Publications by authors named "Asbjorg Stray-Pedersen"

60 Publications

Performance of Expanded Newborn Screening in Norway Supported by Post-Analytical Bioinformatics Tools and Rapid Second-Tier DNA Analyses.

Int J Neonatal Screen 2020 Sep 27;6(3):51. Epub 2020 Jun 27.

Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.).

In 2012, the Norwegian newborn screening program (NBS) was expanded (eNBS) from screening for two diseases to that for 23 diseases (20 inborn errors of metabolism, IEMs) and again in 2018, to include a total of 25 conditions (21 IEMs). Between 1 March 2012 and 29 February 2020, 461,369 newborns were screened for 20 IEMs in addition to phenylketonuria (PKU). Excluding PKU, there were 75 true-positive (TP) (1:6151) and 107 (1:4311) false-positive IEM cases. Twenty-one percent of the TP cases were symptomatic at the time of the NBS results, but in two-thirds, the screening result directed the exact diagnosis. Eighty-two percent of the TP cases had good health outcomes, evaluated in 2020. The yearly positive predictive value was increased from 26% to 54% by the use of the Region 4 Stork post-analytical interpretive tool (R4S)/Collaborative Laboratory Integrated Reports 2.0 (CLIR), second-tier biochemical testing and genetic confirmation using DNA extracted from the original dried blood spots. The incidence of IEMs increased by 46% after eNBS was introduced, predominantly due to the finding of attenuated phenotypes. The next step is defining which newborns would truly benefit from screening at the milder end of the disease spectrum. This will require coordinated international collaboration, including proper case definitions and outcome studies.
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http://dx.doi.org/10.3390/ijns6030051DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7570219PMC
September 2020

Human NK cell deficiency as a result of biallelic mutations in MCM10.

J Clin Invest 2020 10;130(10):5272-5286

Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, New York, USA.

Human natural killer cell deficiency (NKD) arises from inborn errors of immunity that lead to impaired NK cell development, function, or both. Through the understanding of the biological perturbations in individuals with NKD, requirements for the generation of terminally mature functional innate effector cells can be elucidated. Here, we report a cause of NKD resulting from compound heterozygous mutations in minichromosomal maintenance complex member 10 (MCM10) that impaired NK cell maturation in a child with fatal susceptibility to CMV. MCM10 has not been previously associated with monogenic disease and plays a critical role in the activation and function of the eukaryotic DNA replisome. Through evaluation of patient primary fibroblasts, modeling patient mutations in fibroblast cell lines, and MCM10 knockdown in human NK cell lines, we have shown that loss of MCM10 function leads to impaired cell cycle progression and induction of DNA damage-response pathways. By modeling MCM10 deficiency in primary NK cell precursors, including patient-derived induced pluripotent stem cells, we further demonstrated that MCM10 is required for NK cell terminal maturation and acquisition of immunological system function. Together, these data define MCM10 as an NKD gene and provide biological insight into the requirement for the DNA replisome in human NK cell maturation and function.
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http://dx.doi.org/10.1172/JCI134966DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7524476PMC
October 2020

Second-Tier Next Generation Sequencing Integrated in Nationwide Newborn Screening Provides Rapid Molecular Diagnostics of Severe Combined Immunodeficiency.

Front Immunol 2020 9;11:1417. Epub 2020 Jul 9.

Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway.

Severe combined immunodeficiency (SCID) and other T cell lymphopenias can be detected during newborn screening (NBS) by measuring T cell receptor excision circles (TRECs) in dried blood spot (DBS) DNA. Second tier next generation sequencing (NGS) with an amplicon based targeted gene panel using the same DBS DNA was introduced as part of our prospective pilot research project in 2015. With parental consent, 21 000 newborns were TREC-tested in the pilot. Three newborns were identified with SCID, and disease-causing variants in , and were confirmed by NGS on the initial DBS DNA. The molecular findings directed follow-up and therapy: the -SCID underwent early hematopoietic stem cell transplantation (HSCT) without any complications; the leaky SCID received prophylactic antibiotics, antifungals, and immunoglobulin infusions, and underwent HSCT at 1 year of age. The child with -SCID had complete Hirschsprung disease and died at 1 month of age. Since January 2018, all newborns in Norway have been offered NBS for SCID using 1st tier TRECs and 2nd tier gene panel NGS on DBS DNA. During the first 20 months of nationwide SCID screening an additional 88 000 newborns were TREC tested, and four new SCID cases were identified. Disease-causing variants in , and were molecularly confirmed on day 8, 15, 8 and 6, respectively after birth, using the initial NBS blood spot. Targeted gene panel NGS integrated into the NBS algorithm rapidly delineated the specific molecular diagnoses and provided information useful for management, targeted therapy and follow-up i.e., X rays and CT scans were avoided in the radiosensitive SCID. Second tier targeted NGS on the same DBS DNA as the TREC test provided instant confirmation or exclusion of SCID, and made it possible to use a less stringent TREC cut-off value. This allowed for the detection of leaky SCIDs, and simultaneously reduced the number of control samples, recalls and false positives. Mothers were instructed to stop breastfeeding until maternal (CMV) status was determined. Our limited data suggest that shorter time-interval from birth to intervention, may prevent breast milk transmitted CMV infection in classical SCID.
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http://dx.doi.org/10.3389/fimmu.2020.01417DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7381310PMC
April 2021

Disease-associated CTNNBL1 mutation impairs somatic hypermutation by decreasing nuclear AID.

J Clin Invest 2020 08;130(8):4411-4422

Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, USA.

