Publications by authors named "Hana Lango Allen"

37 Publications

GIGYF1 loss of function is associated with clonal mosaicism and adverse metabolic health.

Nat Commun 2021 07 7;12(1):4178. Epub 2021 Jul 7.

MRC Epidemiology Unit, Institute of Metabolic Science, University of Cambridge, Cambridge, UK.

Mosaic loss of chromosome Y (LOY) in leukocytes is the most common form of clonal mosaicism, caused by dysregulation in cell-cycle and DNA damage response pathways. Previous genetic studies have focussed on identifying common variants associated with LOY, which we now extend to rarer, protein-coding variation using exome sequences from 82,277 male UK Biobank participants. We find that loss of function of two genes-CHEK2 and GIGYF1-reach exome-wide significance. Rare alleles in GIGYF1 have not previously been implicated in any complex trait, but here loss-of-function carriers exhibit six-fold higher susceptibility to LOY (OR = 5.99 [3.04-11.81], p = 1.3 × 10). These same alleles are also associated with adverse metabolic health, including higher susceptibility to Type 2 Diabetes (OR = 6.10 [3.51-10.61], p = 1.8 × 10), 4 kg higher fat mass (p = 1.3 × 10), 2.32 nmol/L lower serum IGF1 levels (p = 1.5 × 10) and 4.5 kg lower handgrip strength (p = 4.7 × 10) consistent with proposed GIGYF1 enhancement of insulin and IGF-1 receptor signalling. These associations are mirrored by a common variant nearby associated with the expression of GIGYF1. Our observations highlight a potential direct connection between clonal mosaicism and metabolic health.
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http://dx.doi.org/10.1038/s41467-021-24504-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8263756PMC
July 2021

Differential IRF8 Transcription Factor Requirement Defines Two Pathways of Dendritic Cell Development in Humans.

Immunity 2020 08 30;53(2):353-370.e8. Epub 2020 Jul 30.

Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK; Northern Centre for Cancer Care, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne NE7 7DN, UK. Electronic address:

The formation of mammalian dendritic cells (DCs) is controlled by multiple hematopoietic transcription factors, including IRF8. Loss of IRF8 exerts a differential effect on DC subsets, including plasmacytoid DCs (pDCs) and the classical DC lineages cDC1 and cDC2. In humans, cDC2-related subsets have been described including AXLSIGLEC6 pre-DC, DC2 and DC3. The origin of this heterogeneity is unknown. Using high-dimensional analysis, in vitro differentiation, and an allelic series of human IRF8 deficiency, we demonstrated that cDC2 (CD1cDC) heterogeneity originates from two distinct pathways of development. The lymphoid-primed IRF8 pathway, marked by CD123 and BTLA, carried pDC, cDC1, and DC2 trajectories, while the common myeloid IRF8 pathway, expressing SIRPA, formed DC3s and monocytes. We traced distinct trajectories through the granulocyte-macrophage progenitor (GMP) compartment showing that AXLSIGLEC6 pre-DCs mapped exclusively to the DC2 pathway. In keeping with their lower requirement for IRF8, DC3s expand to replace DC2s in human partial IRF8 deficiency.
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http://dx.doi.org/10.1016/j.immuni.2020.07.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7447982PMC
August 2020

Whole-genome sequencing of patients with rare diseases in a national health system.

Nature 2020 07 24;583(7814):96-102. Epub 2020 Jun 24.

Department of Medical Genetics, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.

Most patients with rare diseases do not receive a molecular diagnosis and the aetiological variants and causative genes for more than half such disorders remain to be discovered. Here we used whole-genome sequencing (WGS) in a national health system to streamline diagnosis and to discover unknown aetiological variants in the coding and non-coding regions of the genome. We generated WGS data for 13,037 participants, of whom 9,802 had a rare disease, and provided a genetic diagnosis to 1,138 of the 7,065 extensively phenotyped participants. We identified 95 Mendelian associations between genes and rare diseases, of which 11 have been discovered since 2015 and at least 79 are confirmed to be aetiological. By generating WGS data of UK Biobank participants, we found that rare alleles can explain the presence of some individuals in the tails of a quantitative trait for red blood cells. Finally, we identified four novel non-coding variants that cause disease through the disruption of transcription of ARPC1B, GATA1, LRBA and MPL. Our study demonstrates a synergy by using WGS for diagnosis and aetiological discovery in routine healthcare.
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http://dx.doi.org/10.1038/s41586-020-2434-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7610553PMC
July 2020

Whole-genome sequencing of a sporadic primary immunodeficiency cohort.

Nature 2020 07 6;583(7814):90-95. Epub 2020 May 6.

Institute of Immunity and Transplantation, University College London, London, UK.

