evaluated in germline DNA (CD3 + T cells from peripheral blood or hair follicles). Eleven of 38 patients had moderate, 12 severe, and 15 very severe AA. Median age of AA patients at diagnosis was 30 years (range 9-79 years). Three patients (8%) had abnormal cytogenetics ( Online Supplementary Table S1 ). In haematologica 2014; 99:e165 L ETTERS TO THE E DITOR Table 1. Mutations in aplastic anemia patients. Sequence numbering is according to the protein sequence of Ensembl protein ID ENSP00000266058 (SLIT1), ENSP00000282030 (SETBP1) and ENSP00000364839 (ASXL1), ENSP00000217026 (MYBL2), ENSP00000442788 (TET2), of genome build GRCh37, release 73. Characteristic Somatic mutations Germline SNVs Patient ID 1 2 3 4 Age at diagnosis (years) 61 14 42 45 Age at sampling (years) 61 28 58 45 Sex M M F F Severity VSAA SAA MAA SAA Treatment ATG/ ATG/CSA, alloHSCT CSA, ATG/CSA Syngeneic HSCT Time from diagnosis to first treatment (months) 0.5 16 1 4 Best response (CR, PR) CR CR PR CR Time from last treatment to last follow up (years) 1.9 8.3 4.3 9 PNH clone (granulocytes, %) 4 1.4 0 0 Telomere length (average T/S ratio) unknown unknown 1.25 unknown Source of DNA BM PB BM PB Karyotype 46,XY 46,XY 46,XX, 46,XX developed trisomy 8 Affected gene SLIT1 SETBP1, MYBL2 TET2 ASXL1 Variation, nucleotide level c.1252C>A c.2602G>A c.844T>C c.2981A>G c.1934dupG Variation, protein level p.Q418K p.D868N**, p.S282P p.H994R* p.G645fs*** Germline affected No No Yes Yes Variant allele frequency (%) 50 § 35 § 38.7 50 25 § Survival from diagnosis 1.5, alive 21.6, alive 16.8, alive 7.5, alive (years), status M: male; F: female; SAA: severe aplastic anemia;VSAA: very severe aplastic anemia; MAA: moderate aplastic anemia; ATG: anti-thymocyte globulin; CSA: ciclosporin; alloHSCT: allogeneic hematopoietic stem cell transplantation; PB: peripheral blood; BM: bone marrow; n.a.: not applicable. *previously identified as somatic SNV COSM1426210 **pre- viously identified as somatic SNV in SETBP1, COSM1318401 ***previously identified as somatic insertion in ASXL1, COSM34210 § estimated from Sanger sequencing trace.
17 patients (44.7%), a GPI-deficient clone suggesting PNH/AA overlap syndrome was present. Twenty-two patients underwent allogeneic or syngeneic transplanta- tion. The median duration of follow up from diagnosis of patients alive was seven years. Thirty-five of 38 patients were alive at last follow up. In support of the diagnosis of AA, telomeres in peripheral blood leukocytes were signif- icantly shorter in AA patients (n=13) than in age-matched healthy controls (n=20) (median age AA, 44 years; median age healthy controls, 43 years, P =0.43; mean T/S ratio AA patients 1.43, mean T/S ratio healthy controls, 2.48, P <0.001) ( Online Supplementary Figure S1 ). Next generation sequencing yielded an average coverage of 2015 reads per amplicon. In total, 3 somatic mutations were identified in 2 patients in the examined MDS candidate genes (5.3%) (Table 1 and Online Supplementary Figure S2 ). One patient had a somatic missense mutation in SLIT1, and one patient with severe AA had two somatic mutations, one missense mutation in SETPB1 (D868N) and one frameshift mutation in ASXL1 ( G645fs ). This patient was diagnosed with severe AA at the age of 14 years and received four courses of immunosuppressive therapy. After the first cycle of ATG, the patient was in remission for four years.
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- Fall '19
- Mutation, Aplastic Anemia