Pediatric Myelodysplastic Syndrome Research Articles

Efficient and novel multidomain feature analysis model with incremental optimizations for enhancing pediatric myelodysplastic syndrome detection

Pediatric myelodysplastic syndromes (MDS) are complicated, thus early and accurate diagnosis is essential for treatment planning and patient care. Diagnostic processes often use discrete data domain analysis, which reduces accuracy and delays diagnosis. This work addresses these limitations by introducing an advanced Multi domain Feature Analysis Model (MFAM) enhanced with incremental optimizations to improve pediatric MDS detection. Traditional pediatric MDS diagnosis relies on subjective evaluations and limited data fusion, not modern computational methods. These constraints may reduce diagnosis accuracy and postpone action. The proposed MFAM integrates data from Clinical History, Physical Examination, Blood Cell Counts, Peripheral Blood Smear, Bone Marrow Aspiration and Biopsy, Cytogenetic Analysis, Flow Cytometry, Genetic Testing, Iron Studies, and Bone Marrow Cytology to overcome these challenges. The MFAM increases feature variance by fusing Bidirectional Long Short-Term Memory (BiLSTM) with Bidirectional Gated Recurrent Units (BiGRU). Deep Q Learning with Graph Recurrent Convolutional Neural Networks (DQGRCNN) boosts efficiency. Additionally, the model integrates the Vector Autoregressive Moving Average with Exogenous Inputs (VARMAX) to facilitate early prediction of paediatric MDS. These enhancements have resulted in significant improvements in the precision of paediatric MDS detection by 4.5%, accuracy by 3.5%, recall by 2.3%, Area Under the Curve (AUC) by 1.5%, and specificity by 2.4% while reducing diagnostic delays by 8.5%. Furthermore, the model enhances the precision of predictive analysis by 2.9%, accuracy by 3.5%, recall by 2.5%, AUC by 2.9%, specificity by 5.5%, and reduces delays in predictive analysis by 8.5%. The MFAM presented in this paper revolutionizes the diagnosis and treatment of paediatric MDS by efficiently combining diverse diagnostic data, employing advanced transformation and fusion techniques, and optimizing responses through DQGRCNN. The integration of VARMAX further enables early prediction of the disease. MFAM will enhance diagnostic precision, therapy start, and clinical outcomes for young MDS patients.

UBTF tandem duplications in pediatric myelodysplastic syndrome and acute myeloid leukemia: implications for clinical screening and diagnosis.

Recent genomic studies in adult and pediatric acute myeloid leukemia (AML) demonstrated recurrent in-frame tandem duplications (TD) in exon 13 of upstream binding transcription factor (UBTF). These alterations, which account for approximately 4.3% of AML in childhood and about 3% in adult AML aged <60 years of age, are subtype-defining and associated with poor outcomes. Here, we provide a comprehensive investigation into the clinicopathological features of UBTF-TD myeloid neoplasms in childhood, including 89 unique pediatric AML and 6 myelodysplastic syndrome (MDS) cases harboring a tandem duplication in exon 13 of UBTF. We demonstrate that UBTF-TD myeloid tumors are associated with dysplastic features, low bone marrow blast infiltration, and low white blood cell count. Furthermore, using bulk and single-cell analyses, we confirm that UBTF-TD is an early and clonal event associated with a distinct transcriptional profile, whereas the acquisition of FLT3 or WT1 mutations is associated with more stem cell-like programs. Lastly, we report rare duplications within exon 9 of UBTF that phenocopy exon 13 duplications, expanding the spectrum of UBTF alterations in pediatric myeloid tumors. Collectively, we comprehensively characterize pediatric AML and MDS with UBTF-TD, and highlight key clinical and pathologic features that distinguish this new entity from other molecular subtypes of AML.

The role of genetic factors in pediatric myelodysplastic syndromes with different outcomes

BackgroundPediatric myelodysplastic syndromes (MDS) are rare disorders with an unrevealed pathogenesis. Our aim is to explore the role of genetic factors in the pathogenesis of MDS in children with different outcomes and to discover the correlation between genetic features and clinical outcomes as well as disease characteristics.MethodsWe conducted an analysis of archived genetic data from 26 patients diagnosed with pediatric MDS at our institution between 2015 and 2021, examining the association between different genetic characteristics and clinical manifestations as well as prognosis. Additionally, We presented three cases with distinct genetic background and outcomes as examples to elaborate the role of genetic factors in pediatric MDS with different prognoses.ResultsGenetic variations were detected in 13 out of the 26 patients, including 8 patients with co-occurrence of somatic and germline mutations (CSGMs) and 5 patients with somatic mutations alone. Our analysis revealed that advanced MDS (4/8, 50% vs. 1/5, 20% and 4/11, 36.4%), PD (3/8, 37.5% vs. 1/5, 20% and 1/11 9.1%), and TD (6/8, 75% vs. 2/5, 40% and 2/11, 18.2%) were more common in patients with CSGMs than those with somatic mutations alone or without any mutations. We also found out in our study that 8 patients with CSGMs had evidently different clinical outcomes, and we presented 3 of them as examples for elaboration. Case 1 with germline and somatic mutations of unknown significance had a relatively slow disease course and a good prognosis. Case 2 with compound heterozygous germline SBDS variants and somatic mutations like del20q had a stable disease course and a reversed outcome. Case 3 with a germline GATA2 variant and somatic mutations including − 7 had a rapidly progressive disease course and a worst prognosis.ConclusionOur findings indicate that genetic background of pediatric MDS is closely linked with disease characteristics as well as outcomes and that CSGMs may lead to disease progression. It should be emphasized that the interaction between certain germline variants and somatic mutations, such as SBDS and del20q, may result in hematopoietic stem cell adaptation (improved hematopoiesis) and reversed clinical outcomes, which can facilitate the development of targeted therapy.

Association between Leukemic Evolution and Uncommon Chromosomal Alterations in Pediatric Myelodysplastic Syndrome.