Primary immunodeficiency (PID) is characterized by recurrent and often life-threatening infections, autoimmunity and cancer, and it poses major diagnostic and therapeutic challenges. Although the most severe forms of PID are identified in early childhood, most patients present in adulthood, typically with no apparent family history and a variable clinical phenotype of widespread immune dysregulation: about 25% of patients have autoimmune disease, allergy is prevalent and up to 10% develop lymphoid malignancies. Consequently, in sporadic (or non-familial) PID genetic diagnosis is difficult and the role of genetics is not well defined. Here we address these challenges by performing whole-genome sequencing in a large PID cohort of 1,318 participants. An analysis of the coding regions of the genome in 886 index cases of PID found that disease-causing mutations in known genes that are implicated in monogenic PID occurred in 10.3% of these patients, and a Bayesian approach (BeviMed) identified multiple new candidate PID-associated genes, including IVNS1ABP. We also examined the noncoding genome, and found deletions in regulatory regions that contribute to disease causation. In addition, we used a genome-wide association study to identify loci that are associated with PID, and found evidence for the colocalization of-and interplay between-novel high-penetrance monogenic variants and common variants (at the PTPN2 and SOCS1 loci). This begins to explain the contribution of common variants to the variable penetrance and phenotypic complexity that are observed in PID. Thus, using a cohort-based whole-genome-sequencing approach in the diagnosis of PID can increase diagnostic yield and further our understanding of the key pathways that influence immune responsiveness in humans.
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http://dx.doi.org/10.1038/s41586-020-2265-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7334047PMC
July 2020

ADA2 deficiency complicated by EBV-driven lymphoproliferative disease.

Clin Immunol 2020 06 27;215:108443. Epub 2020 Apr 27.

Medical Research Council Toxicology Unit, University of Cambridge, Cambridge, United Kingdom; Department of Immunology, Addenbrooke's Hospital, Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom; Department of Medicine, University of Cambridge, Cambridge, United Kingdom. Electronic address:

A 29-year old male with recurrent respiratory and skin infections, anaemia and neutropaenia during childhood required immunoglobulin replacement for antibody deficiency from age 16. He remained relatively well until age 28 when he presented with a two-week history of fatigue, sore throat, fever and productive cough. He was found to have EBV viraemia and splenomegaly and a diagnosis of EBV-driven lymphoproliferative disease was made following bone marrow trephine. Family history was notable with three siblings: a healthy sister and two brothers with anaemia and neutropaenia; one who succumbed to septicaemia secondary to neutropaenic enterocolitis age 5 and another who developed intestinal vasculitis and antibody deficiency and had a successful haemopoetic stem cell transplant. The proband's DNA underwent targeted sequencing of 279 genes associated with immunodeficiency (GRID panel). The best candidates were two ADA2 variants, p.Arg169Gln (R169Q) and p.Asn370Lys (N370K). Sanger sequencing and co-segregation of variants in the parents, unaffected sister and all three affected brothers was fully consistent with compound heterozygous inheritance. Subsequent whole genome sequencing of the proband identified no other potential causal variants. ADA2 activity was consistent with a diagnosis of ADA2 deficiency in affected family members. This is the first description of EBV-driven lymphoproliferative disease in ADA2 deficiency. ADA2 deficiency may cause susceptibility to severe EBV-induced disease and we would recommend that EBV status and viral load is monitored in patients with this diagnosis and allogeneic SCT is considered at an early stage for patients whose ADA2 deficiency is associated with significant complications.
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http://dx.doi.org/10.1016/j.clim.2020.108443DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7306156PMC
June 2020

Characterization of the clinical and immunologic phenotype and management of 157 individuals with 56 distinct heterozygous NFKB1 mutations.

J Allergy Clin Immunol 2020 10 9;146(4):901-911. Epub 2020 Apr 9.

Primary Immunodeficiencies Unit, Hospital Dona Estefania, Centro Hospitalar de Lisboa Central, Lisbon, Portugal.

Background: An increasing number of NFKB1 variants are being identified in patients with heterogeneous immunologic phenotypes.

Objective: To characterize the clinical and cellular phenotype as well as the management of patients with heterozygous NFKB1 mutations.

Methods: In a worldwide collaborative effort, we evaluated 231 individuals harboring 105 distinct heterozygous NFKB1 variants. To provide evidence for pathogenicity, each variant was assessed in silico; in addition, 32 variants were assessed by functional in vitro testing of nuclear factor of kappa light polypeptide gene enhancer in B cells (NF-κB) signaling.

Results: We classified 56 of the 105 distinct NFKB1 variants in 157 individuals from 68 unrelated families as pathogenic. Incomplete clinical penetrance (70%) and age-dependent severity of NFKB1-related phenotypes were observed. The phenotype included hypogammaglobulinemia (88.9%), reduced switched memory B cells (60.3%), and respiratory (83%) and gastrointestinal (28.6%) infections, thus characterizing the disorder as primary immunodeficiency. However, the high frequency of autoimmunity (57.4%), lymphoproliferation (52.4%), noninfectious enteropathy (23.1%), opportunistic infections (15.7%), autoinflammation (29.6%), and malignancy (16.8%) identified NF-κB1-related disease as an inborn error of immunity with immune dysregulation, rather than a mere primary immunodeficiency. Current treatment includes immunoglobulin replacement and immunosuppressive agents.