Patients with common variable immunodeficiency associated with autoimmune cytopenia (CVID+AIC) generate few isotype-switched B cells with severely decreased frequencies of somatic hypermutations (SHMs), but their underlying molecular defects remain poorly characterized. We identified a CVID+AIC patient who displays a rare homozygous missense M466V mutation in β-catenin-like protein 1 (CTNNBL1). Because CTNNBL1 binds activation-induced cytidine deaminase (AID) that catalyzes SHM, we tested AID interactions with the CTNNBL1 M466V variant. We found that the M466V mutation interfered with the association of CTNNBL1 with AID, resulting in decreased AID in the nuclei of patient EBV-transformed B cell lines and of CTNNBL1 466V/V Ramos B cells engineered to express only CTNNBL1 M466V using CRISPR/Cas9 technology. As a consequence, the scarce IgG+ memory B cells from the CTNNBL1 466V/V patient showed a low SHM frequency that averaged 6.7 mutations compared with about 18 mutations per clone in healthy-donor counterparts. In addition, CTNNBL1 466V/V Ramos B cells displayed a decreased incidence of SHM that was reduced by half compared with parental WT Ramos B cells, demonstrating that the CTNNBL1 M466V mutation is responsible for defective SHM induction. We conclude that CTNNBL1 plays an important role in regulating AID-dependent antibody diversification in humans.
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http://dx.doi.org/10.1172/JCI131297DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7410074PMC
August 2020

Delayed Radiation Myelopathy in a Child With Hodgkin Lymphoma and ARTEMIS Mutation.

J Pediatr Hematol Oncol 2021 Apr;43(3):e404-e407

Departments of Pediatric Hematology and Oncology.

The authors present a case of delayed radiation myelopathy in a 12-year-old girl with Hodgkin lymphoma and Artemis mutation. This is the first of such a case presented in the literature.
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http://dx.doi.org/10.1097/MPH.0000000000001815DOI Listing
April 2021

Nordic Guidelines for Germline Predisposition to Myeloid Neoplasms in Adults: Recommendations for Genetic Diagnosis, Clinical Management and Follow-up.

Hemasphere 2019 12 4;3(6):e321. Epub 2019 Nov 4.

Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Denmark.

Myeloid neoplasms (MNs) with germline predisposition have recently been recognized as novel entities in the latest World Health Organization (WHO) classification for MNs. Individuals with MNs due to germline predisposition exhibit increased risk for the development of MNs, mainly acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Setting the diagnosis of MN with germline predisposition is of crucial clinical significance since it may tailor therapy, dictate the selection of donor for allogeneic hematopoietic stem cell transplantation (allo-HSCT), determine the conditioning regimen, enable relevant prophylactic measures and early intervention or contribute to avoid unnecessary or even harmful medication. Finally, it allows for genetic counseling and follow-up of at-risk family members. Identification of these patients in the clinical setting is challenging, as there is no consensus due to lack of evidence regarding the criteria defining the patients who should be tested for these conditions. In addition, even in cases with a strong suspicion of a MN with germline predisposition, no standard diagnostic algorithm is available. We present the first version of the Nordic recommendations for diagnostics, surveillance and management including considerations for allo-HSCT for patients and carriers of a germline mutation predisposing to the development of MNs.
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http://dx.doi.org/10.1097/HS9.0000000000000321DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6924562PMC
December 2019

Infliximab therapy for inflammatory colitis in an infant with NEMO deficiency.

Immunol Res 2019 10;67(4-5):450-453

Center for Human Immunobiology-Immunology-Allergy-Rhematology, Texas Children Hospital-Baylor College of Medicine, Houston, TX, USA.

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http://dx.doi.org/10.1007/s12026-019-09100-zDOI Listing
October 2019

A novel disorder involving dyshematopoiesis, inflammation, and HLH due to aberrant CDC42 function.

J Exp Med 2019 12 10;216(12):2778-2799. Epub 2019 Oct 10.

Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy

Hemophagocytic lymphohistiocytosis (HLH) is characterized by immune dysregulation due to inadequate restraint of overactivated immune cells and is associated with a variable clinical spectrum having overlap with more common pathophysiologies. HLH is difficult to diagnose and can be part of inflammatory syndromes. Here, we identify a novel hematological/autoinflammatory condition (NOCARH syndrome) in four unrelated patients with superimposable features, including neonatal-onset cytopenia with dyshematopoiesis, autoinflammation, rash, and HLH. Patients shared the same de novo mutation (Chr1:22417990C>T, p.R186C) and altered hematopoietic compartment, immune dysregulation, and inflammation. mutations had been associated with syndromic neurodevelopmental disorders. In vitro and in vivo assays documented unique effects of p.R186C on CDC42 localization and function, correlating with the distinctiveness of the trait. Emapalumab was critical to the survival of one patient, who underwent successful bone marrow transplantation. Early recognition of the disorder and establishment of treatment followed by bone marrow transplant are important to survival.
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http://dx.doi.org/10.1084/jem.20190147DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6888978PMC
December 2019

Mutations in PIGU Impair the Function of the GPI Transamidase Complex, Causing Severe Intellectual Disability, Epilepsy, and Brain Anomalies.

Am J Hum Genet 2019 08 25;105(2):395-402. Epub 2019 Jul 25.

Institute for Genomic Statistics and Bioinformatics, University Hospital Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, 53127 Bonn, Germany.

The glycosylphosphatidylinositol (GPI) anchor links over 150 proteins to the cell surface and is present on every cell type. Many of these proteins play crucial roles in neuronal development and function. Mutations in 18 of the 29 genes implicated in the biosynthesis of the GPI anchor have been identified as the cause of GPI biosynthesis deficiencies (GPIBDs) in humans. GPIBDs are associated with intellectual disability and seizures as their cardinal features. An essential component of the GPI transamidase complex is PIGU, along with PIGK, PIGS, PIGT, and GPAA1, all of which link GPI-anchored proteins (GPI-APs) onto the GPI anchor in the endoplasmic reticulum (ER). Here, we report two homozygous missense mutations (c.209T>A [p.Ile70Lys] and c.1149C>A [p.Asn383Lys]) in five individuals from three unrelated families. All individuals presented with global developmental delay, severe-to-profound intellectual disability, muscular hypotonia, seizures, brain anomalies, scoliosis, and mild facial dysmorphism. Using multicolor flow cytometry, we determined a characteristic profile for GPI transamidase deficiency. On granulocytes this profile consisted of reduced cell-surface expression of fluorescein-labeled proaerolysin (FLAER), CD16, and CD24, but not of CD55 and CD59; additionally, B cells showed an increased expression of free GPI anchors determined by T5 antibody. Moreover, computer-assisted facial analysis of different GPIBDs revealed a characteristic facial gestalt shared among individuals with mutations in PIGU and GPAA1. Our findings improve our understanding of the role of the GPI transamidase complex in the development of nervous and skeletal systems and expand the clinical spectrum of disorders belonging to the group of inherited GPI-anchor deficiencies.
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http://dx.doi.org/10.1016/j.ajhg.2019.06.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6698879PMC
August 2019

Allogeneic hematopoietic stem cell transplant outcomes for patients with dominant negative IKZF1/IKAROS mutations.