Pediatric myelodysplastic syndrome (pMDS) is a group of rare clonal neoplasms with a difficult diagnosis and risk of progression to acute myeloid leukemia (AML). The early stratification in risk groups is essential to choose the treatment and indication for allogeneic hematopoietic stem cell transplantation (HSCT). According to the Revised International Prognostic Scoring System, cytogenetic analysis has demonstrated an essential role in diagnosis and prognosis. In pMDS, abnormal karyotypes are present in 30-50% of the cases. Monosomy 7 is the most common chromosomal alteration associated with poor prognosis. However, the rarity of specific cytogenetic alterations makes its prognosis uncertain. Thus, this study aimed to describe uncommon cytogenetic alterations in a cohort of 200 pMDS patients and their association with evolution to AML. The cytogenetic analysis was performed in 200 pMDS patients by G-banding and fluorescence in situ hybridization between 2000 to 2022. Rare chromosome alterations were observed in 7.5% (15/200) of the cases. These chromosome alterations were divided into four cytogenetic groups: hyperdiploidy, biclonal chromosomal alterations, translocations, and uncommon deletions representing 33.3%, 33.3%, 20%, and 13.3%, respectively. Most of these patients (10/15) were classified with advanced MDS (MDS-EB and MDS/AML) and the initial subtype was present in five patients (RCC). The leukemic evolution was observed in 66.66% (10/15) of the patients. Most patients had poor clinical outcomes and they were indicated for HSCT. The study of uncommon cytogenetic alterations in pMDS is important to improve the prognosis and guide early indication of HSCT.

The different faces of GATA2 deficiency: implications for therapy and surveillance.

GATA2 deficiency is one of the most common genetic predispositions to pediatric myelodysplastic syndrome (MDS) in children and adolescents. The wide spectrum of disease comprises, among others, hematological, immunological and pulmonary manifestations, as well as occasionally distinct organ anomalies. Due to the elevated risk of progression, nearly all individuals with GATA2-related MDS eventually undergo a hematopoietic stem cell transplantation (HSCT) at some point in their lives. Nevertheless, the optimal timing, method, and even the indication for HSCT in certain cases are still matter of debate and warrant further research. In this article, we report five patients with different hematological and immunological manifestations of GATA2 deficiency ranging from immunodeficiency and refractory cytopenia of childhood without chromosomal aberrations to relapsed MDS-related acute myeloid leukemia. We discuss the adopted strategies, including intensity of surveillance, indication and timing of HSCT, based on morphological, clinical and molecular markers, as well as individual patient needs. We conclude that a better characterization of the natural disease course, a better understanding of the prognostic significance of somatic aberrations and a thorough evaluation of patients´ perspectives and preferences are required to achieve a personalized approach aimed at improving the care of these patients.

The Efficacy and Prognosis of Advanced Myelodysplastic Syndrome in Children

Pediatric myelodysplastic syndrome (MDS) is a clonal hematopoietic stem cell neoplasm with an annual incidence of 1-4 cases/million. The low incidence of advanced MDS in children and poor prognosis attract our attention. However, there are limited reports on the scheme and efficacy of pediatric advanced MDS. In this study, we retrospectively analyzed the efficacy of chemotherapy in pediatric advanced MDS and assessed the prognosis of patients. According to 2016 World Health Organization (WHO) classification of haematolymphoid tumours, 30 newly diagnosed pediatric advanced MDS patients during Dec 2007 to Apr 2022 from our single center were selected as the research object. The clinical data and prognosis were analyzed. The median age of patients is 8 years (range: 1-15years). The median bone marrow blast is 15.75% (range: 5-29.5%), while the median peripheral blood blast is 4% (range: 0-29%). Cytogenetic analysis was available for 29 patients, 69% (20/29) cases had abnormal karyotype. Monosomy 7 (37.9%) was the most common cytogenetic abnormality. Out of the total, 7 patients were treated with CAG/HAG regimen (C: aclarubicin 6mg d1-14, H: homoharringtonine 1mg/m 2d1-14, A: cytarabine 10mg/m 2 q12h d1-14, and G: Granulocyte Colony-stimulating Factor 200mg/m 2 d1-14 ), 8 patients with decitabine (20mg/m 2 d1-5), 11 patients with decitabine and CAG/HAG, 4 patients with AML-like chemotherapy (Daunorubicin+cytarabine+etoposide ) or other. The evaluation of response of therapy was available in 25 patients, 5 cases (20%) in partial remission (PR), 11 cases (44%) in complete remission (CR), 9 cases in(36%)non-remission (NR). The total response rate of chemotherapy is 60%, with CAG/HAG therapy 33%, decitabine therapy 43%, combined CAG/HAG and decitabine therapy 78%, AML-like chemotherapy 100%. The total complete remission rate of chemotherapy is 44%, with CAG/HAG therapy 17%, decitabine therapy 43%, combined CAG/HAG and decitabine therapy 56%, AML-like chemotherapy 67%. Patients receiving CAG/HAG in combination with decitabine had higher response rates compared to CAG/HAG or decitabine alone (OR=17.5, 95% CI 1.2-250.3, P=0.035). With a median follow-up of 20 months (range: 1-158months), 23 patients received HSCT after chemotherapy, and they had a higher 2-year overall survival rate compared to those who did not undergo transplantation (86% vs 0%, p&amp;lt;0.001). Decitabine combined with CAG/HAG improve the response rate of advanced pediatric MDS. Chemotherapy bridged hematopoietic stem cell transplantation significantly improves the prognosis of advanced pediatric MDS.