Conclusions: We present a comprehensive clinical overview of the NF-κB1-related phenotype, which includes immunodeficiency, autoimmunity, autoinflammation, and cancer. Because of its multisystem involvement, clinicians from each and every medical discipline need to be made aware of this autosomal-dominant disease. Hematopoietic stem cell transplantation and NF-κB1 pathway-targeted therapeutic strategies should be considered in the future.
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http://dx.doi.org/10.1016/j.jaci.2019.11.051DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8246418PMC
October 2020

Thousands of missing variants in the UK Biobank are recoverable by genome realignment.

Ann Hum Genet 2020 05 31;84(3):214-220. Epub 2020 Mar 31.

Department of Medicine, University of California San Diego, La Jolla, California.

The UK Biobank is an unprecedented resource for human disease research. In March 2019, 49,997 exomes were made publicly available to investigators. Here we note that thousands of variant calls are unexpectedly absent from this dataset, with 641 genes showing zero variation. We show that the reason for this was an erroneous read alignment to the GRCh38 reference. The missing variants can be recovered by modifying read alignment parameters to correctly handle the expanded set of contigs available in the human genome reference. Given the size and complexity of such population scale datasets, we propose a simple heuristic that can uncover systematic errors using summary data accessible to most investigators.
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http://dx.doi.org/10.1111/ahg.12383DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7402360PMC
May 2020

Predicting the Occurrence of Variants in RAG1 and RAG2.

J Clin Immunol 2019 10 6;39(7):688-701. Epub 2019 Aug 6.

Department of Clinical Immunology and Allergy, St James's University Hospital, Beckett Street, Leeds, UK.

While widespread genome sequencing ushers in a new era of preventive medicine, the tools for predictive genomics are still lacking. Time and resource limitations mean that human diseases remain uncharacterized because of an inability to predict clinically relevant genetic variants. A strategy of targeting highly conserved protein regions is used commonly in functional studies. However, this benefit is lost for rare diseases where the attributable genes are mostly conserved. An immunological disorder exemplifying this challenge occurs through damaging mutations in RAG1 and RAG2 which presents at an early age with a distinct phenotype of life-threatening immunodeficiency or autoimmunity. Many tools exist for variant pathogenicity prediction, but these cannot account for the probability of variant occurrence. Here, we present a method that predicts the likelihood of mutation for every amino acid residue in the RAG1 and RAG2 proteins. Population genetics data from approximately 146,000 individuals was used for rare variant analysis. Forty-four known pathogenic variants reported in patients and recombination activity measurements from 110 RAG1/2 mutants were used to validate calculated scores. Probabilities were compared with 98 currently known human cases of disease. A genome sequence dataset of 558 patients who have primary immunodeficiency but that are negative for RAG deficiency were also used as validation controls. We compared the difference between mutation likelihood and pathogenicity prediction. Our method builds a map of most probable mutations allowing pre-emptive functional analysis. This method may be applied to other diseases with hopes of improving preparedness for clinical diagnosis.
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http://dx.doi.org/10.1007/s10875-019-00670-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6754361PMC
October 2019

Loss of the interleukin-6 receptor causes immunodeficiency, atopy, and abnormal inflammatory responses.

J Exp Med 2019 09 24;216(9):1986-1998. Epub 2019 Jun 24.

Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD.

IL-6 excess is central to the pathogenesis of multiple inflammatory conditions and is targeted in clinical practice by immunotherapy that blocks the IL-6 receptor encoded by We describe two patients with homozygous mutations in who presented with recurrent infections, abnormal acute-phase responses, elevated IgE, eczema, and eosinophilia. This study identifies a novel primary immunodeficiency, clarifying the contribution of IL-6 to the phenotype of patients with mutations in , and genes encoding different components of the IL-6 signaling pathway, and alerts us to the potential toxicity of drugs targeting the IL-6R.
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http://dx.doi.org/10.1084/jem.20190344DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6719421PMC
September 2019

A Specific CNOT1 Mutation Results in a Novel Syndrome of Pancreatic Agenesis and Holoprosencephaly through Impaired Pancreatic and Neurological Development.

Am J Hum Genet 2019 05 18;104(5):985-989. Epub 2019 Apr 18.

Wellcome Sanger Institute, CB10 1SA Hinxton, UK. Electronic address:

We report a recurrent CNOT1 de novo missense mutation, GenBank: NM_016284.4; c.1603C>T (p.Arg535Cys), resulting in a syndrome of pancreatic agenesis and abnormal forebrain development in three individuals and a similar phenotype in mice. CNOT1 is a transcriptional repressor that has been suggested as being critical for maintaining embryonic stem cells in a pluripotent state. These findings suggest that CNOT1 plays a critical role in pancreatic and neurological development and describe a novel genetic syndrome of pancreatic agenesis and holoprosencephaly.
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http://dx.doi.org/10.1016/j.ajhg.2019.03.018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6506862PMC
May 2019

Pathogenic NFKB2 variant in the ankyrin repeat domain (R635X) causes a variable antibody deficiency.