J Allergy Clin Immunol 2019 07 6;144(1):339-342. Epub 2019 Apr 6.

Division of Bone Marrow Transplantation and Immune Deficiency, Cincinnati Children's Hospital Medical Center and University of Cincinnati, Cincinnati, Ohio.

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http://dx.doi.org/10.1016/j.jaci.2019.03.025DOI Listing
July 2019

Missense Variants in the Histone Acetyltransferase Complex Component Gene TRRAP Cause Autism and Syndromic Intellectual Disability.

Authors:
Benjamin Cogné Sophie Ehresmann Eliane Beauregard-Lacroix Justine Rousseau Thomas Besnard Thomas Garcia Slavé Petrovski Shiri Avni Kirsty McWalter Patrick R Blackburn Stephan J Sanders Kévin Uguen Jacqueline Harris Julie S Cohen Moira Blyth Anna Lehman Jonathan Berg Mindy H Li Usha Kini Shelagh Joss Charlotte von der Lippe Christopher T Gordon Jennifer B Humberson Laurie Robak Daryl A Scott Vernon R Sutton Cara M Skraban Jennifer J Johnston Annapurna Poduri Magnus Nordenskjöld Vandana Shashi Erica H Gerkes Ernie M H F Bongers Christian Gilissen Yuri A Zarate Malin Kvarnung Kevin P Lally Peggy A Kulch Brina Daniels Andres Hernandez-Garcia Nicholas Stong Julie McGaughran Kyle Retterer Kristian Tveten Jennifer Sullivan Madeleine R Geisheker Asbjorg Stray-Pedersen Jennifer M Tarpinian Eric W Klee Julie C Sapp Jacob Zyskind Øystein L Holla Emma Bedoukian Francesca Filippini Anne Guimier Arnaud Picard Øyvind L Busk Jaya Punetha Rolph Pfundt Anna Lindstrand Ann Nordgren Fayth Kalb Megha Desai Ashley Harmon Ebanks Shalini N Jhangiani Tammie Dewan Zeynep H Coban Akdemir Aida Telegrafi Elaine H Zackai Amber Begtrup Xiaofei Song Annick Toutain Ingrid M Wentzensen Sylvie Odent Dominique Bonneau Xénia Latypova Wallid Deb Sylvia Redon Frédéric Bilan Marine Legendre Caitlin Troyer Kerri Whitlock Oana Caluseriu Marine I Murphree Pavel N Pichurin Katherine Agre Ralitza Gavrilova Tuula Rinne Meredith Park Catherine Shain Erin L Heinzen Rui Xiao Jeanne Amiel Stanislas Lyonnet Bertrand Isidor Leslie G Biesecker Dan Lowenstein Jennifer E Posey Anne-Sophie Denommé-Pichon Claude Férec Xiang-Jiao Yang Jill A Rosenfeld Brigitte Gilbert-Dussardier Séverine Audebert-Bellanger Richard Redon Holly A F Stessman Christoffer Nellaker Yaping Yang James R Lupski David B Goldstein Evan E Eichler Francois Bolduc Stéphane Bézieau Sébastien Küry Philippe M Campeau

Am J Hum Genet 2019 03 28;104(3):530-541. Epub 2019 Feb 28.

Centre Hospitalier Universitaire Sainte-Justine Research Centre, University of Montreal, Montreal, QC H3T 1C5, Canada; Department of Pediatrics, University of Montreal, Montreal, QC H3T1J4, Canada. Electronic address:

Acetylation of the lysine residues in histones and other DNA-binding proteins plays a major role in regulation of eukaryotic gene expression. This process is controlled by histone acetyltransferases (HATs/KATs) found in multiprotein complexes that are recruited to chromatin by the scaffolding subunit transformation/transcription domain-associated protein (TRRAP). TRRAP is evolutionarily conserved and is among the top five genes intolerant to missense variation. Through an international collaboration, 17 distinct de novo or apparently de novo variants were identified in TRRAP in 24 individuals. A strong genotype-phenotype correlation was observed with two distinct clinical spectra. The first is a complex, multi-systemic syndrome associated with various malformations of the brain, heart, kidneys, and genitourinary system and characterized by a wide range of intellectual functioning; a number of affected individuals have intellectual disability (ID) and markedly impaired basic life functions. Individuals with this phenotype had missense variants clustering around the c.3127G>A p.(Ala1043Thr) variant identified in five individuals. The second spectrum manifested with autism spectrum disorder (ASD) and/or ID and epilepsy. Facial dysmorphism was seen in both groups and included upslanted palpebral fissures, epicanthus, telecanthus, a wide nasal bridge and ridge, a broad and smooth philtrum, and a thin upper lip. RNA sequencing analysis of skin fibroblasts derived from affected individuals skin fibroblasts showed significant changes in the expression of several genes implicated in neuronal function and ion transport. Thus, we describe here the clinical spectrum associated with TRRAP pathogenic missense variants, and we suggest a genotype-phenotype correlation useful for clinical evaluation of the pathogenicity of the variants.
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http://dx.doi.org/10.1016/j.ajhg.2019.01.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6407527PMC
March 2019

A combined immunodeficiency with severe infections, inflammation, and allergy caused by ARPC1B deficiency.

J Allergy Clin Immunol 2019 06 13;143(6):2296-2299. Epub 2019 Feb 13.