Interest of Cytoreductive Therapy before Allogenic Hematopoietic Stem Cell Transplantation in Childhood Myelodysplastic Syndromes: A Retrospective Study on Behalf of the Société Francophone De Greffe De Moelle Et De Thérapie Cellulaire (SFGM-TC)

Background: Pediatric myelodysplastic syndromes (cMDS) are rare and biologically different from that seen in adults. In addition to a specific genomic landscape, they are characterized by the high frequency of hypoplastic forms, and the recurrent association with germline predispositions (Khoury et al. 2022; Locatelli et Strahm 2018). For most patients, allogenic hematopoietic stem cell transplantation (allo-HSCT) remains the only curative option. In case of cMDS with increased blasts (cMDS-IB), pre-tranplant cytoreductive chemotherapy may be considered, but remains controversial (Strahm et al. 2011). Methods This multicenter retrospective study included all cMDS patients (&amp;lt;18y.o.) reported to the SFGM-TC registry who underwent an allo-HSCT between 2000 and 2020. Data have been obtained through ProMISe (internet-based system shared by all EBMT transplantation centers). All patients have given signed informed consent. Results Eighty-four cMDS patients from 17 centers were included. Median age at transplant was 10.2 years (IQR: 7.2, 14.2). Fifty-two percent of patients presented with increased blasts at diagnosis. Germline predispositions were known in 24% of patients. GATA 2 mutations were the most frequent (14%). Eighty-two percent of patients presented with hematologic cytogenetic abnormalities, including 64% of monosomy 7. Myeloablative conditioning was used in most of cases (91%). Busulfan/melphalan was the most frequent conditioning regimen (58%). HSCT were performed from sibling donors in 29% of the cases, matched unrelated donors (MUD) in 44%, umbilical cord blood (UCB) in 21% and haploidentical in 6%. Stem cell source was bone marrow in 68% of the cases. Considering the whole cohort, 5y overall survival (OS) and disease-free survival (DFS) were 67% (IC95% 57-78%) and 63% (IC95% 54-74%) respectively (Figure 1). Five years cumulative incidences of non-relapse mortality (NRM) and relapse were 26% (IC95% 17-35%) and 12% (IC95% 5.6-20%) respectively. Of the 21 cases of reported toxic death, 15 were related to acute GVH (aGVHD). Six months cumulative incidences of grade II-IV and III-IV acute graft vs host disease were 46 % and 24 % respectively. In univariate analysis, patients under 12 years (p=0,018) or who received a BuCyMel conditioning (p=0,004) or a graft from a MUD (p=0,030) had worst 5y OS and PFS. As expected, OS increased with time (p=0,014) reflecting improvements in supportive care and HSCT procedures (Figure 2A). These results were confirmed in multivariate analysis, except for MUD. Twenty-four patients received pre-transplant cytoreductive therapy, most often intensive chemotherapy (20/24). In the overall population, pre-transplant cytoreduction was not associated with an improved survival. However, subgroup analysis of the 40 patients with cMDS-IB showed a significant improvement of the OS probability (HR 0.18 [0.04-0.83], p=0.014) in patients who received a pre-transplant cytoreductive therapy in univariate analysis (Figure 2B). Cytoreductive therapy did not appear to be associated with a reduced risk of relapse, but with a lower risk of NRM. Although not statistically significant, the incidence of aGVHD was higher in patients who did not receive any cytoreductive therapy (HR 0.60 [0.09-3.85]). Conclusion: This retrospective study reports the outcomes of 84 patients who underwent allo-HCT for childhoodMDS. This study seems to show a benefit associated with the pre-transplant cytoreduction therapy in the subgroup of patients with cMDS-IB, notably through a reduction of aGVHD and NRM occurrence. BuCyMel conditioning, currently recommended for cMDS-IB, appears here, to be associated with excess of toxic mortality. This study also confirms the high aGVH-related toxic mortality rates already reported in cMDS (Strahm et al. 2011). Recent retrospective data have shown a benefit of post-transplantation cyclophosphamide (PTCy) in GATA2 patients transplanted with sibling or matched unrelated donors (Nichols-Vinueza et al. 2022). Prospective data on the use of PTCy in cMDS are therefore needed. Acknowledgment: This research is funded by the non-profit organization Etoile de Martin/SFCE.

Bone Marrow, Laboratory, and Clinical Features in Pediatric Patients with RUNX1 Familial Platelet Disorder with Associated Myeloid Malignancy (FPDMM)

Background: Germline RUNX1 mutation is associated with an autosomal dominant familial platelet disorder with associated myeloid malignancy (FPDMM), most commonly myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), but lymphoblastic leukemias are also reported. FPDMM is characterized by thrombocytopenia from an early age associated with abnormal platelet function. Herein we report the bone marrow features, in addition to laboratory and clinical findings, of a large pediatric cohort (N=29) with RUNX1-FPDMM. These data have value in guiding early investigation of neonatal/pediatric thrombocytopenia, and baseline bone marrow interpretation to avoid overdiagnosis of MDS or misdiagnosis of immune-mediated thrombocytopenias. Design: The clinical, laboratory, bone marrow pathology, and molecular findings of 29 pediatric patients (&amp;lt;18 years) with germline RUNX1 mutation followed by the natural history study at the National Institutes of Health (NIH) (ClinicalTrials.gov Identifier: NCT03854318), were analyzed. Results : Among the patients, 13 were female and 16 male, in 21 pedigrees, with a median age at bone marrow biopsy of 6 years (range: 17 months to 17 years). Germline RUNX1 mutations were familial in 26 patients and de novo in 3 patients. Easy bruising and propensity for bleeding were common (87%). The median platelet count was 123 x 10 9/L (range: 38 - 244). Abnormal platelet aggregation assay was present in all 9 patients tested. Abnormal transmission electron microscopy of platelets was found in 14/21 (67%) patients tested; the majority had decreased platelet dense granules, with or without decreased alpha granules. Three patients had normal platelet counts. Hematologic neoplasm was identified in 4 patients: one with AML with JAK3 and KRAS mutations; one with B-lymphoblastic leukemia with EBF1::PDGFRB; one with T-lymphoblastic leukemia with a complex karyotype; and one with MDS with excess blasts and no detectable acquired genetic alterations. 3/4 of patients with malignancy had hypercellular marrows. Of the remaining patients, 19/25 (76%) had hypocellular bone marrows for age. The majority had normal numbers of megakaryocytes. Dysmegakaryopoiesis with features overlapping with “dysplasia” (small hypolobated, small with convoluted nuclei and minimal cytoplasm, separation of nuclear lobes) in greater than 10% of megakaryocytes was present in 92% of cases. At least one patient was previously misdiagnosed with immune thrombocytopenic purpura (ITP). 18 patients had eosinophilia in bone marrow sections, six of whom had peripheral blood eosinophilia. Flow cytometric analysis of the marrow commonly showed T-cells with inverted CD4:CD8 ratios (17/22) and increased eosinophils (16/22). The one patient with MDS had increased (10%) immunophenotypically abnormal myeloblasts expressing CD7 and CD123. 23/25 patients had targeted NGS: one patient had a pathogenic mutation in BCOR and the remaining had no pathogenic mutations in genes associated with hematologic malignancy; 15 patients had VUSs reported. At least four patients had large RUNX1 deletions that were not detected by conventional NGS. 23 patients tested had a normal karyotype except one female patient with monosomy X in 11/20 metaphases. Allergy (drug, food and seasonal) was present in 11 patients, and eczema was common. A spectrum of gastrointestinal (GI) symptoms was seen in 11 patients, including constipation, eosinophilic esophagitis, gastroesophageal reflux, and celiac disease. 2 patients were diagnosed with autism, 1 with coarse facies and KDM6B mutation, 1 with brachydactyly syndrome related to PRMT7 mutation, and 1 with non-syndromic hearing loss related to GJB2 mutation. Conclusion: Germline mutation in RUNX1 should be considered in pediatric patients with thrombocytopenia and/or abnormal platelet function and a hypocellular marrow with or without dysmegakaryopoiesis. Dysmegakaryopoiesis in the setting of RUNX1-FPDMM should not be overinterpreted as pediatric MDS without other supporting criteria such as MDS-defining cytogenetic/molecular abnormalities, multilineage dysplasia, or increased blasts. Patients with large deletions in RUNX1 may be missed on routine NGS testing hence proper germline testing in an experienced laboratory is recommended if suspicion is high. Close monitoring is crucial for early identification of emerging myeloid or lymphoid malignancy.

