timely diagnosis of SDS carries profound ramifications for medical management and treatment. We are developing assays utilizing massively parallel next generation sequencing to address this challenging diagnostic problem. Clinical applications of next generation sequencing to the diagnostic algorithm for marrow failure or myelodysplastic syndrome and implications for medical treatment will be explored. Disclosures:No relevant conflicts of interest to declare.

Comprehensive Genomic Evaluation For Inherited Bone Marrow Failure/Myelodysplastic Syndromes

▪Accurate and timely diagnosis of inherited bone marrow failure syndromes and inherited myelodysplastic syndromes (iBMFS/iMDS) is essential to guide optimal medical management and treatment. Their early diagnosis allows appropriate clinical monitoring to initiate hematopoietic stem cell transplantation (HSCT) prior to the development of leukemia, which carries a poor prognosis in these patients. Additionally these inherited syndromes typically do not respond to standard medical therapies for aplastic anemia (i.e. ATG and cyclosporine) and are associated with excessive toxicity with standard HSCT conditioning regimens. The recognition of an inherited disorder also informs donor selection as it allows unambiguous identification of affected siblings. Currently, testing of individual genes for iBMFS/iMDS is guided by clinical suspicion. Therefore, diagnosis is easily missed in patients with cryptic presentations. Moreover, sequential genetic testing is often cost-prohibitive and may not be completed within a clinically useful timeframe.To address these clinical challenges, we developed a targeted gene capture pool coupled with next generation sequencing for the exons and flanking intronic sequences of 108 genes implicated in inherited and acquired marrow failure and MDS. Median base coverage was 192X, with 94.5% of targeted bases having >50x coverage and 99.6% of targeted bases having >10X coverage. This level of coverage together with our bioinformatic pipeline enabled identification of mutations spanning all classes (point mutations, small insertions and deletions, copy number variants, and genomic rearrangements). Rigorous criteria were applied to identify functionally deleterious mutations. Mutations were validated by conventional Sanger sequencing. Both germline and acquired mutations could be discerned, depending on DNA source (fibroblasts, peripheral blood or marrow mononuclear cells). The assay was validated with a blinded analysis of 12 patients harboring known mutations spanning different mutation classes. All mutations were successfully identified, including discerning mutations in genes from those in cognate pseudogenes.We next tested for cryptic presentations of iBMFS/iMDS in 71 patients with idiopathic marrow failure. Fifty-nine subjects were drawn from the pediatric clinic and 12 from the adult clinic. Patients previously diagnosed with a known iBMFS/iMDS were excluded from this analysis. Twenty seven of the 71 subjects (38%) had a family history suggestive of an inherited marrow failure syndrome. Diagnoses of iBMFS/iMDS were made in 7 patients (10%), of whom only 2 patients had a history suggestive of familial marrow failure. An additional 4 patients had possible mutations in iBMFS/iMDS genes (TINF2 and SRP72) with functional validation pending. Deleterious mutations in GATA2 were identified in 4 patients (6%). Four additional patients had deleterious mutations in RUNX1 of which 2 were constitutional and 2 were somatically acquired. The diagnosis had previously been missed by clinical laboratory testing of these genes in 2 patients, possibly due to technical limitations of standard approaches. One additional patient with marrow failure had pathogenic mutations in a DNA repair gene not previously reported to cause iBMFS/iMDS. These data demonstrate the utility of this unbiased approach to diagnose patients irrespective of prior clinical preconceptions. The diagnosis of iBMFS/iMDS in 2 of the 12 adult patients highlights the need to consider inherited syndromes in adults with idiopathic marrow failure. More broadly, our results draw attention to the large number of patients (85-90%) remaining genetically undefined despite comprehensive screening for mutations in known iBMFS/iMDS genes.In summary, we have developed and applied a comprehensive genomic approach to diagnose iBMFS/iMDS in 10% of patients presenting with idiopathic marrow failure. Mutations in GATA2 or RUNX1 were the most common causes of idiopathic marrow failure. Testing should be considered in both pediatric and adult patients even in the absence of prior family history. This unbiased diagnostic approach has revealed previously unexpected phenotypic features of these disorders. This efficient and cost-effective (<$400 reagents/sample) clinical diagnostic assay allows comprehensive unbiased screening for cryptic presentations of iBMFS/iMDS. Disclosures:No relevant conflicts of interest to declare.

Variable Clinical Presentation of Shwachman-Diamond Syndrome: Update From the North-American Shwachman-Diamond Syndrome Registry.