Department of Pediatric Immunology, Rheumatology and Infectious Diseases, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands; Department of Blood Cell Research, Sanquin Research and Landsteiner Laboratory AMC, University of Amsterdam, Amsterdam, the Netherlands. Electronic address:

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http://dx.doi.org/10.1016/j.jaci.2019.02.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6677392PMC
June 2019

De novo variants in FBXO11 cause a syndromic form of intellectual disability with behavioral problems and dysmorphisms.

Eur J Hum Genet 2019 05 24;27(5):738-746. Epub 2019 Jan 24.

Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.

Determining pathogenicity of genomic variation identified by next-generation sequencing techniques can be supported by recurrent disruptive variants in the same gene in phenotypically similar individuals. However, interpretation of novel variants in a specific gene in individuals with mild-moderate intellectual disability (ID) without recognizable syndromic features can be challenging and reverse phenotyping is often required. We describe 24 individuals with a de novo disease-causing variant in, or partial deletion of, the F-box only protein 11 gene (FBXO11, also known as VIT1 and PRMT9). FBXO11 is part of the SCF (SKP1-cullin-F-box) complex, a multi-protein E3 ubiquitin-ligase complex catalyzing the ubiquitination of proteins destined for proteasomal degradation. Twenty-two variants were identified by next-generation sequencing, comprising 2 in-frame deletions, 11 missense variants, 1 canonical splice site variant, and 8 nonsense or frameshift variants leading to a truncated protein or degraded transcript. The remaining two variants were identified by array-comparative genomic hybridization and consisted of a partial deletion of FBXO11. All individuals had borderline to severe ID and behavioral problems (autism spectrum disorder, attention-deficit/hyperactivity disorder, anxiety, aggression) were observed in most of them. The most relevant common facial features included a thin upper lip and a broad prominent space between the paramedian peaks of the upper lip. Other features were hypotonia and hyperlaxity of the joints. We show that de novo variants in FBXO11 cause a syndromic form of ID. The current series show the power of reverse phenotyping in the interpretation of novel genetic variances in individuals who initially did not appear to have a clear recognizable phenotype.
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http://dx.doi.org/10.1038/s41431-018-0292-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6462006PMC
May 2019

Clinical exome sequencing reveals locus heterogeneity and phenotypic variability of cohesinopathies.

Genet Med 2019 03 30;21(3):663-675. Epub 2018 Aug 30.

Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA.

Purpose: Defects in the cohesin pathway are associated with cohesinopathies, notably Cornelia de Lange syndrome (CdLS). We aimed to delineate pathogenic variants in known and candidate cohesinopathy genes from a clinical exome perspective.

Methods: We retrospectively studied patients referred for clinical exome sequencing (CES, N = 10,698). Patients with causative variants in novel or recently described cohesinopathy genes were enrolled for phenotypic characterization.

Results: Pathogenic or likely pathogenic single-nucleotide and insertion/deletion variants (SNVs/indels) were identified in established disease genes including NIPBL (N = 5), SMC1A (N = 14), SMC3 (N = 4), RAD21 (N = 2), and HDAC8 (N = 8). The phenotypes in this genetically defined cohort skew towards the mild end of CdLS spectrum as compared with phenotype-driven cohorts. Candidate or recently reported cohesinopathy genes were supported by de novo SNVs/indels in STAG1 (N = 3), STAG2 (N = 5), PDS5A (N = 1), and WAPL (N = 1), and one inherited SNV in PDS5A. We also identified copy-number deletions affecting STAG1 (two de novo, one of unknown inheritance) and STAG2 (one of unknown inheritance). Patients with STAG1 and STAG2 variants presented with overlapping features yet without characteristic facial features of CdLS.

Conclusion: CES effectively identified disease-causing alleles at the mild end of the cohensinopathy spectrum and enabled characterization of candidate disease genes.
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http://dx.doi.org/10.1038/s41436-018-0085-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6395558PMC
March 2019

Runaway Train: A Leaky Radiosensitive SCID with Skin Lesions and Multiple Lymphomas.

Case Reports Immunol 2018 14;2018:2053716. Epub 2018 May 14.

Department of Hematology, Oslo University Hospital, Oslo, Norway.

The nuclease Artemis is essential for the development of T-cell and B-cell receptors and repair of DNA double-strand breaks, and a loss of expression or function will lead to a radiosensitive severe combined immunodeficiency with no functional T-cells or B-cells (T-B-SCID). Hypomorphic mutations in the gene can lead to a functional, but reduced, T-cell and B-cell repertoire with a more indolent clinical course called "leaky" SCID. Here, we present the case of a young man who had increasingly aggressive lymphoproliferative skin lesions from 2 years of age which developed into multiple EBV+ B-cell lymphomas, where a hypomorphic mutation in the gene was found in a diagnostic race against time using whole exome sequencing. The patient was given a haploidentical stem cell transplant while in remission for his lymphomas and although the initial course was successful, he succumbed to a serious pneumonia 5 months after the transplant. The case underscores the importance of next-generation sequencing in the diagnosis of patients with suspected severe immunodeficiency.
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http://dx.doi.org/10.1155/2018/2053716DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5977007PMC
May 2018

Dystonia-deafness syndrome caused by ACTB p.Arg183Trp heterozygosity shows striatal dopaminergic dysfunction and response to pallidal stimulation.

J Neurodev Disord 2018 05 22;10(1):17. Epub 2018 May 22.

Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.

Background: Dystonia-deafness syndrome is a well-known clinical entity, with sensorineural deafness typically manifesting earlier than dystonia. ACTB p.Arg183Trp heterozygosity has been reported in six patients to cause combined infant-onset deafness and dystonia manifesting in adolescence or young adulthood. Three of these have received beneficial pallidal stimulation. Brain imaging to assess striatal function has not been reported previously, however. Nor has a comprehensive hypothesis been presented for how the pleiotropic manifestations of this specific beta-actin gene mutation originate developmentally.