Development of MDS in Pediatric Patients with GATA2 Deficiency: Increased Histone Trimethylation and Deregulated Apoptosis as Potential Drivers of Transformation

GATA2 deficiency is a heterogeneous, multisystem disorder associated with a high risk of developing myelodysplastic syndrome (MDS) and the progression to acute myeloid leukemia. The mechanisms underlying malignant transformation in GATA2 deficiency remain poorly understood, necessitating predictive markers to assess an individual’s risk of progression and guide therapeutic decisions. In this study, we performed a systematic analysis of bone marrow biopsies from 57 pediatric MDS patients. Focusing on hematopoiesis and the hematopoietic niche, including its microenvironment, we used multiplex immunofluorescence combined with multispectral imaging, gene expression profiling, and multiplex RNA in situ hybridization. Patients with a GATA2 deficiency exhibited a dysregulated GATA2 transcriptional network. Disease progression (GATA2-EB, n = 6) was associated with increased GATA2 mRNA levels, restored expression of the GATA2 target EZH2, and increased H3K27me3. GATA2-EB was further characterized by the high expression of the anti-apoptotic protein BCL2, a feature absent in children with a GATA2 deficiency and refractory cytopenia of childhood (GATA2-RCC, n = 24) or other pediatric MDS subgroups (RCC, n = 17; MDS-EB, n = 10). The multispectral imaging analysis of additional BCL2 family members revealed significantly elevated Mediators of Apoptosis Combinatorial (MAC) scores in GATA2-EB patients. Taken together, our findings highlight the potential drivers of disease progression in GATA2 deficiency, particularly increased histone trimethylation and dysregulated apoptosis. Furthermore, upregulated BCL2 and EZH2 and increased MAC scores provide a strong rationale for the use of venetoclax and azacitidine in therapeutic regimens for GATA2-EB.

Spontaneous remission and loss of monosomy 7: a window of opportunity for young children with SAMD9L syndrome.

Monosomy 7 is the most common cytogenetic abnormality in pediatric myelodysplastic syndrome (MDS) and associated with a high risk of disease progression. However, in young children, spontaneous loss of monosomy 7 with concomitant hematologic recovery has been described, especially in the presence of germline mutations in SAMD9 and SAMD9L genes. Here, we report on our experience of close surveillance instead of upfront hematopoietic stem cell transplantation (HSCT) in seven patients diagnosed with SAMD9L syndrome and monosomy 7 at a median age of 0.6 years (range, 0.4-2.9). Within 14 months from diagnosis, three children experienced spontaneous hematological remission accompanied by a decrease in monosomy 7 clone size. Subclones with somatic SAMD9L mutations in cis were identified in five patients, three of whom attained hematological remission. Two patients acquired RUNX1 and EZH2 mutations during the observation period, of whom one progressed to myelodysplastic syndrome with excess of blasts (MDS-EB). Four patients underwent allogeneic HSCT at a median time of 26 months (range, 14-40) from diagnosis for MDSEB, necrotizing granulomatous lymphadenitis, persistent monosomy 7, and severe neutropenia. At last follow-up, six patients were alive, while one passed away due to transplant-related causes. These data confirm previous observations that monosomy 7 can be transient in young children with SAMD9L syndrome. However, they also indicate that delaying HSCT poses a substantial risk of severe infection and disease progression. Finally, surveillance of patients with SAMD9L syndrome and monosomy 7 is critical to define the evolving genetic landscape and to determine the appropriate timing of HSCT (clinicaltrials gov. Identifier: NCT00662090).

Impact of cytoreduction and remission status on hematopoietic cell transplantation outcomes in pediatric myelodysplastic syndrome and related disorders.

The role of cytoreduction prior to hematopoietic cell transplant (HCT) for patients with pediatric myelodysplastic syndrome (MDS) and related disorders remains unclear. We performed a single-center retrospective analysis of pre-transplant disease management and subsequent HCT outcome for pediatric patients with MDS and related disorders who underwent HCT between 2010 and 2020. Total 62 patients (median age 11years) with idiopathic MDS (n=16), MDS secondary to an underlying germline condition (n=11), secondary acute myeloid leukemia (n=9), myeloproliferative neoplasms (n=8), and treatment-related myeloid neoplasms (n=18) received an allogeneic HCT. Cytoreduction prior to HCT was performed in 30/62 (48%) patients; this subset of patients had higher risk disease characteristics, including a higher blast count on presentation. In the overall cohort, use of cytoreduction before HCT was associated with higher rates of relapse (cumulative incidence of relapse 24months post HCT: 48.1% [27.5%-66.1%]) for those who received cytoreduction versus 16.6% (5.9%-32.1%) for those who did not (p=.03). There was a trend toward decreased overall survival (OS) for those patients who received cytoreduction (24months post HCT 57.1% vs. 75.3%, respectively; p=.06). OS for patients who received cytoreduction and attained measurable residual disease (MRD) negativity prior to HCT was superior compared to those with persistent disease (24months post HCT 63.9% [36%-81.2%] vs. 33.3% [7.8%-62.3%], respectively; p=.04). Cytoreduction did not provide survival benefit in our overall cohort, but its increased use in children with higher risk disease impacted the analysis. Patients receiving cytoreduction and achieving MRD-negative status before HCT demonstrated improved OS compared to those with persistent disease.