AbstractAbstract 2367 Background:Shwachman-Diamond syndrome (SDS) is an autosomal recessively inherited marrow failure syndrome associated with exocrine pancreatic dysfunction and an increased leukemia risk. SDS is caused by biallelic mutations in the SBDS gene. Timely diagnosis prior to the development of life-threatening complications is essential for optimal medical management and outcomes. SDS hematologic complications such as severe marrow failure or leukemia are treated with a hematopoietic stem cell transplant. SDS patients require reduced intensity conditioning regimens to avoid undue regimen-related toxicities, thus the recognition of the underlying diagnosis of SDS is critical. The common constellation of clinical characteristics reported for SDS includes neutropenia, steatorrhea, and failure to thrive. Hypothesis:With the advent of genetic testing, diagnosis is now possible for patients with non-classical presentations of the inherited marrow failure syndromes. The aim of this study was to investigate the range of clinical presentations for SDS with the long-term goal of improving diagnosis. Methods:This study was a retrospective review of medical records obtained by the North American Shwachman-Diamond Syndrome Registry (SDSR) which was founded in 2008. The SDS Registry works in partnership with the Severe Chronic Neutropenia International Registry. Results:Genetic reports of biallelic SBDS mutations confirming the diagnosis of SDS were available for 31 patients. This SDS study cohort included 19 male and 12 female patients. Median patient age was 10 years with a range of 2 – 49 years. Radiologic reports were available for 23 patients. Pancreatic lipomatosis was noted in 22/23 patients. One patient had an atrophic pancreas without lipomatosis on CT scan at age 6.9 years. Two patients initially had normal early pancreatic studies by CT or ultrasound at ages 1.3 years and 2.6 years, but subsequently were found to have pancreatic lipomatosis by the same imaging modalities later in life. Fecal elastase has not been previously evaluated as a screen for SDS. 14/17 patients (82%) had low fecal elastase levels while 3/17 patients had normal fecal elastase levels. Serum trypsinogen or pancreatic isoamylase were low in all 18 patients tested. 26/31 patients (84%) presented with failure to thrive. 17/31 (54%) patients presented with diarrhea or steatorrhea. 17/31 patients (55%) had congenital anomalies. Neutropenia was the most common hematologic abnormality at presentation (77%). Strikingly, 2 patients presented with isolated thrombocytopenia, 3 patients presented with severe anemia requiring transfusion support, and 5 patients presented without any cytopenias. One patient presented with the initial diagnosis of MDS with a del 20q clone. One patient presented with short stature and a sibling who died from AML. Interestingly, one patient had very short telomeres (<1st percentile for age) across 3 lymphocyte subsets as well as in total lymphocytes, a pattern typically associated with dyskeratosis congenita. Conclusion:Data from the North-American Shwachman Diamond Syndrome Registry reveals an unexpected range of clinical presentation for this rare disorder that expands beyond that which is currently classically recognized. The diagnosis of SDS should be considered even in the absence of neutropenia or diarrhea. In our cohort, clues to the underlying diagnosis of SDS included other cytopenias, congenital anomalies, family history, and the del20q clonal marrow abnormality. Reliance on classical clinical descriptions of SDS would miss or delay diagnosis of a significant subset of SDS patients. Disclosures:Dale:AMGEN: Consultancy.

Clinical approach to marrow failure

The treatment and medical management of aplastic anemia fundamentally differ between patients with inherited versus acquired marrow failure; however, the diagnosis of an inherited bone marrow failure syndrome is frequently obscure. Recent exciting advances in our understanding of the molecular pathophysiology of the inherited bone marrow failure syndromes have resulted in a profusion of new tests to aid in diagnosis. This in turn has raised questions regarding the appropriate choice of testing for the patient presenting with aplastic anemia. Important clues to the diagnosis of an inherited marrow failure syndrome may be gleaned from careful attention to the clinical history, physical exam, and laboratory workup.