Case Presentation: A 19-year-old girl with congenital mild dysmorphic facial features, cochlear implants for infant-onset deafness, and mild cognitive and emotional disability, presented with an adolescent-onset, severe generalized dystonia. Brain MRI and multiple single gene sequencing were inconclusive. Due to life-threatening dystonia, we implanted a neurostimulation device, targeting the postero-ventral internal pallidum bilaterally. The Burke-Fahn-Marsden Dystonia Rating Scale motor/disability scores improved from 87/25 to 21/13 at 2.5 months postoperatively, 26/14 at 3 years, and 30/14 at 4 years. Subsequent whole exome sequencing identified heterozygosity for the ACTB p.Arg183Trp variant. Brain imaging included I-ioflupane single photon emission computed tomography (Dopamine Transporter-SPECT), SPECT with I-epidepride (binds to dopamine type 2-receptors) and Fluoro-Deoxy-Glucose (FDG)-PET. Both Epidepride-SPECT and FDG-PET showed reduced tracer uptake in the striatum bilaterally, particularly in the putamen. DaT-SPECT was slightly abnormal.

Conclusions: In this patient with dystonia-deafness syndrome caused by ACTB p.Arg183Trp heterozygosity, unprecedented brain imaging findings strongly indicate striatal neuronal/dopaminergic dysfunction as the underlying cause of the dystonia. Pallidal stimulation provided a substantial improvement of the severe generalized dystonia, which is largely sustained at 4-year follow-up, and we advise this treatment to be considered in such patients. We hypothesize that the pleiotropic manifestations of the dystonia-deafness syndrome caused by this mutation derive from diverse developmental functions of beta-actin in neural crest migration and proliferation (facial dysmorphogenesis), hair cell stereocilia function (infant-onset deafness), and altered synaptic activity patterns associated with pubertal changes in striatal function (adolescent-onset dystonia). The temporal differences in developmental onset are likely due to varying degrees of susceptibility and of compensatory upregulation of other actin variants in the affected structures.
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http://dx.doi.org/10.1186/s11689-018-9235-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5964724PMC
May 2018

A novel NAA10 variant with impaired acetyltransferase activity causes developmental delay, intellectual disability, and hypertrophic cardiomyopathy.

Eur J Hum Genet 2018 09 10;26(9):1294-1305. Epub 2018 May 10.

Department of Biological Sciences, University of Bergen, 5020, Bergen, Norway.

The NAA10-NAA15 complex (NatA) is an N-terminal acetyltransferase that catalyzes N-terminal acetylation of ~40% of all human proteins. N-terminal acetylation has several different roles in the cell, including altering protein stability and degradation, protein localization and protein-protein interactions. In recent years several X-linked NAA10 variants have been associated with genetic disorders. We have identified a previously undescribed NAA10 c.215T>C p.(Ile72Thr) variant in three boys from two unrelated families with a milder phenotypic spectrum in comparison to most of the previously described patients with NAA10 variants. These boys have development delay, intellectual disability, and cardiac abnormalities as overlapping phenotypes. Functional studies reveal that NAA10 Ile72Thr is destabilized, while binding to NAA15 most likely is intact. Surprisingly, the NatA activity of NAA10 Ile72Thr appears normal while its monomeric activity is decreased. This study further broadens the phenotypic spectrum associated with NAA10 deficiency, and adds to the evidence that genotype-phenotype correlations for NAA10 variants are much more complex than initially anticipated.
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http://dx.doi.org/10.1038/s41431-018-0136-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6117304PMC
September 2018

Truncating Variants in NAA15 Are Associated with Variable Levels of Intellectual Disability, Autism Spectrum Disorder, and Congenital Anomalies.

Am J Hum Genet 2018 05 12;102(5):985-994. Epub 2018 Apr 12.

Stanley Institute for Cognitive Genomics, 1Bungtown Road, Cold Spring Harbor Laboratory, NY 11724, USA. Electronic address:

N-alpha-acetylation is a common co-translational protein modification that is essential for normal cell function in humans. We previously identified the genetic basis of an X-linked infantile lethal Mendelian disorder involving a c.109T>C (p.Ser37Pro) missense variant in NAA10, which encodes the catalytic subunit of the N-terminal acetyltransferase A (NatA) complex. The auxiliary subunit of the NatA complex, NAA15, is the dimeric binding partner for NAA10. Through a genotype-first approach with whole-exome or genome sequencing (WES/WGS) and targeted sequencing analysis, we identified and phenotypically characterized 38 individuals from 33 unrelated families with 25 different de novo or inherited, dominantly acting likely gene disrupting (LGD) variants in NAA15. Clinical features of affected individuals with LGD variants in NAA15 include variable levels of intellectual disability, delayed speech and motor milestones, and autism spectrum disorder. Additionally, mild craniofacial dysmorphology, congenital cardiac anomalies, and seizures are present in some subjects. RNA analysis in cell lines from two individuals showed degradation of the transcripts with LGD variants, probably as a result of nonsense-mediated decay. Functional assays in yeast confirmed a deleterious effect for two of the LGD variants in NAA15. Further supporting a mechanism of haploinsufficiency, individuals with copy-number variant (CNV) deletions involving NAA15 and surrounding genes can present with mild intellectual disability, mild dysmorphic features, motor delays, and decreased growth. We propose that defects in NatA-mediated N-terminal acetylation (NTA) lead to variable levels of neurodevelopmental disorders in humans, supporting the importance of the NatA complex in normal human development.
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http://dx.doi.org/10.1016/j.ajhg.2018.03.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5986698PMC
May 2018

Genetic and mechanistic diversity in pediatric hemophagocytic lymphohistiocytosis.

Blood 2018 07 9;132(1):89-100. Epub 2018 Apr 9.

Department of Pediatrics, Baylor College of Medicine, Houston, TX.