Juvenile myelomonocytic leukemia: A national analysis of demographic features.

e19086 Background: Juvenile Myelomonocytic Leukemia (JMML) is a rare hematological cancer originating in the bone marrow. It is a type of myelodysplastic syndrome (MDS) characterized by abnormal production of myeloid progenitor cells and monocytes. This malignancy is predominant in males, has a median age of diagnosis of 2 years, and carries a poor prognosis. It only accounts for 1% of all pediatric leukemias but constitutes 20-40% of pediatric MDS cases, making it the most common MDS subtype in children. Hematopoietic stem cell transplant (HSCT) is the only known cure for JMML, but its efficacy is just 50%. Without treatment, patients survive for a median of 10-12 months. Given the rarity of JMML, an analysis of demographic trends could offer valuable epidemiological insight. The National Cancer Database (NCDB) database was used to examine major demographic features of JMML. Methods: A retrospective analysis of all patients diagnosed with JMML between 2004 – 2020 in the NCDB (N = 242) was performed. Demographic factors including sex, race, Hispanic ethnicity, household income status, insurance status, urban/rural status, and Charlson-Deyo score were examined by descriptive statistics. Treatment statistics were also analyzed. Linear regression was used to determine incidence trends. Results: A total of 242 patients were identified with a histologically-confirmed diagnosis of JMML. Most patients were male (67.4%). The average age of diagnosis was 2 years (SD = 3.69, range = 0-33). The average incidence was 14.2 patients diagnosed per year (SD = 3.7, range = 9 – 21, R2 = 0.131). 93.8% had a Charlson-Deyo comorbidity score of 0. The majority of patients were White (74.4%), followed by Black (11.6%). 16.1% of patients were of Hispanic ethnicity. The distribution of median household income was 27.4% in the top quartile, 26.9% in the second, 26.9% in the third, and 18.7% in the fourth. Most patients were either privately insured (49.6%) or insured by Medicaid (42.6%). 75.5% of patients lived in a county with 250,000 people or more. Most patients received treatment (84.6%), while some only received active surveillance (8.7%) or no treatment (6.7%). Conclusions: This is the first NCDB analysis describing the demographic trends of JMML. Patients were twice as likely to be male than female. They were most likely to be White, with an average age of 2 years. This data reflects the expected age group and sex/race predominance described in the literature. The proportion of Hispanic JMML patients was comparable to Hispanics in the general US population. JMML appeared to be nearly evenly distributed among the top three household income quartiles. The lowest income quartile and rural inhabitants were least affected by this disease, which may indicate underdiagnosis in these populations. Further studies are needed to better define the relevance of these individual factors in the diagnosis, treatment, and survival of patients with JMML.

Pediatric myelodysplastic syndrome

Pediatric myelodysplastic syndrome

Bone marrow morphologic and neuroradiologic findings in a case of pediatric myelodysplastic syndrome arising in ataxia‐pancytopenia syndrome

Bone marrow morphologic and neuroradiologic findings in a case of pediatric myelodysplastic syndrome arising in ataxia‐pancytopenia syndrome

The International Consensus Classification (ICC) of hematologic neoplasms with germline predisposition, pediatric myelodysplastic syndrome, and juvenile myelomonocytic leukemia.

Updating the classification of hematologic neoplasia with germline predisposition, pediatric myelodysplastic syndrome (MDS), and juvenile myelomonocytic leukemia (JMML) is critical for diagnosis, therapy, research, and clinical trials. Advances in next-generation sequencing technology have led to the identification of an expanding group of genes that predispose to the development of hematolymphoid neoplasia when mutated in germline configuration and inherited. This review encompasses recent advances in the classification of myeloid and lymphoblastic neoplasia with germline predisposition summarizing important genetic and phenotypic information, relevant laboratory testing, and pathologic bone marrow features. Genes are organized into three major categories including (1) those that are not associated with constitutional disorder and include CEBPA, DDX41, and TP53; (2) those associated with thrombocytopenia or platelet dysfunction including RUNX1, ANKRD26, and ETV6; and (3) those associated with constitutional disorders affecting multiple organ systems including GATA2, SAMD9, and SAMD9L, inherited genetic mutations associated with classic bone marrow failure syndromes and JMML, and Down syndrome. A provisional category of germline predisposition genes is created to recognize genes with growing evidence that may be formally included in future revised classifications as substantial supporting data emerges. We also detail advances in the classification of pediatric myelodysplastic syndrome (MDS), expanding the definition of refractory cytopenia of childhood (RCC) to include early manifestation of MDS in patients with germline predisposition. Finally, updates in the classification of juvenile myelomonocytic leukemia are presented which genetically define JMML as a myeloproliferative/myelodysplastic disease harboring canonical RAS pathway mutations. Diseases with features overlapping with JMML that do not carry RAS pathway mutations are classified as JMML-like. The review is based on the International Consensus Classification (ICC) of Myeloid and Lymphoid Neoplasms as reported by Arber et al. (Blood 140(11):1200-1228, 2022).