Disease progression in recently diagnosed patients with inherited marrow failure syndromes: A Canadian inherited marrow failure registry (CIMFR) report

Inherited bone marrow failure syndromes (IMFSs) are genetic disorders characterized by defective single-lineage or multi-lineage hematopoiesis. IMFS patients are at risk for severe cytopenias, development of marrow cytogenetic abnormalities (MCA), myelodysplasia (MDS), and malignancy. The rate of disease progression and proportion of patients at risk for these complications is currently unclear. We examined recently diagnosed IMFS patients to determine distribution of diagnoses, disease progression and development of significant outcomes. The CIMFR is a prospective multi-center study established in 2001 to register all IMFS patients in Canada. Analysis was restricted to patients diagnosed after November 30, 1997. Summary statistics were used to depict the study population while survival was described using the Kaplan-Meier method. 74 CIMFR patients were considered recently diagnosed. Median age at diagnosis was 2.7 years (range, birth to 40.6). Annual follow-up data were available for 53 (72%) patients. The five most prevalent diagnoses were Fanconi anemia (FA), Shwachman-Diamond syndrome (SDS), Diamond-Blackfan anemia (DBA), dyskeratosis congenita (DKC), and Kostmann's neutropenia (KS). Eighteen (24%) patients were unclassifiable. Twenty-eight (53%) follow-up patients had disease progression as indicated by new or worsening cytopenias, new marrow changes, or initiation of transfusion support and/or medical therapy. Fourteen (19%) fulfilled minimal diagnostic criteria for myelodysplasia. Eleven patients had hematopoietic stem cell transplantation (HSCT) by first follow-up. Five patients have died. Survival at 36 months is 89.8 +/- 5.7%. IMFS patients are often diagnosed at a young age. The relative distribution of diagnoses is similar to previous reviews of published cases; however, 25% of patients are currently unclassifiable. Disease progression has occurred in approximately 50% of follow-up patients. Early mortality is noted. Continued prospective observation of these patients is warranted.

Inherited Bone Marrow Failure Syndromes: Molecular Features

Recent advances resulting from the identification of the genes responsible for four inherited marrow failure syndromes, Fanconi anemia, dyskeratosis congenita, Diamond-Blackfan anemia, and Shwachman-Diamond syndrome, are reviewed. The interpretation of genetic testing should be guided by an understanding of the limitations of such testing for each disorder. The possibility of an inherited basis for marrow failure must be considered for adults as well as children with aplastic anemia. Shared molecular themes are emerging from functional studies of the genes underlying the different inherited disorders. Genomic instability may result from impaired DNA repair in Fanconi anemia or telomere dysregulation in dyskeratosis congenita. Mutations affecting ribosome assembly or function are associated with Diamond-Blackfan anemia, dyskeratosis congenita, and Shwachman-Diamond syndrome. These findings raise new questions about the molecular mechanisms regulating hematopoiesis and leukemogenesis. Clinical implications arising from these molecular studies are explored.

Effect of stem cell factor on in vitro erythropoiesis in patients with bone marrow failure syndromes

Stem cell factor (SCF) enhances normal hematopoiesis. We examined its effect in vitro on bone marrow and blood progenitors from patients with inherited bone marrow failure syndromes, including 17 patients each with Diamond-Blackfan anemia (DBA) and Fanconi's anemia (FA), 3 with dyskeratosis congenita (DC), and 1 each with amegakaryocytic thrombocytopenia (amega) and transient erythroblastopenia of childhood (TEC). Mononuclear cells were cultured with erythropoietin (Ep) alone or combined with SCF or other factors. SCF increased the growth of erythroid progenitors in cultures from 50% of normal controls, 90% of DBA, 70% of FA, 30% of DC, and the amega and TEC patients; normal numbers were reached in 25% of DBA studies. Improved in vitro erythropoiesis with SCF in all types of inherited marrow failure syndromes does not suggest a common defect involving kit or SCF, but implies that SCF may be helpful in the treatment of hematopoietic defects of varied etiologies.

Effect of Stem Cell Factor on In Vitro Erythropoiesis in Patients With Bone Marrow Failure Syndromes

Stem cell factor (SCF) enhances normal hematopoiesis. We examined its effect in vitro on bone marrow and blood progenitors from patients with inherited bone marrow failure syndromes, including 17 patients each with Diamond-Blackfan anemia (DBA) and Fanconi's anemia (FA), 3 with dyskeratosis congenita (DC), and 1 each with amegakaryocytic thrombocytopenia (amega) and transient erythroblastopenia of childhood (TEC). Mononuclear cells were cultured with erythropoietin (Ep) alone or combined with SCF or other factors. SCF increased the growth of erythroid progenitors in cultures from 50% of normal controls, 90% of DBA, 70% of FA, 30% of DC, and the amega and TEC patients; normal numbers were reached in 25% of DBA studies. Improved in vitro erythropoiesis with SCF in all types of inherited marrow failure syndromes does not suggest a common defect involving kit or SCF, but implies that SCF may be helpful in the treatment of hematopoietic defects of varied etiologies.