The HLH-2004 criteria are used to diagnose hemophagocytic lymphohistiocytosis (HLH), yet concern exists for their misapplication, resulting in suboptimal treatment of some patients. We sought to define the genomic spectrum and associated outcomes of a diverse cohort of children who met the HLH-2004 criteria. Genetic testing was performed clinically or through research-based whole-exome sequencing. Clinical metrics were analyzed with respect to genomic results. Of 122 subjects enrolled over the course of 17 years, 101 subjects received genetic testing. Biallelic familial HLH (fHLH) gene defects were identified in only 19 (19%) and correlated with presentation at younger than 1 year of age ( < .0001). Digenic fHLH variants were observed but lacked statistical support for disease association. In 28 (58%) of 48 subjects, research whole-exome sequencing analyses successfully identified likely molecular explanations, including underlying primary immunodeficiency diseases, dysregulated immune activation and proliferation disorders, and potentially novel genetic conditions. Two-thirds of patients identified by the HLH-2004 criteria had underlying etiologies for HLH, including genetic defects, autoimmunity, and malignancy. Overall survival was 45%, and increased mortality correlated with HLH triggered by infection or malignancy ( < .05). Differences in survival did not correlate with genetic profile or extent of therapy. HLH should be conceptualized as a phenotype of critical illness characterized by toxic activation of immune cells from different underlying mechanisms. In most patients with HLH, targeted sequencing of fHLH genes remains insufficient for identifying pathogenic mechanisms. Whole-exome sequencing, however, may identify specific therapeutic opportunities and affect hematopoietic stem cell transplantation options for these patients.
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http://dx.doi.org/10.1182/blood-2017-11-814244DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6034641PMC
July 2018

Biallelic variants in KIF14 cause intellectual disability with microcephaly.

Eur J Hum Genet 2018 03 17;26(3):330-339. Epub 2018 Jan 17.

Department of Genetic Medicine and Development, University of Geneva, Geneva, Switzerland.

Kinesin proteins are critical for various cellular functions such as intracellular transport and cell division, and many members of the family have been linked to monogenic disorders and cancer. We report eight individuals with intellectual disability and microcephaly from four unrelated families with parental consanguinity. In the affected individuals of each family, homozygosity for likely pathogenic variants in KIF14 were detected; two loss-of-function (p.Asn83Ilefs*3 and p.Ser1478fs), and two missense substitutions (p.Ser841Phe and p.Gly459Arg). KIF14 is a mitotic motor protein that is required for spindle localization of the mitotic citron rho-interacting kinase, CIT, also mutated in microcephaly. Our results demonstrate the involvement of KIF14 in development and reveal a wide phenotypic variability ranging from fetal lethality to moderate developmental delay and microcephaly.
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http://dx.doi.org/10.1038/s41431-017-0088-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5839044PMC
March 2018

Novel Combined Immune Deficiency and Radiation Sensitivity Blended Phenotype in an Adult with Biallelic Variations in and .

Front Immunol 2017 26;8:576. Epub 2017 May 26.

Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA.

With the advent of high-throughput genomic sequencing techniques, novel genetic etiologies are being uncovered for previously unexplained Mendelian phenotypes, and the underlying genetic architecture of disease is being unraveled. Although most of these "mendelizing" disease traits represent phenotypes caused by single-gene defects, a percentage of patients have blended phenotypes caused by pathogenic variants in multiple genes. We describe an adult patient with susceptibility to bacterial, herpesviral, and fungal infections. Immunologic defects included CD8 T cell lymphopenia, decreased T cell proliferative responses to mitogens, hypogammaglobulinemia, and radiation sensitivity. Whole-exome sequencing revealed compound heterozygous variants in . Biallelic mutations in are known to produce a spectrum of immune deficiency that includes the T cell abnormalities observed in this patient. Analyses for variants in genes associated with radiation sensitivity identified the presence of a homozygous variant of unknown significance. deficiency causes radiosensitivity, immunodeficiency, dysmorphic features, and learning difficulties syndrome and may account for the radiation sensitivity. Thus, the patient was found to have a novel blended phenotype associated with multilocus genomic variation: i.e., separate and distinct genetic defects. These findings further illustrate the clinical utility of applying genomic testing in patients with primary immunodeficiency diseases.
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http://dx.doi.org/10.3389/fimmu.2017.00576DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5445153PMC
May 2017

YY1 Haploinsufficiency Causes an Intellectual Disability Syndrome Featuring Transcriptional and Chromatin Dysfunction.

Am J Hum Genet 2017 Jun;100(6):907-925

Department of Human Genetics, Radboud University Medical Center, 6500 HB Nijmegen, the Netherlands. Electronic address:

Yin and yang 1 (YY1) is a well-known zinc-finger transcription factor with crucial roles in normal development and malignancy. YY1 acts both as a repressor and as an activator of gene expression. We have identified 23 individuals with de novo mutations or deletions of YY1 and phenotypic features that define a syndrome of cognitive impairment, behavioral alterations, intrauterine growth restriction, feeding problems, and various congenital malformations. Our combined clinical and molecular data define "YY1 syndrome" as a haploinsufficiency syndrome. Through immunoprecipitation of YY1-bound chromatin from affected individuals' cells with antibodies recognizing both ends of the protein, we show that YY1 deletions and missense mutations lead to a global loss of YY1 binding with a preferential retention at high-occupancy sites. Finally, we uncover a widespread loss of H3K27 acetylation in particular on the YY1-bound enhancers, underscoring a crucial role for YY1 in enhancer regulation. Collectively, these results define a clinical syndrome caused by haploinsufficiency of YY1 through dysregulation of key transcriptional regulators.
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http://dx.doi.org/10.1016/j.ajhg.2017.05.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5473733PMC
June 2017

Chromatin-remodeling factor SMARCD2 regulates transcriptional networks controlling differentiation of neutrophil granulocytes.

Nat Genet 2017 May 3;49(5):742-752. Epub 2017 Apr 3.

Department of Pediatrics, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-Universität München, Munich, Germany.