T-Cell Replete Unrelated Cord Blood Transplant Give Superior Outcomes to Other Donor Sources in High Risk and Relapsed/Refractory Paediatric Myeloid Malignancy

Introduction: Outcomes of alternate donor haematopoietic stem cell transplant (SCT) in high-risk (HR) and relapsed or refractory (R/R) paediatric acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS) have been poor historically. Cord blood (CB) allows T-cell replete transplant, potentially enabling enhanced graft-versus-leukaemia (GVL) in patients with myeloid malignancies. We report the utility of T-replete CB (TRCB) transplant in high-risk paediatric myeloid malignancies in a large multi-centre national analysis, compared with patients transplanted with similar disease and at the same time using other donor sources. Methods: Data was collected from consecutive patients undergoing TRCB transplant for paediatric AML or MDS in 10 UK and Republic of Ireland paediatric bone marrow transplant centres between January 2014 and December 2021. The comparator group consisted of consecutive paediatric patients undergoing either a T-cell depleted (i.e. plus serotherapy) CB SCT or a transplant using any other cell source (matched sibling, matched/mismatched unrelated donor, or haplo-identical donor) at the same centres over the same period for the same indication. Information was gathered directly from the centre using an agreed data proforma and cross-checked for accuracy and completeness against the BSBMT/EBMT data submissions of each centre. Results: Data for 367 patients was analysed in this retrospective analysis which included 112 TRCB recipients and 255 patients in the comparator group. Median follow up was 2 years in the TRCB cohort and 4.5 years in the comparator group. All rates are quoted at 2 years. The median ages were 6.5 years in the TRCB group and 8.9 in the comparator, 91% of each group were AML. The TRCB cohort appeared to be a worse prognosis group with 51.4% of patients flow MRD positive at transplant compared with 26.1% in the comparator group (p <0.001), 46.4% had physician-defined refractory disease at transplant and 21.4% had relapsed following a previous SCT, compared with 8.6% refractory and 5.1% previous SCT in the comparator group (p<0.001 and p<0.001). Within the TRCB cohort Overall survival (OS) and Event Free Survival (EFS) were 64.7% and 64.1%, with EFS of 50% in those that were flow MRD positive at SCT and 79% for flow MRD negative patients (p= 0.009). EFS stratified by clinical disease status was 60.9% for those with primary refractory disease (n=29), 46.5% in those with relapsed refractory disease (n=23), 67% for those in high risk CR1 (n=38) and 79.6% for those in CR2 (n=22). For the 24 patients who had received a previous BMT, EFS was 69%. 67% TRCB recipients developed acute GVHD, of which 30% was grade 3-4, but the rates of chronic GVHD were very low at 5%. To allow for the imbalance in baseline characteristics, a multivariate analysis (MVA) was performed: the TRCB cohort had significantly improved EFS (0.57(0.35-0.91), p=0.019) and time to relapse (0.46(0.26-0.81), p=0.008) with some evidence of improved OS (0.65(0.39-1.07), p = 0.088). The effect appeared similar for MRD positives and negatives (interaction p=0.29 EFS and 0.67 relapse). Figures 1 and 2 highlight the strikingly superior EFS and relapse risk in the TRCB cohort for MRD positive patients in univariate analysis. Transplant-related mortality (TRM) was higher in the TRCB setting, 12% vs 7% (2.05 (1.05, 4.01), p=0.036) but rates of chronic GVHD were significantly lower with TRCB compared to other SCT types, 4.9% vs 19.4% (0.25(0.10, 0.62), p=0.003). Conclusion: This is the largest reported analysis of TRCB outcomes in HR paediatric myeloid malignancy, and we demonstrate excellent results, even in refractory disease. Our data show significantly superior outcomes for patients receiving TRCB compared with other transplant cell sources, owing to a lower relapse risk in the CB setting. This is likely to reflect enhanced GVL effects with TRCB compared with alternate donor sources requiring T-cell depletion. Despite higher TRM in the TRCB setting, when adjusted for the confounding variable of more MRD positive patients in this group, EFS and relapse are highly significant with a strong trend for improved OS. Our data suggests that CB transplant without serotherapy may be the optimal transplant option for children with HR and R/R AML/MDS, particularly with strategies to mitigate the higher TRM. This potential practice change warrants exploration in a large prospective randomised controlled trial. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Transient Monosomy 7 Is a Rare Event in Young Children with SAMD9L Syndrome

Monosomy 7 and deletion 7q are among the most common chromosomal aberrations in pediatric myeloid malignancies and generally associated with an increased risk of rapid progression to advanced neoplasia, warranting allogeneic hematopoietic stem cell transplantation (HSCT). However, several cases of transient monosomy 7 and spontaneous hematologic recovery upon loss of monosomy 7 in young children have been described in the literature. In several cases, germline mutations in sterile alpha-motif domain-containing protein 9 (SAMD9) and SAMD9-like (SAMD9L), both located on chromosome 7q, have been identified. Gain of function (GOF) mutations in SAMD9 and SAMD9L cause phenotypically overlapping syndromes that predispose to pediatric myelodysplastic syndrome (MDS) and are associated with non-hematological anomalies and variable immunodeficiency. GOF SAMD9/9L mutations inhibit cell proliferation and reduce cell survival of hematopoietic stem and progenitor cells (HSPCs). This may exert strong selection pressure on HSPCs to acquire somatic aberrations that improve their competitive fitness. To no surprise, a distinctive feature of SAMD9/9L syndromes is their propensity for somatic genetic reversion, including somatic loss of function mutations in SAMD9/9L in cis, uniparental isodisomy 7q, and non-random loss of chromosome 7 or 7q of the mutant allele. Multiple hematopoietic subclones with clone-defining somatic mutations can exist in the bone marrow and their composition may change over time due to the exceptionally high plasticity of hematopoiesis in young children. Consequently, monosomy 7 may spontaneously disappear in young patients with SAMD9/9L syndromes. Earlier observations had suggested that somatic compensatory mutations may be more frequent in SAMD9L than in SAMD9 mutated patients. Here, we investigate the natural history of young children with SAMD9L syndrome and monosomy 7. We report on seven patients with SAMD9L syndrome and monosomy 7 presenting before the age of 5 years in whom an initial surveillance strategy was electively chosen rather than timely allogeneic HSCT. All patients presented with refractory cytopenia of childhood with monosomy 7 at a median age of 1.0 years (range: 0.4-3.1 years). Six patients had an additional non-hematologic phenotype, including prematurity (P2, P5), small for gestational age (P1, P2, P7), cerebellar atrophy and developmental delay (P1), bilateral cleft lip and palate (P2), macrocephaly (P3, P6), shorter thumbs (P6), and big eye bulbs and dystrophy (P7). Immunodeficiency was present in five patients ranging from hypogammaglobulinemia (P1, P2, P5, P6, P7) to B and NK cell deficiency patients (P2, P5, P6, P7). At a median follow-up of 35 months (range: 10-51 months), allogeneic HSCT had been employed in four patients for severe neutropenia and/or bacterial infection (P1, P7), persistence of monosomy 7 beyond the age of 5 years (P5) or disease progression to MDS with excess blasts (P2). One patient (P2) suffered transplant-related mortality, while the remaining patients were alive at last follow-up. Three patients did not require definitive treatment. Two of the three patients had complete loss of the monosomy 7 clone with concomitant recovery of blood counts (P4, P6), a third patient had normalized blood counts, but cytogenetic and molecular studies at follow-up were missing (P3). Secondary somatic mutations were detected in six patients. Five patients carried somatic SAMD9L mutations in cis (P2, P3, P4, P6, P7). Two patients with spontaneous loss of monosomy 7 carried large somatic SAMD9L subclones that were stable over time and presumably maintained hematopoiesis (P4, P6). In addition, two patients carried somatic mutations in oncogenic driver genes (P2, P5). P2, who developed MDS-EB 14 months after diagnosis, had two RUNX1 mutations at the time of progression. P5 had one RUNX1 and one EZH2 mutation, but without evidence of disease progression. Our results suggest that loss of monosomy 7 can occur in young patients with SAMD9L syndrome but is a rare event. If a watch and wait strategy is chosen, close monitoring with frequent bone marrow examinations including SAMD9L sequencing, cytogenetics and search for somatic oncogenic events is advised. Importantly, presence of severe infections, severe neutropenia, increase in blast percentage, and persistence of monosomy 7 beyond the age of 5 years should prompt timely allogeneic HSCT.