Clin Immunol 2019 06 3;203:23-27. Epub 2019 Apr 3.

Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, Department of Pediatric Immunology, Rheumatology and Infectious diseases, Meibergdreef 9, Amsterdam, The Netherlands; Amsterdam UMC, University of Amsterdam, Department of Experimental Immunology, Amsterdam Infection & Immunity Institute, Meibergdreef 9, Amsterdam, The Netherlands. Electronic address:

Genetic studies are identifying an increasing number of monogenic causes of Common Variable Immunodeficiency (CVID). Pathogenic variants in the C-terminus of NFKB2 have been identified in the subset of CVID patients whose immunodeficiency is associated with ectodermal dysplasia and central adrenal insufficiency. We describe 2 unrelated CVID pedigrees with 4 cases of pathogenic stop gain variants (c.1903C > T) in the ankyrin repeat domain (ARD) of NF-κB2, leading to a premature truncation of the protein at p.Arg635Term (R635X). By immunophenotyping and functional ex vivo B- and T-cell experiments we characterized the variant by reduced class-switched memory B-cell counts and immature plasmablasts, unable to produce IgG and IgA. Features of a poor proliferative T-cell response and reduced expansion of CD4CXCR5 T cells was only observed in the two clinically affected index cases without any clear clinical correlate. In conclusion, pathogenic stop variants in the ARD of NFKB2 can cause 'infection-only' CVID with an abnormal B-cell phenotype and a variable clinical penetrance.
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http://dx.doi.org/10.1016/j.clim.2019.03.010DOI Listing
June 2019

Copy number variation of in familial dystonic tremor.

Neurol Genet 2019 Feb 4;5(1):e307. Epub 2019 Feb 4.

Medical Research (Level 4) (V.A., B.A.C., G.V.H., H.H., A.S.-N., J.K.C., E.L.B., A.H.C.), University of Exeter Medical School, RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, United Kingdom; Reta Lila Weston Institute of Neurological Studies (V.A., T.T.W.), UCL Institute of Neurology, London, United Kingdom; Department of Neurology (T.I.), Government Medical College, Thiruvananthapuram, Kerala, India; Department of Anatomy and Microbiology (R.S.), Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India; Clinical Neuroscience (C.P.), Royal Free Campus, UCL Institute of Neurology, London, United Kingdom; Institute of Psychological Medicine and Clinical Neurosciences (K.P.), Cardiff University, Cardiff, United Kingdom; Taub Institute for Research on Alzheimer's Disease and the Aging Brain (L.N.C.), Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY; Institute of Biomedical and Clinical Science (R.C., H.L.A., M.W.), University of Exeter Medical School, United Kingdom; and Departments of Neurology and Chronic Disease Epidemiology and Center for Neuroepidemiology and Clinical Neurological Research (E.D.L.), Yale School of Medicine and Yale School of Public Health, Yale University, New Haven, CT.

Objective: To elucidate the genetic cause of a large 5 generation South Indian family with multiple individuals with predominantly an upper limb postural tremor and posturing in keeping with another form of tremor, namely, dystonic tremor.

Methods: Whole-genome single nucleotide polymorphism (SNP) microarray analysis was undertaken to look for copy number variants in the affected individuals.

Results: Whole-genome SNP microarray studies identified a tandem duplicated genomic segment of chromosome 15q24 present in all affected family members. Whole-genome sequencing demonstrated that it comprised a ∼550-kb tandem duplication encompassing the entire gene.

Conclusions: The identification of a genomic duplication as the likely molecular cause of this condition, resulting in an additional gene copy in affected cases, adds further support for a causal role of this gene in tremor disorders and implicates increased expression levels of as a potential pathogenic mechanism.
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http://dx.doi.org/10.1212/NXG.0000000000000307DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6384021PMC
February 2019

Loss-of-function nuclear factor κB subunit 1 (NFKB1) variants are the most common monogenic cause of common variable immunodeficiency in Europeans.

J Allergy Clin Immunol 2018 10 2;142(4):1285-1296. Epub 2018 Mar 2.

Department of Pediatric Hematology, Immunology and Infectious Diseases, Emma Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands; Department of Experimental Immunology, Academic Medical Center, Amsterdam, The Netherlands; Department of Internal Medicine, Academic Medical Center, Amsterdam, The Netherlands. Electronic address:

Background: The genetic cause of primary immunodeficiency disease (PID) carries prognostic information.

Objective: We conducted a whole-genome sequencing study assessing a large proportion of the NIHR BioResource-Rare Diseases cohort.