We identify SMARCD2 (SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily D, member 2), also known as BAF60b (BRG1/Brahma-associated factor 60b), as a critical regulator of myeloid differentiation in humans, mice, and zebrafish. Studying patients from three unrelated pedigrees characterized by neutropenia, specific granule deficiency, myelodysplasia with excess of blast cells, and various developmental aberrations, we identified three homozygous loss-of-function mutations in SMARCD2. Using mice and zebrafish as model systems, we showed that SMARCD2 controls early steps in the differentiation of myeloid-erythroid progenitor cells. In vitro, SMARCD2 interacts with the transcription factor CEBPɛ and controls expression of neutrophil proteins stored in specific granules. Defective expression of SMARCD2 leads to transcriptional and chromatin changes in acute myeloid leukemia (AML) human promyelocytic cells. In summary, SMARCD2 is a key factor controlling myelopoiesis and is a potential tumor suppressor in leukemia.
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http://dx.doi.org/10.1038/ng.3833DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5885283PMC
May 2017

Lessons learned from additional research analyses of unsolved clinical exome cases.

Genome Med 2017 03 21;9(1):26. Epub 2017 Mar 21.

Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.

Background: Given the rarity of most single-gene Mendelian disorders, concerted efforts of data exchange between clinical and scientific communities are critical to optimize molecular diagnosis and novel disease gene discovery.

Methods: We designed and implemented protocols for the study of cases for which a plausible molecular diagnosis was not achieved in a clinical genomics diagnostic laboratory (i.e. unsolved clinical exomes). Such cases were recruited to a research laboratory for further analyses, in order to potentially: (1) accelerate novel disease gene discovery; (2) increase the molecular diagnostic yield of whole exome sequencing (WES); and (3) gain insight into the genetic mechanisms of disease. Pilot project data included 74 families, consisting mostly of parent-offspring trios. Analyses performed on a research basis employed both WES from additional family members and complementary bioinformatics approaches and protocols.

Results: Analysis of all possible modes of Mendelian inheritance, focusing on both single nucleotide variants (SNV) and copy number variant (CNV) alleles, yielded a likely contributory variant in 36% (27/74) of cases. If one includes candidate genes with variants identified within a single family, a potential contributory variant was identified in a total of ~51% (38/74) of cases enrolled in this pilot study. The molecular diagnosis was achieved in 30/63 trios (47.6%). Besides this, the analysis workflow yielded evidence for pathogenic variants in disease-associated genes in 4/6 singleton cases (66.6%), 1/1 multiplex family involving three affected siblings, and 3/4 (75%) quartet families. Both the analytical pipeline and the collaborative efforts between the diagnostic and research laboratories provided insights that allowed recent disease gene discoveries (PURA, TANGO2, EMC1, GNB5, ATAD3A, and MIPEP) and increased the number of novel genes, defined in this study as genes identified in more than one family (DHX30 and EBF3).

Conclusion: An efficient genomics pipeline in which clinical sequencing in a diagnostic laboratory is followed by the detailed reanalysis of unsolved cases in a research environment, supplemented with WES data from additional family members, and subject to adjuvant bioinformatics analyses including relaxed variant filtering parameters in informatics pipelines, can enhance the molecular diagnostic yield and provide mechanistic insights into Mendelian disorders. Implementing these approaches requires collaborative clinical molecular diagnostic and research efforts.
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http://dx.doi.org/10.1186/s13073-017-0412-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5361813PMC
March 2017

First Case of Deficiency in Ecuador, Diagnosed after Whole Exome Sequencing in a Patient with Severe Cutaneous Histoplasmosis.

Front Pediatr 2017 10;5:17. Epub 2017 Feb 10.

Center for Human Immunobiology, Texas Children's Hospital, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA; Department of Pediatrics, Section of Immunology, Allergy, and Rheumatology, Baylor College of Medicine, Texas Children's Hospital, Houston, TX, USA.

Severe infections with are commonly observed in patient with secondary immunodeficiency disorders. We report a two and a half years old boy previously healthy with disseminated cutaneous histoplasmosis. Using whole exome sequencing, we found an mutation at the gene, suggesting a diagnosis of hyper-IgM (HIGM) syndrome, even in the absence of the usual features for the disease. Interestingly, the patient lives in a region endemic for histoplasmosis. The unusual infections in our case suggest that in children with severe histoplasmosis and resident in endemic areas, HIGM syndrome should be considered as a diagnosis.
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http://dx.doi.org/10.3389/fped.2017.00017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5300990PMC
February 2017

A Recurrent De Novo Variant in NACC1 Causes a Syndrome Characterized by Infantile Epilepsy, Cataracts, and Profound Developmental Delay.

Am J Hum Genet 2017 Feb 26;100(2):343-351. Epub 2017 Jan 26.

Division of Medical Genetics, Department of Pediatrics, Duke Health, Durham, NC 27710, USA. Electronic address:

Whole-exome sequencing (WES) has increasingly enabled new pathogenic gene variant identification for undiagnosed neurodevelopmental disorders and provided insights into both gene function and disease biology. Here, we describe seven children with a neurodevelopmental disorder characterized by microcephaly, profound developmental delays and/or intellectual disability, cataracts, severe epilepsy including infantile spasms, irritability, failure to thrive, and stereotypic hand movements. Brain imaging in these individuals reveals delay in myelination and cerebral atrophy. We observe an identical recurrent de novo heterozygous c.892C>T (p.Arg298Trp) variant in the nucleus accumbens associated 1 (NACC1) gene in seven affected individuals. One of the seven individuals is mosaic for this variant. NACC1 encodes a transcriptional repressor implicated in gene expression and has not previously been associated with germline disorders. The probability of finding the same missense NACC1 variant by chance in 7 out of 17,228 individuals who underwent WES for diagnoses of neurodevelopmental phenotypes is extremely small and achieves genome-wide significance (p = 1.25 × 10). Selective constraint against missense variants in NACC1 makes this excess of an identical missense variant in all seven individuals more remarkable. Our findings are consistent with a germline recurrent mutational hotspot associated with an allele-specific neurodevelopmental phenotype in NACC1.
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http://dx.doi.org/10.1016/j.ajhg.2016.12.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5294886PMC
February 2017

Homozygous and hemizygous CNV detection from exome sequencing data in a Mendelian disease cohort.

Nucleic Acids Res 2017 02;45(4):1633-1648

Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.