Septin-6 Regulates Murine and Human Hematopoiesis, and Its Dysregulation Is Associated with Pediatric Myelodysplasia

Septin family proteins are key regulators of cytoskeletal organization and cytokinesis although little is known about their function in normal hematopoiesis. Septins are implicated in T and B cell lymphomas; and acute myeloid leukemias, where they frequently act as fusion partners with the Mixed-Lineage Leukemia (MLL) gene. Previously, we identified a non-syndromic newborn with severe neutropenia which progressed to myelodysplastic syndrome (MDS) (Renella et al. AJH, 2022). Next-generation sequencing revealed a novel X-linked germline mutation in the SEPTIN-6 gene associated with dysmyelopoiesis (SEPTIN6 c.1282T>C); and a second stop-gain somatic mutation hypothesized to rescue hematopoietic function, but the mechanism of MDS was not defined. Based on our initial publication, a second patient with neutropenia/MDS has since been identified in Seattle with a mutation in the same codon (SEPTIN6 c.1282T>A) suggesting an important new molecular mechanism for pediatric MDS. Both identified patients had a high degree of myeloid tetraploidy in the marrow and were refractory to G-CSF. To assess the pathobiology of the published patient's mutation, we replicated the germline T>C mutation using single base-pair gene editing in normal donor primary CD34+ cells. Editing rates were ~50-70%. Morphological studies demonstrated that SEPTIN-6 edited human CD34+ cells demonstrated enlarged, multi-nucleated and dysplastic nuclei. These findings were similar to the appearance of the patient's bone marrow myeloid precursor cells. These edited cells also demonstrated a decline in clonogenic activity notably with a selective reduction in granulocyte-macrophage (GM) colonies (Table 1). Both myeloid and erythroid colonies showed a reduction in colony size. These data directly confirm an important role for this mutated SEPTIN-6 in abnormal hematopoietic function. The septin-6 family of proteins consist of septin-6, 8, 10, 11 and 14 which may have overlapping functions in cells. Murine single cell mRNA expression data demonstrate that hematopoietic stem and progenitor cells (HSPC) express significant levels of Septin-6, Septin-11 and 8, with little to no expression of Septin-10 and 14. To better understand the functional role of Septin-6, we created lentivirus vectors tagged with a GFP reporter that contained shRNAs against Septin-6. Culture of Septin-6 knockdown (Septin-6 KD) murine HSPC in IMDM (10ng/ml IL-3, 25ng/ml of SCF, TPO, Flt-3 and IL-6) resulted in an average of 18-fold decrease in cell counts compared to controls (p=0.02). This was accompanied by an increase in cell cycle: S-phase: Septin-6 KD 55.7%; controls 42.5%, p=0.05 and a cumulative decrease in the G0/G1 and G2/M phase suggesting that Septin-6 is important in regulating cell cycle in HSPC. Controls were a non-targeting shRNA and an empty vector for all experiments described. Furthermore, knockdown of Septin-6 caused a decrease in total clonogenic activity with defects seen in both myeloid (GM) and erythroid (BFU-E) colonies (Table 1). Competitive repopulation assays, wherein transduced BoyJ HSPC (GFP+ Septin KD and BFP+ control were mixed 1:1) were injected into lethally irradiated C57Bl/6 mice, demonstrated a reduction in multilineage chimerism in the peripheral blood, bone marrow, spleen and thymus in primary and secondary transplant recipients after knockdown of Septin-6 (Table 2). To better define function in specific hematopoietic populations of HSPC, we performed knockdown in FACS-sorted purified cells. Engraftment studies demonstrated a significant reduction in bone marrow chimerism in primary transplant recipients after knockdown of Septin-6 most clearly in ST-HSC (Table 2) with a trend towards a decrease in LT-HSC and MPP. These data support a key role of Septin-6 in murine and human hematopoiesis via alterations in cell cycle and validate the pathogenic nature of a specific mutation in human SEPTIN-6. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Predictors of Disease Progression and Survival in Patients with Myelodysplastic Syndrome Secondary to Inherited Bone Marrow Failure Syndromes