Methods: In the predominantly European study population of principally sporadic unrelated PID cases (n = 846), a novel Bayesian method identified nuclear factor κB subunit 1 (NFKB1) as one of the genes most strongly associated with PID, and the association was explained by 16 novel heterozygous truncating, missense, and gene deletion variants. This accounted for 4% of common variable immunodeficiency (CVID) cases (n = 390) in the cohort. Amino acid substitutions predicted to be pathogenic were assessed by means of analysis of structural protein data. Immunophenotyping, immunoblotting, and ex vivo stimulation of lymphocytes determined the functional effects of these variants. Detailed clinical and pedigree information was collected for genotype-phenotype cosegregation analyses.

Results: Both sporadic and familial cases demonstrated evidence of the noninfective complications of CVID, including massive lymphadenopathy (24%), unexplained splenomegaly (48%), and autoimmune disease (48%), features prior studies correlated with worse clinical prognosis. Although partial penetrance of clinical symptoms was noted in certain pedigrees, all carriers have a deficiency in B-lymphocyte differentiation. Detailed assessment of B-lymphocyte numbers, phenotype, and function identifies the presence of an increased CD21 B-cell population. Combined with identification of the disease-causing variant, this distinguishes between healthy subjects, asymptomatic carriers, and clinically affected cases.

Conclusion: We show that heterozygous loss-of-function variants in NFKB1 are the most common known monogenic cause of CVID, which results in a temporally progressive defect in the formation of immunoglobulin-producing B cells.
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http://dx.doi.org/10.1016/j.jaci.2018.01.039DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6148345PMC
October 2018

Diagnosis of lethal or prenatal-onset autosomal recessive disorders by parental exome sequencing.

Prenat Diagn 2018 01 3;38(1):33-43. Epub 2017 Dec 3.

Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, Vic, Australia.

Objective: Rare genetic disorders resulting in prenatal or neonatal death are genetically heterogeneous, but testing is often limited by the availability of fetal DNA, leaving couples without a potential prenatal test for future pregnancies. We describe our novel strategy of exome sequencing parental DNA samples to diagnose recessive monogenic disorders in an audit of the first 50 couples referred.

Method: Exome sequencing was carried out in a consecutive series of 50 couples who had 1 or more pregnancies affected with a lethal or prenatal-onset disorder. In all cases, there was insufficient DNA for exome sequencing of the affected fetus. Heterozygous rare variants (MAF < 0.001) in the same gene in both parents were selected for analysis. Likely, disease-causing variants were tested in fetal DNA to confirm co-segregation.

Results: Parental exome analysis identified heterozygous pathogenic (or likely pathogenic) variants in 24 different genes in 26/50 couples (52%). Where 2 or more fetuses were affected, a genetic diagnosis was obtained in 18/29 cases (62%). In most cases, the clinical features were typical of the disorder, but in others, they result from a hypomorphic variant or represent the most severe form of a variable phenotypic spectrum.

Conclusion: We conclude that exome sequencing of parental samples is a powerful strategy with high clinical utility for the genetic diagnosis of lethal or prenatal-onset recessive disorders. © 2017 The Authors Prenatal Diagnosis published by John Wiley & Sons Ltd.
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http://dx.doi.org/10.1002/pd.5175DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5836855PMC
January 2018

Recessively Inherited Mutations Cause Autoimmunity Presenting as Neonatal Diabetes.

Diabetes 2017 08 4;66(8):2316-2322. Epub 2017 May 4.

Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, U.K.

Young-onset autoimmune diabetes associated with additional autoimmunity usually reflects a polygenic predisposition, but rare cases result from monogenic autoimmunity. Diagnosing monogenic autoimmunity is crucial for patients' prognosis and clinical management. We sought to identify novel genetic causes of autoimmunity presenting with neonatal diabetes (NDM) (diagnosis <6 months). We performed exome sequencing in a patient with NDM and autoimmune lymphoproliferative syndrome and his unrelated, unaffected parents and identified compound heterozygous null mutations in Biallelic mutations cause common variable immunodeficiency-8; however, NDM has not been confirmed in this disorder. We sequenced in 169 additional patients with diabetes diagnosed <1 year without mutations in the 24 known NDM genes. We identified recessive null mutations in 8 additional probands, of which, 3 had NDM (<6 months). Diabetes was the presenting feature in 6 of 9 probands. Six of 17 (35%) patients born to consanguineous parents and with additional early-onset autoimmunity had recessive mutations. testing should be considered in patients with diabetes diagnosed <12 months, particularly if they have additional autoimmunity or are born to consanguineous parents. A genetic diagnosis is important as it can enable personalized therapy with abatacept, a CTLA-4 mimetic, and inform genetic counseling.
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http://dx.doi.org/10.2337/db17-0040DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5524180PMC
August 2017

Polycystic Kidney Disease with Hyperinsulinemic Hypoglycemia Caused by a Promoter Mutation in Phosphomannomutase 2.

J Am Soc Nephrol 2017 08 3;28(8):2529-2539. Epub 2017 Apr 3.

