Myb-like, SWIRM, and MPN domains 1 (MYSM1) deficiency: Genotoxic stress-associated bone marrow failure and developmental aberrations.

BACKGROUND: Myb-like, SWIRM, and MPN domains 1 (MYSM1) is a transcriptional regulator mediating histone deubiquitination. Its role in human immunity and hematopoiesis is poorly understood. OBJECTIVES: We sought to investigate the clinical, cellular, and molecular features in 2 siblings presenting with progressive bone marrow failure (BMF), immunodeficiency, and developmental aberrations. METHODS: We performed genome-wide homozygosity mapping, whole-exome and Sanger sequencing, immunophenotyping studies, and analysis of genotoxic stress responses. p38 activation, reactive oxygen species levels, rate of apoptosis and clonogenic survival, and growth in immune and nonimmune cells were assessed. The outcome of allogeneic hematopoietic stem cell transplantation (HSCT) was monitored. RESULTS: We report 2 patients with progressive BMF associated with myelodysplastic features, immunodeficiency affecting B cells and neutrophil granulocytes, and complex developmental aberrations, including mild skeletal anomalies, neurocognitive developmental delay, and cataracts. Whole-exome sequencing revealed a homozygous premature stop codon mutation in the gene encoding MYSM1. MYSM1-deficient cells are characterized by increased sensitivity to genotoxic stress associated with sustained induction of phosphorylated p38 protein, increased reactive oxygen species production, and decreased survival following UV light-induced DNA damage. Both patients were successfully treated with allogeneic HSCT with sustained reconstitution of hematopoietic defects. CONCLUSIONS: Here we show that MYSM1 deficiency is associated with developmental aberrations, progressive BMF with myelodysplastic features, and increased susceptibility to genotoxic stress. HSCT represents a curative therapy for patients with MYSM1 deficiency.

Poikiloderma with Neutropenia in Morocco: a Report of Four Cases.

PURPOSE: Poikiloderma with Neutropenia (PN) is inherited genodermatosis which results from a biallelic mutation in the USB1 gene (U Six Biogenesis 1). PN, first described in Navajo Native Americans, is characterized by early onset poikiloderma, pachyonychia, palmo-plantar hyperkeratosis, and permanent neutropenia. This condition results in frequent respiratory tract infections during infancy and childhood. From 2011 to 2013, four cases of PN were diagnosed in Morocco. In this paper, we report the first four cases of PN diagnosed in Morocco, out of three unrelated consanguinous families. METHODS: We investigated the genetic, immunological, and clinical features of four Moroccan patients with PN from three unrelated consanguinous families. RESULTS: Mean age at onset was 3 months and mean age at diagnosis was 7.5 years. The diagnosis of these PN patients was made based on clinical features and confirmed by molecular analysis for three cases. We identified two undescribed homozygous mutations in the USB1 gene: c.609 + 1G>A in two siblings and c.518 T>G(p.(Leu173Arg)) in the other case. CONCLUSION: This report confirms the clinical and genetic identity of Poikiloderma with Neutropenia syndrome.

Inherited biallelic CSF3R mutations in severe congenital neutropenia.

Severe congenital neutropenia (SCN) is characterized by low numbers of peripheral neutrophil granulocytes and a predisposition to life-threatening bacterial infections. We describe a novel genetic SCN type in 2 unrelated families associated with recessively inherited loss-of-function mutations in CSF3R, encoding the granulocyte colony-stimulating factor (G-CSF) receptor. Family A, with 3 affected children, carried a homozygous missense mutation (NM_000760.3:c.922C>T, NP_000751.1:p.Arg308Cys), which resulted in perturbed N-glycosylation and aberrant localization to the cell surface. Family B, with 1 affected infant, carried compound heterozygous deletions provoking frameshifts and premature stop codons (NM_000760.3:c.948_963del, NP_000751.1:p.Gly316fsTer322 and NM_000760.3:c.1245del, NP_000751.1:p.Gly415fsTer432). Despite peripheral SCN, all patients had morphologic evidence of full myeloid cell maturation in bone marrow. None of the patients responded to treatment with recombinant human G-CSF. Our study highlights the genetic and morphologic SCN variability and provides evidence both for functional importance and redundancy of G-CSF receptor-mediated signaling in human granulopoiesis.

Very early onset inflammatory bowel disease associated with aberrant trafficking of IL-10R1 and cure by T cell replete haploidentical bone marrow transplantation.