Introduction Inherited bone marrow failure syndromes (IBMFSs) are rare genetic disorders characterized by abnormal hematopoiesis resulting in cytopenias, risk of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Once patients develop MDS, the only cure is hematopoietic stem cell transplant (HSCT). Proceeding to HSCT before transformation to advanced MDS or AML leads to better outcomes (Smith et al., PBC 2013). The rate of disease progression from early MDS to advanced MDS or AML is variable and risk factors for progression in IBMFS patients are unknown. We hypothesized that certain variables could predict the likelihood of progression, and that the type of disease progression may impact overall survival (OS). Methods Data were collected from patients prospectively enrolled in the Canadian Inherited Marrow Failure Registry (CIMFR), a Canadian collaboration including >95% of pediatric IBMFS patients. Patients were diagnosed with a specific syndrome or unclassified IBMFS (ucIBMFS) based on published criteria. Diagnostic criteria for pediatric MDS defined by Cada et al. (Haematologica 2015) were used, patients with refractory cytopenia (RC) with or without dysplasia or ringed sideroblasts were included. Patients with refractory cytopenia with excess blasts (RCEB) were excluded. MDS progression was defined as 1 or more of: a new cytogenetic abnormality, more advanced cytopathology, worse cytopenias requiring HSCT. Variables evaluated included: involvement of specific organ systems, hematologic parameters within 3 months of cytogenetic clones/MDS diagnosis, type of mutation (as per Waespe et al., Genomic Medicine 2017). Univariate Cox Proportional Hazard modelling was used to estimate association with specific variables and disease progression, Kaplan-Meier analysis was used for survival evaluation. Results Between January 1, 2001 and November 30, 2018, 601 patients were enrolled in the CIMFR, and during this time 59 (9.8%) developed cytogenetic clones/MDS. Four did not meet the pre-defined criteria for IBMFS, 9 had RCEB at diagnosis with MDS and 1 did not have data available; these were excluded from our cohort of 45 patients. Twelve (26%) patients with clones/MDS had Fanconi Anemia (FA), 13 (28.3%) had Shwachman-Diamond Syndrome (SDS), 5 (10.8%) had ucIBMFS, 15 (33.3%) had other IBMFSs. The most common cytogenetic finding at diagnosis was -7/-7q (n=10, 22%). Patients who developed clones/MDS had significantly worse OS compared to those without clones/MDS (HR 3, 95% CI 2-6, p<0.0001). Among patients who developed clones/MDS, 22 (48.9%) underwent HSCT. Twenty one clones/MDS patients (46.7%) had disease progression, with a median time to progression of 7.9 months (1.2-131.4). The majority (68.4%) developed progression within one year of clones/MDS diagnosis. Nine (42.8%) developed more advanced cytopathology, 9 (42.8%) a new cytogenetic abnormality and 5 (23.8%) worsening cytopenias. Most patients with FA (67%) had disease progression, compared to 38.5% of patients with SDS. Mutation types (classified as more vs less deleterious) were similar between the groups with and without progression. The evaluated hematologic parameters (MCV, hemoglobin, platelets and neutrophils within 3 months of diagnosis) were not predictive of disease progression. Patients with disease progression, when compared to those without, were more likely to have congenital malformations of the skin (14.3% vs 0%), cardiovascular system (28.6% vs 4.2%) and kidneys (14.3% vs 4.2%). No specific system involvement predicted disease progression, although congenital malformations of the cardiovascular system had a HR of 2.63 (95% CI 0.93-7.42). Conclusion Development of MDS has a significant adverse impact on the OS of IBMFS patients, with disease progression typically occurring within the first year after MDS diagnosis. Patients with FA have a high risk of disease progression. Hematologic parameters were not predictive of the risk of disease progression, however, the presence of congenital cardiovascular anomalies is suggestive of increased risk of disease progression and warrants further investigation. Our study is limited by the rare nature of IBMFSs and MDS and the collection of additional data will help to guide treatment decisions for this high-risk patient population. Acknowledgment The authors thank Mr. Bryan Maguire for his statistical analysis of data related to this work.

Myelodysplastic Syndrome with Monosomy 7 in a Patient with Ataxia-Pancytopenia Syndrome

Abstract Introduction/Objective Ataxia-pancytopenia syndrome is caused by mutations in SAMD9L, a tumor suppressor gene on chromosome 7 with roles in normal hematopoiesis and cerebellar development. Syndrome manifestations consist of a combination of progressive ataxia, multilineage cytopenias, and increased risk of myeloid neoplasms associated with monosomy 7. Histopathologic and radiologic descriptions of this recently described disorder are scarce and treatment strategies are not standardized. Additionally, features that predict spontaneous hematologic remission of myeloid neoplasms are incompletely understood. Therefore, detailed discussions of this disorder and its possible outcomes are warranted. Methods/Case Report A six-year-old boy was brought to his doctor when his parents noticed head tilting while reading and impaired coordination. Brain MRI revealed extensive T2/FLAIR hyperintensities of white matter, cerebellar hypoplasia, and a thinned corpus callosum. Further evaluation excluded autoimmune etiologies, infectious diseases, and inherited leukodystrophies. Whole exome sequencing demonstrated a previously uncharacterized heterozygous mutation in SAMD9L, c.2062T&amp;gt;A; p.Tyr688Asn. Subsequent testing revealed pancytopenia. A bone marrow biopsy showed small megakaryocytes with abnormal nuclear lobation and erythroid progenitors with nuclear blebbing and binucleation. Blasts were borderline increased (4%). Fluorescence in-situ hybridization and karyotype showed monosomy 7. A myeloid next-generation sequencing panel identified an ETV6 mutation (p.Gln143Ter, VAF=5.4%). A diagnosis of myelodysplastic syndrome with monosomy 7 in the setting of ataxia-pancytopenia syndrome was rendered. The patient underwent allogeneic stem cell transplant and is doing well at last follow-up. Results (if a Case Study enter NA) N/A Conclusion Ataxia pancytopenia syndrome is a recently described and incompletely understood disorder. Some myeloid neoplasms in ataxia-pancytopenia syndrome can undergo somatic revertant mosaicism via uniparental disomy, resulting in spontaneous hematologic remission. Factors that predict spontaneous remission are unclear; however, secondary mutations have been associated with poorer outcomes. This case emphasizes the value of comprehensive genetic testing modalities in challenging cases. Screening for SAMD9L mutations in cases of pediatric myelodysplastic syndrome could be considered.