University College London Centre for Nephrology, University College London, London, United Kingdom.

Hyperinsulinemic hypoglycemia (HI) and congenital polycystic kidney disease (PKD) are rare, genetically heterogeneous disorders. The co-occurrence of these disorders (HIPKD) in 17 children from 11 unrelated families suggested an unrecognized genetic disorder. Whole-genome linkage analysis in five informative families identified a single significant locus on chromosome 16p13.2 (logarithm of odds score 6.5). Sequencing of the coding regions of all linked genes failed to identify biallelic mutations. Instead, we found in all patients a promoter mutation (c.-167G>T) in the phosphomannomutase 2 gene (), either homozygous or with coding mutations. encodes a key enzyme in N-glycosylation. Abnormal glycosylation has been associated with PKD, and we found that deglycosylation in cultured pancreatic cells altered insulin secretion. Recessive coding mutations in cause congenital disorder of glycosylation type 1a (CDG1A), a devastating multisystem disorder with prominent neurologic involvement. Yet our patients did not exhibit the typical clinical or diagnostic features of CDG1A. the promoter mutation associated with decreased transcriptional activity in patient kidney cells and impaired binding of the transcription factor ZNF143. analysis suggested an important role of ZNF143 for the formation of a chromatin loop including We propose that the promoter mutation alters tissue-specific chromatin loop formation, with consequent organ-specific deficiency of PMM2 leading to the restricted phenotype of HIPKD. Our findings extend the spectrum of genetic causes for both HI and PKD and provide insights into gene regulation and pleiotropy.
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http://dx.doi.org/10.1681/ASN.2016121312DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5533241PMC
August 2017

SOS1 frameshift mutations cause pure mucosal neuroma syndrome, a clinical phenotype distinct from multiple endocrine neoplasia type 2B.

Clin Endocrinol (Oxf) 2016 May 4;84(5):715-9. Epub 2016 Feb 4.

Department of Molecular Genetics, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK.

Background: Mucosal neuromas, thickened corneal nerves and marfanoid body habitus are characteristic phenotypic features of multiple endocrine neoplasia type 2B (MEN2B) and often provide an early clue to the diagnosis of the syndrome. Rarely, patients present with typical physical features of MEN2B but without associated endocrinopathies (medullary thyroid carcinoma or pheochromocytoma) or a RET gene mutation; this clinical presentation is thought to represent a distinct condition termed 'pure mucosal neuroma syndrome'.

Methods: Exome sequencing was performed in two unrelated probands with mucosal neuromas, thickened corneal nerves and marfanoid body habitus, but no MEN2B-associated endocrinopathy or RET gene mutation. Sanger sequencing was performed to confirm mutations detected by exome sequencing and to test in family members and 3 additional unrelated index patients with mucosal neuromas or thickened corneal nerves.

Results: A heterozygous SOS1 gene frameshift mutation (c.3266dup or c.3248dup) was identified in each proband. Sanger sequencing showed that proband 1 inherited the c.3266dup mutation from his affected mother, while the c.3248dup mutation had arisen de novo in proband 2. Sanger sequencing also identified one further novel SOS1 mutation (c.3254dup) in one of the 3 additional index patients.

Conclusion: Our results demonstrate the existence of pure mucosal neuroma syndrome as a clinical entity distinct from MEN2B that can now be diagnosed by genetic testing.
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http://dx.doi.org/10.1111/cen.13008DOI Listing
May 2016

Biallelic RFX6 mutations can cause childhood as well as neonatal onset diabetes mellitus.

Eur J Hum Genet 2015 Dec 12;23(12):1744-8. Epub 2015 Aug 12.

Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK.

Neonatal diabetes is a highly genetically heterogeneous disorder. There are over 20 distinct syndromic and non-syndromic forms, including dominant, recessive and X-linked subtypes. Biallelic truncating or mis-sense mutations in the DNA-binding domain of the RFX6 transcription factor cause an autosomal recessive, syndromic form of neonatal diabetes previously described as Mitchell-Riley syndrome. In all, eight cases have been reported, with the age at onset of diabetes in the first 2 weeks of life. Here we report two individuals born to double first cousins in whom intestinal atresias consistent with a diagnosis of Mitchell-Riley syndrome were diagnosed at birth, but in whom diabetes did not present until the ages of 3 and 6 years. Novel compound heterozygous RFX6 nonsense mutations (p.Arg726X/p.Arg866X) were identified at the 3' end of the gene. The later onset of diabetes in these patients may be due to incomplete inactivation of RFX6. Genetic testing for RFX6 mutations should be considered in patients presenting with intestinal atresias in the absence of neonatal diabetes.
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http://dx.doi.org/10.1038/ejhg.2015.161DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4795203PMC
December 2015

The effect of early, comprehensive genomic testing on clinical care in neonatal diabetes: an international cohort study.

Lancet 2015 Sep 28;386(9997):957-63. Epub 2015 Jul 28.

Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK. Electronic address:

Background: Traditional genetic testing focusses on analysis of one or a few genes according to clinical features; this approach is changing as improved sequencing methods enable simultaneous analysis of several genes. Neonatal diabetes is the presenting feature of many discrete clinical phenotypes defined by different genetic causes. Genetic subtype defines treatment, with improved glycaemic control on sulfonylurea treatment for most patients with potassium channel mutations. We investigated the effect of early, comprehensive testing of all known genetic causes of neonatal diabetes.

Methods: In this large, international, cohort study, we studied patients with neonatal diabetes diagnosed with diabetes before 6 months of age who were referred from 79 countries. We identified mutations by comprehensive genetic testing including Sanger sequencing, 6q24 methylation analysis, and targeted next-generation sequencing of all known neonatal diabetes genes.

Findings: Between January, 2000, and August, 2013, genetic testing was done in 1020 patients (571 boys, 449 girls). Mutations in the potassium channel genes were the most common cause (n=390) of neonatal diabetes, but were identified less frequently in consanguineous families (12% in consanguineous families vs 46% in non-consanguineous families; p<0·0001). Median duration of diabetes at the time of genetic testing decreased from more than 4 years before 2005 to less than 3 months after 2012. Earlier referral for genetic testing affected the clinical phenotype. In patients with genetically diagnosed Wolcott-Rallison syndrome, 23 (88%) of 26 patients tested within 3 months from diagnosis had isolated diabetes, compared with three (17%) of 18 patients referred later (>4 years; p<0·0001), in whom skeletal and liver involvement was common. Similarly, for patients with genetically diagnosed transient neonatal diabetes, the diabetes had remitted in only ten (10%) of 101 patients tested early (<3 months) compared with 60 (100%) of the 60 later referrals (p<0·0001).

Interpretation: Patients are now referred for genetic testing closer to their presentation with neonatal diabetes. Comprehensive testing of all causes identified causal mutations in more than 80% of cases. The genetic result predicts the best diabetes treatment and development of related features. This model represents a new framework for clinical care with genetic diagnosis preceding development of clinical features and guiding clinical management.

Funding: Wellcome Trust and Diabetes UK.
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http://dx.doi.org/10.1016/S0140-6736(15)60098-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4772451PMC
September 2015

Activating germline mutations in STAT3 cause early-onset multi-organ autoimmune disease.

Nat Genet 2014 Aug 20;46(8):812-814. Epub 2014 Jul 20.

Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, EX2 5DW, UK.

Monogenic causes of autoimmunity provide key insights into the complex regulation of the immune system. We report a new monogenic cause of autoimmunity resulting from de novo germline activating STAT3 mutations in five individuals with a spectrum of early-onset autoimmune disease, including type 1 diabetes. These findings emphasize the critical role of STAT3 in autoimmune disease and contrast with the germline inactivating STAT3 mutations that result in hyper IgE syndrome.
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http://dx.doi.org/10.1038/ng.3040DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4129488PMC
August 2014

An exome sequencing strategy to diagnose lethal autosomal recessive disorders.

Eur J Hum Genet 2015 Mar 25;23(3):401-4. Epub 2014 Jun 25.

Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK.

Rare disorders resulting in prenatal or neonatal death are genetically heterogeneous. For some conditions, affected fetuses can be diagnosed by ultrasound scan, but this is not usually possible until mid-gestation. There is often limited fetal DNA available for investigation. We investigated a strategy for diagnosing autosomal recessive lethal disorders in non-consanguineous pedigrees with multiple affected fetuses. Exome sequencing was performed to identify genes where each parent is heterozygous for a rare non-synonymous-coding or splicing variant. Putative pathogenic variants were tested for cosegregation in affected fetuses and unaffected siblings. In eight couples of European ancestry, we found on average 1.75 genes (range 0-4) where both parents were heterozygous for rare potentially deleterious variants. A proof-of-principle study detected heterozygous DYNC2H1 variants in a couple whose five fetuses had short-rib polydactyly. Prospective analysis of two couples with multiple pregnancy terminations for fetal akinesia syndrome was performed and a diagnosis was obtained in both the families. The first couple were each heterozygous for a previously reported GLE1 variant, p.Arg569His or p.Val617Met; both were inherited by their two affected fetuses. The second couple were each heterozygous for a novel RYR1 variant, c.14130-2A>G or p.Ser3074Phe; both were inherited by their three affected fetuses but not by their unaffected child. Biallelic GLE1 and RYR1 disease-causing variants have been described in other cases with fetal akinesia syndrome. We conclude that exome sequencing of parental samples can be an effective tool for diagnosing lethal recessive disorders in outbred couples. This permits early prenatal diagnosis in future pregnancies.
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http://dx.doi.org/10.1038/ejhg.2014.120DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4205099PMC
March 2015

GATA4 mutations are a cause of neonatal and childhood-onset diabetes.

Diabetes 2014 Aug 2;63(8):2888-94. Epub 2014 Apr 2.

Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, U.K.