PURPOSE: Loss-of-function mutations in IL10 and IL10R cause very early onset inflammatory bowel disease (VEO-IBD). Here, we investigated the molecular pathomechanism of a novel intronic IL10RA mutation and describe a new therapeutic approach of T cell replete haploidentical hematopoietic stem cell transplantation (HSCT). METHODS: Clinical data were collected by chart review. Genotypes of IL10 and IL10R genes were determined by Sanger sequencing. Expression and function of mutated IL-10R1 were assessed by quantitative PCR, Western blot analysis, enzyme-linked immunosorbent assays, confocal microscopy, and flow cytometry. RESULTS: We identified a novel homozygous point mutation in intron 3 of the IL10RA (c.368-10C > G) in three related children with VEO-IBD. Bioinformatical analysis predicted an additional 3' splice site created by the mutation. Quantitative PCR analysis showed normal mRNA expression of mutated IL10RA. Sequencing of the patient's cDNA revealed an insertion of the last nine nucleotides of intron 3 as a result of aberrant splicing. Structure-based modeling suggested misfolding of mutated IL-10R1. Western blot analysis demonstrated a different N-linked glycosylation pattern of mutated protein. Immunofluorescence and FACS analysis revealed impaired expression of mutated IL-10R1 at the plasma membrane. In the absence of HLA-identical donors, T cell replete haploidentical HSCT was successfully performed in two patients. CONCLUSIONS: Our findings expand the spectrum of IL10R mutations in VEO-IBD and emphasize the need for genetic diagnosis of mutations in conserved non-coding sequences of candidate genes. Transplantation of haploidentical stem cells represents a curative therapy in IL-10R-deficient patients, but may be complicated by non-engraftment.

Evidence-based interventions for children and adolescents with fetal alcohol spectrum disorders - A systematic review.

INTRODUCTION: Brain function deficits cause strong negative impacts for the everyday lives of children and adolescents with fetal alcohol spectrum disorders (FASD). Therefore, evidence-based intervention programs that are specifically designed for patients with FASD are needed but still scarce. The aim of the presented article is a systematic literature review of evidence-based intervention strategies for children and adolescents with FASD. MATERIALS AND METHODS: A comprehensive systematic literature search was conducted in several relevant databases to identify randomized-controlled intervention studies for children and adolescents with FASD. RESULTS: We identified 25 randomized-controlled studies regarding interventions in FASD. Overall, evidence indicating that some therapeutic interventions are effective in children and adolescents with FASD was found. Even though evidence-based interventions rarely lead to improvements of performance into a "normal range", those measures can alleviate negative consequences of prenatal alcohol exposure and relieve daily burdens. CONCLUSION: There are only a few randomized-controlled trials regarding therapy research for children and adolescents with FASD. Their results indicate that especially the combination of parent and child sessions present a promising approach for the treatment of FASD. Positive treatment effects of interventions seem to be domain specific, except for interventions regarding self-regulation or social interaction.

ABCB1 protects kidney proximal tubule cells against cadmium-induced apoptosis: roles of cadmium and ceramide transport.

Cadmium (Cd(2+)) damages the kidney proximal tubule (PT) by ceramide-dependent apoptosis and is also a class I carcinogen. Multidrug resistance P-glycoprotein (MDR1, ABCB1) confers resistance to Cd(2+) apoptosis, and it has been hypothesized that ABCB1 can directly transport Cd(2+) as a mode of cellular protection. Our aim was to investigate the role of ABCB1 in Cd(2+) transport and ceramide apoptosis. In rat PT or Madin-Darby canine kidney (MDCK) cells overexpressing ABCB1, ABCB1-dependent efflux of rhodamine 123(+) (Rh123(+)) or (109)Cd(2+) were determined, and cell death was assayed with MTT, H-33342 nuclear staining, and monolayer integrity by impedance sensing (Electric cell-substrate impedance sensing [ECIS]). ABCB1 inhibitors (PSC833, UIC-2 antibody) did not affect (109)Cd(2+) efflux in PT cells though Rh123(+) transport was blocked. Furthermore, increased ABCB1 expression did not augment (109)Cd(2+) efflux but attenuated apoptosis by 10-50µM Cd(2+) or 5-25µM C(6)-ceramide, which was abolished by PSC833 (1µM). ECIS measurements of ABCB1-MDCK monolayers exhibited similar effects. Moreover, in ABCB1-MDCK cells, Cd(2+)-induced ceramide formation, determined by a diacylglycerol kinase assay, was abolished and increased extrusion of nitro-2-1,3-benzoxadiazol-4-yl (NBD)-C(6)-ceramide, and NBD-C(6)-glucosylceramide was observed compared with MDCK cells. Whereas pharmacological block of sphingomyelin synthase (0.1mM D609) or sphingosine kinase (1µM dimethylsphingosine), which increase the levels of ceramide and its metabolites, augmented Cd(2+)-induced apoptosis, Cd(2+) apoptosis was significantly decreased not only by prevention of de novo ceramide synthesis (0.1µM fumonisin B(1)) but also by inhibition of glucosylceramide synthase (2µM C(9)DGJ). We therefore conclude that Cd(2+) efflux is not the mechanism behind ABCB1-mediated protection from Cd(2+) apoptosis. Rather, the sphingolipid glucosylceramide may be the proapoptotic substrate extruded by ABCB1.