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The DNA ligase IV syndrome is a rare hereditary disorder associated with impaired DNA double-strand break repair mechanisms, associated with combined immunodeficiency. We investigated a 12-year old patient with obvious syndromic features, severe microcephaly, short stature, low body weight and bird-like facial features, resembling Seckel syndrome or Fanconi anemia with no signs of acute illness or malignancy.Diagnostic investigation included flow cytometry immunophenotyping and a custom HaloPlexHS (Agilent) NGS panel, to investigate mutations in genes involved in Bone Marrow Failure/Severe Combined Neutropenia, Anemias and Chromosome Breakage Syndrome. Sanger sequencing was performed to determine parental carrier status.Two variants in the LIG4 gene were identified, c.2440C > T (p.Arg814Ter) and c.1273_1278delAGAGAA (p.Arg425_Glu426del). LIG4 c.2440C > T is a nonsense heterozygous variant which prematurely terminates the protein, classified as pathogenic, and LIG4 c.1273_1278del is an in-frame deletion, classified as of uncertain significance according to ACMG recommendations. Compound heterozygous mutations in the LIG4 gene have been associated to DNA ligase IV syndrome, an autosomal recessive disorder caused by homozygous or compound heterozygous mutations. Parental testing revealed that LIG4 c.2440C > T variant was maternally inherited and the LIG4 c.1273_1278delAGAGAA variant was paternally inherited.Globally, approximately forty cases appear in literature, with patients portraying great phenotypic heterogeneity. With a prevalence of

Chronic lymphocytic leukemia (CLL) is characterized by the existence of subsets of patients with (quasi)identical, stereotyped B-cell receptor (BcR) immunoglobulins. Patients in certain major stereotyped subsets often display remarkably consistent clinicobiological profiles, suggesting that the study of BcR immunoglobulin stereotypy in CLL has important implications for understanding disease pathophysiology and refining clinical decision-making. Nevertheless, several issues remain open, especially pertaining to the actual frequency of BcR immunoglobulin stereotypy and major subsets, as well as the existence of higher-order connections between individual subsets. To address these issues, we investigated clonotypic IGHV-IGHD-IGHJ gene rearrangements in a series of 29 856 patients with CLL, by far the largest series worldwide. We report that the stereotyped fraction of CLL peaks at 41% of the entire cohort and that all 19 previously identified major subsets retained their relative size and ranking, while 10 new ones emerged; overall, major stereotyped subsets had a cumulative frequency of 13.5%. Higher-level relationships were evident between subsets, particularly for major stereotyped subsets with unmutated IGHV genes (U-CLL), for which close relations with other subsets, termed "satellites," were identified. Satellite subsets accounted for 3% of the entire cohort. These results confirm our previous notion that major subsets can be robustly identified and are consistent in relative size, hence representing distinct disease variants amenable to compartmentalized research with the potential of overcoming the pronounced heterogeneity of CLL. Furthermore, the existence of satellite subsets reveals a novel aspect of repertoire restriction with implications for refined molecular classification of CLL., (© 2021 by The American Society of Hematology.)

The diagnosis of hematologic malignancies relies on multidisciplinary workflows involving morphology, flow cytometry, cytogenetic, and molecular genetic analyses. Advances in cancer genomics have identified numerous recurrent mutations with clear prognostic and/or therapeutic significance to different cancers. In myeloid malignancies, there is a clinical imperative to test for such mutations in mainstream diagnosis; however, progress toward this has been slow and piecemeal. Here we describe Karyogene, an integrated targeted resequencing/analytical platform that detects nucleotide substitutions, insertions/deletions, chromosomal translocations, copy number abnormalities, and zygosity changes in a single assay. We validate the approach against 62 acute myeloid leukemia, 50 myelodysplastic syndrome, and 40 blood DNA samples from individuals without evidence of clonal blood disorders. We demonstrate robust detection of sequence changes in 49 genes, including difficult-to-detect mutations such as FLT3 internal-tandem and mixed-lineage leukemia (MLL) partial-tandem duplications, and clinically significant chromosomal rearrangements including MLL translocations to known and unknown partners, identifying the novel fusion gene MLL-DIAPH2 in the process. Additionally, we identify most significant chromosomal gains and losses, and several copy neutral loss-of-heterozygosity mutations at a genome-wide level, including previously unreported changes such as homozygosity for DNMT3A R882 mutations. Karyogene represents a dependable genomic diagnosis platform for translational research and for the clinical management of myeloid malignancies, which can be readily adapted for use in other cancers., (© 2016 by The American Society of Hematology.)