A total of 192 pediatric patients, median age 8.6 years, with high-risk hematological malignancies, underwent haploidentical stem cell transplantation (haplo-HSCT) using post-transplantation cyclophosphamide (PT-Cy), or ex vivo T cell-depleted (TCD) graft platforms, from January 1999 to December 2016 in 10 centers in Spain. Some 41 patients received an unmanipulated graft followed by PT-Cy for graft-vs-host disease (GvHD) prophylaxis. A total of 151 patients were transplanted with CD3-depleted peripheral blood stem cells (PBSCs) by either CD34 + selection, CD3 + CD19 + depletion, TCRαβ + CD19 + depletion or CD45RA + depletion, added to CD34 + selection for GvHD prophylaxis. The PBSCs were the only source in patients

PurposePatients with Fanconi anaemia (FA), a rare DNA repair genetic disease, exhibit chromosome fragility, bone marrow failure, malformations and cancer susceptibility. FA molecular diagnosis is challenging since FA is caused by point mutations and large deletions in 22 genes following three heritability patterns. To optimise FA patients’ characterisation, we developed a simplified but effective methodology based on whole exome sequencing (WES) and functional studies.Methods68 patients with FA were analysed by commercial WES services. Copy number variations were evaluated by sequencing data analysis with RStudio. To test FANCA missense variants, wt FANCA cDNA was cloned and variants were introduced by site-directed mutagenesis. Vectors were then tested for their ability to complement DNA repair defects of a FANCA-KO human cell line generated by TALEN technologies.ResultsWe identified 93.3% of mutated alleles including large deletions. We determined the pathogenicity of three FANCA missense variants and demonstrated that two FANCA variants reported in mutations databases as ‘affecting functions’ are SNPs. Deep analysis of sequencing data revealed patients’ true mutations, highlighting the importance of functional analysis. In one patient, no pathogenic variant could be identified in any of the 22 known FA genes, and in seven patients, only one deleterious variant could be identified (three patients each with FANCA and FANCD2 and one patient with FANCE mutations)ConclusionWES and proper bioinformatics analysis are sufficient to effectively characterise patients with FA regardless of the rarity of their complementation group, type of mutations, mosaic condition and DNA source.

Agammaglobulinemia is a primary immunodeficiency disorder characterized by profoundly low or absent serum antibodies and low or absent circulating B cells. The most common form is X-linked agammaglobulinemia (XLA) caused by mutations in BTK gene. The remaining cases, clinically similar to XLA, are autosomal recessive agammaglobulinemia (ARA). Nearly 30% of ARA cases present mutations in the μ heavy constant region gene IGHM. Here, we present a 7-month-old patient, born from non-consanguineous parents, who is affected by ARA due to defect in the μ heavy chain. The genetic study showed that the patient is compound heterozygous for an IGHM gene deletion and the novel nonsense mutation X57331.1:g.275C>A (p.Tyr43*) (ClinVar Accession Number: SCV000537868.1). This finding allows for an adequate genetic counseling to the family and also broadens the spectrum of already described point mutations at this locus. The IGHM gene is very complex and it is likely that yet unidentified mutations appear in other patients.

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Background T‐cell lymphoblastic lymphoma (T‐LBL) is an aggressive neoplasm closely related to T‐cell acute lymphoblastic leukaemia (T‐ALL). Despite their similarities, and contrary to T‐ALL, studies on paediatric T‐LBL are scarce and, therefore, its molecular landscape has not yet been fully elucidated. Thus, the aims of this study were to characterize the genetic and molecular heterogeneity of paediatric T‐LBL and to evaluate novel molecular markers differentiating this entity from T‐ALL. Procedure Thirty‐three paediatric T‐LBL patients were analyzed using an integrated approach, including targeted next‐generation sequencing, RNA‐sequencing transcriptome analysis and copy‐number arrays. Results Copy number and mutational analyses allowed the detection of recurrent homozygous deletions of 9p/CDKN2A (78%), trisomy 20 (19%) and gains of 17q24‐q25 (16%), as well as frequent mutations of NOTCH1 (62%), followed by the BCL11B (23%), WT1 (19%) and FBXW7, PHF6 and RPL10 genes (15%, respectively). This genetic profile did not differ from that described in T‐ALL in terms of mutation incidence and global genomic complexity level, but unveiled virtually exclusive 17q25 gains and trisomy 20 in T‐LBL. Additionally, we identified novel gene fusions in paediatric T‐LBL, including NOTCH1–IKZF2, RNGTT–SNAP91 and DDX3X–MLLT10, the last being the only one previously described in T‐ALL. Moreover, clinical correlations highlighted the presence of Notch pathway alterations as a factor related to favourable outcome. Conclusions In summary, the genomic landscape of paediatric T‐LBL is similar to that observed in T‐ALL, and Notch signaling pathway deregulation remains the cornerstone in its pathogenesis, including not only mutations but fusion genes targeting NOTCH1.