1. Clinical evolution, genetic landscape and trajectories of clonal hematopoiesis in SAMD9/SAMD9L syndromes
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Sahoo, Sushree S., Pastor, Victor B., Goodings, Charnise, Voss, Rebecca K., Kozyra, Emilia J., Szvetnik, Amina, and Noellke, Peter
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Gene mutations -- Analysis ,Cell death -- Observations -- Health aspects ,Hematopoiesis -- Analysis ,Myelodysplastic syndromes -- Diagnosis -- Care and treatment -- Development and progression ,Biological sciences ,Health - Abstract
Germline SAMD9 and SAMD9L mutations (SAMD9/9L.sup.mut) predispose to myelodysplastic syndromes (MDS) with propensity for somatic rescue. In this study, we investigated a clinically annotated pediatric MDS cohort (n = 669) to define the prevalence, genetic landscape, phenotype, therapy outcome and clonal architecture of SAMD9/9L syndromes. In consecutively diagnosed MDS, germline SAMD9/9L.sup.mut accounted for 8% and were mutually exclusive with GATA2 mutations present in 7% of the cohort. Among SAMD9/9L.sup.mut cases, refractory cytopenia was the most prevalent MDS subtype (90%); acquired monosomy 7 was present in 38%; constitutional abnormalities were noted in 57%; and immune dysfunction was present in 28%. The clinical outcome was independent of germline mutations. In total, 67 patients had 58 distinct germline SAMD9/9L.sup.mut clustering to protein middle regions. Despite inconclusive in silico prediction, 94% of SAMD9/9L.sup.mut suppressed HEK293 cell growth, and mutations expressed in CD34.sup.+ cells induced overt cell death. Furthermore, we found that 61% of SAMD9/9L.sup.mut patients underwent somatic genetic rescue (SGR) resulting in clonal hematopoiesis, of which 95% was maladaptive (monosomy 7 [plus or minus] cancer mutations), and 51% had adaptive nature (revertant UPD7q, somatic SAMD9/9L.sup.mut). Finally, bone marrow single-cell DNA sequencing revealed multiple competing SGR events in individual patients. Our findings demonstrate that SGR is common in SAMD9/9L.sup.mut MDS and exemplify the exceptional plasticity of hematopoiesis in children. This analysis of a large, clinically annotated cohort of individuals with predisposition to myelodysplastic syndromes reveals insights into the genetic determinants of disease progression and their relationship with clinical manifestations and therapy outcome., Author(s): Sushree S. Sahoo [sup.1] [sup.2] , Victor B. Pastor [sup.2] , Charnise Goodings [sup.1] , Rebecca K. Voss [sup.2] , Emilia J. Kozyra [sup.2] [sup.3] , Amina Szvetnik [sup.2] [...]
- Published
- 2021
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