We developed an algorithm, HMZDelFinder, that uses whole exome sequencing (WES) data to identify rare and intragenic homozygous and hemizygous (HMZ) deletions that may represent complete loss-of-function of the indicated gene. HMZDelFinder was applied to 4866 samples in the Baylor-Hopkins Center for Mendelian Genomics (BHCMG) cohort and detected 773 HMZ deletion calls (567 homozygous or 206 hemizygous) with an estimated sensitivity of 86.5% (82% for single-exonic and 88% for multi-exonic calls) and precision of 78% (53% single-exonic and 96% for multi-exonic calls). Out of 773 HMZDelFinder-detected deletion calls, 82 were subjected to array comparative genomic hybridization (aCGH) and/or breakpoint PCR and 64 were confirmed. These include 18 single-exon deletions out of which 8 were exclusively detected by HMZDelFinder and not by any of seven other CNV detection tools examined. Further investigation of the 64 validated deletion calls revealed at least 15 pathogenic HMZ deletions. Of those, 7 accounted for 17-50% of pathogenic CNVs in different disease cohorts where 7.1-11% of the molecular diagnosis solved rate was attributed to CNVs. In summary, we present an algorithm to detect rare, intragenic, single-exon deletion CNVs using WES data; this tool can be useful for disease gene discovery efforts and clinical WES analyses.
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http://dx.doi.org/10.1093/nar/gkw1237DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5389578PMC
February 2017

Novel PIGT Variant in Two Brothers: Expansion of the Multiple Congenital Anomalies-Hypotonia Seizures Syndrome 3 Phenotype.

Genes (Basel) 2016 Nov 29;7(12). Epub 2016 Nov 29.

Department of Medical Genetics, Oslo University Hospital, 0450 Oslo, Norway.

Biallelic variants were previously reported in seven patients from three families with Multiple Congenital Anomalies-Hypotonia Seizures Syndrome 3 (MCAHS3), characterized by epileptic encephalopathy, hypotonia, global developmental delay/intellectual disability, cerebral and cerebellar atrophy, craniofacial dysmorphisms, and skeletal, ophthalmological, cardiac, and genitourinary abnormalities. We report a novel homozygous missense variant c.1079G>T (p.Gly360Val) in two brothers with several of the typical features of MCAHS3, but in addition, pyramidal tract neurological signs. Notably, they are the first patients with MCAHS3 without skeletal, cardiac, or genitourinary anomalies. encodes a crucial subunit of the glycosylphosphatidylinositol (GPI) transamidase complex, which catalyzes the attachment of proteins to GPI-anchors, attaching the proteins to the cell membrane. In vitro studies in cells from the two brothers showed reduced levels of GPI-anchors and GPI-anchored proteins on the cell surface, supporting the pathogenicity of the novel variant.
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http://dx.doi.org/10.3390/genes7120108DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5192484PMC
November 2016

A potential founder variant in in three Norwegian families with warts, molluscum contagiosum, and T-cell dysfunction.

Mol Genet Genomic Med 2016 Nov 17;4(6):604-616. Epub 2016 Sep 17.

Baylor-Hopkins Center for Mendelian Genomics (BHCMG) of the Department of Molecular and Human GeneticsBaylor College of MedicineHoustonTexas; Norwegian National Unit for Newborn ScreeningDivision of Children and Adolescent MedicineOslo University HospitalOsloNorway.

Background: Four patients from three Norwegian families presented with a common skin phenotype of warts, molluscum contagiosum, and dermatitis since early childhood, and various other immunological features. Warts are a common manifestation of (HPV), but when they are overwhelming, disseminated and/or persistent, and presenting together with other immunological features, a primary immunodeficiency disease (PIDD) may be suspected.

Methods And Results: The four patients were exome sequenced as part of a larger study for detecting genetic causes of primary immunodeficiencies. No disease-causing variants were identified in known primary immunodeficiency genes or in other disease-related OMIM genes. However, the same homozygous missense variant in (also known as ) was identified in all four patients. In each family, the variant was located within a narrow region of homozygosity, representing a potential region of autozygosity. is a protein of undetermined function. A role in T-cell activation has been suggested and the mouse protein homolog (Rltpr) is essential for costimulation of T-cell activation via CD28, and for the development of regulatory T cells. Immunophenotyping demonstrated reduced regulatory, CD4+ memory, and CD4+ follicular T cells in all four patients. In addition, they all seem to have a deficiency in IFN -synthesis in CD4+ T cells and NK cells.

Conclusions: We report a novel primary immunodeficiency, and a differential molecular diagnosis to ,,,,,,, and related diseases. The specific variant may represent a Norwegian founder variant segregating on a population-specific haplotype.
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http://dx.doi.org/10.1002/mgg3.237DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5118205PMC
November 2016

Biallelic mutations in IRF8 impair human NK cell maturation and function.

J Clin Invest 2017 01 28;127(1):306-320. Epub 2016 Nov 28.

Human NK cell deficiencies are rare yet result in severe and often fatal disease, particularly as a result of viral susceptibility. NK cells develop from hematopoietic stem cells, and few monogenic errors that specifically interrupt NK cell development have been reported. Here we have described biallelic mutations in IRF8, which encodes an interferon regulatory factor, as a cause of familial NK cell deficiency that results in fatal and severe viral disease. Compound heterozygous or homozygous mutations in IRF8 in 3 unrelated families resulted in a paucity of mature CD56dim NK cells and an increase in the frequency of the immature CD56bright NK cells, and this impairment in terminal maturation was also observed in Irf8-/-, but not Irf8+/-, mice. We then determined that impaired maturation was NK cell intrinsic, and gene expression analysis of human NK cell developmental subsets showed that multiple genes were dysregulated by IRF8 mutation. The phenotype was accompanied by deficient NK cell function and was stable over time. Together, these data indicate that human NK cells require IRF8 for development and functional maturation and that dysregulation of this function results in severe human disease, thereby emphasizing a critical role for NK cells in human antiviral defense.
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http://dx.doi.org/10.1172/JCI86276DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5199714PMC
January 2017