The GATA family zinc finger transcription factors GATA4 and GATA6 are known to play important roles in the development of the pancreas. In mice, both Gata4 and Gata6 are required for pancreatic development. In humans, GATA6 haploinsufficiency can cause pancreatic agenesis and heart defects. Congenital heart defects also are common in patients with GATA4 mutations and deletions, but the role of GATA4 in the developing human pancreas is unproven. We report five patients with deletions (n = 4) or mutations of the GATA4 gene who have diabetes and a variable exocrine phenotype. In four cases, diabetes presented in the neonatal period (age at diagnosis 1-7 days). A de novo GATA4 missense mutation (p.N273K) was identified in a patient with complete absence of the pancreas confirmed at postmortem. This mutation affects a highly conserved residue located in the second zinc finger domain of the GATA4 protein. In vitro studies showed reduced DNA binding and transactivational activity of the mutant protein. We show that GATA4 mutations/deletions are a cause of neonatal or childhood-onset diabetes with or without exocrine insufficiency. These results confirm a role for GATA4 in normal development of the human pancreas.
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http://dx.doi.org/10.2337/db14-0061DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6850908PMC
August 2014

Next generation sequencing of chromosomal rearrangements in patients with split-hand/split-foot malformation provides evidence for DYNC1I1 exonic enhancers of DLX5/6 expression in humans.

J Med Genet 2014 Apr 23;51(4):264-7. Epub 2014 Jan 23.

Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK.

Objective: Split-hand/foot malformation type 1 is an autosomal dominant condition with reduced penetrance and variable expression. We report three individuals from two families with split-hand/split-foot malformation (SHFM) in whom next generation sequencing was performed to investigate the cause of their phenotype.

Methods And Results: The first proband has a de novo balanced translocation t(2;7)(p25.1;q22) identified by karyotyping. Whole genome sequencing showed that the chromosome 7 breakpoint is situated within the SHFM1 locus on chromosome 7q21.3. This separates the DYNC1I1 exons recently identified as limb enhancers in mouse studies from their target genes, DLX5 and DLX6. In the second family, X-linked recessive inheritance was suspected and exome sequencing was performed to search for a mutation in the affected proband and his uncle. No coding mutation was found within the SHFM2 locus at Xq26 or elsewhere in the exome, but a 106 kb deletion within the SHFM1 locus was detected through copy number analysis. Genome sequencing of the deletion breakpoints showed that the DLX5 and DLX6 genes are disomic but the putative DYNC1I1 exon 15 and 17 enhancers are deleted.

Conclusions: Exome sequencing identified a 106 kb deletion that narrows the SHFM1 critical region from 0.9 to 0.1 Mb and confirms a key role of DYNC1I1 exonic enhancers in normal limb formation in humans.
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http://dx.doi.org/10.1136/jmedgenet-2013-102142DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3963551PMC
April 2014

Analysis of transcription factors key for mouse pancreatic development establishes NKX2-2 and MNX1 mutations as causes of neonatal diabetes in man.

Cell Metab 2014 Jan;19(1):146-54

Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK. Electronic address:

Understanding transcriptional regulation of pancreatic development is required to advance current efforts in developing beta cell replacement therapies for patients with diabetes. Current knowledge of key transcriptional regulators has predominantly come from mouse studies, with rare, naturally occurring mutations establishing their relevance in man. This study used a combination of homozygosity analysis and Sanger sequencing in 37 consanguineous patients with permanent neonatal diabetes to search for homozygous mutations in 29 transcription factor genes important for murine pancreatic development. We identified homozygous mutations in 7 different genes in 11 unrelated patients and show that NKX2-2 and MNX1 are etiological genes for neonatal diabetes, thus confirming their key role in development of the human pancreas. The similar phenotype of the patients with recessive mutations and mice with inactivation of a transcription factor gene support there being common steps critical for pancreatic development and validate the use of rodent models for beta cell development.
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http://dx.doi.org/10.1016/j.cmet.2013.11.021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3887257PMC
January 2014

Recessive mutations in a distal PTF1A enhancer cause isolated pancreatic agenesis.

Nat Genet 2014 Jan 10;46(1):61-64. Epub 2013 Nov 10.

Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK.

The contribution of cis-regulatory mutations to human disease remains poorly understood. Whole-genome sequencing can identify all noncoding variants, yet the discrimination of causal regulatory mutations represents a formidable challenge. We used epigenomic annotation in human embryonic stem cell (hESC)-derived pancreatic progenitor cells to guide the interpretation of whole-genome sequences from individuals with isolated pancreatic agenesis. This analysis uncovered six different recessive mutations in a previously uncharacterized ~400-bp sequence located 25 kb downstream of PTF1A (encoding pancreas-specific transcription factor 1a) in ten families with pancreatic agenesis. We show that this region acts as a developmental enhancer of PTF1A and that the mutations abolish enhancer activity. These mutations are the most common cause of isolated pancreatic agenesis. Integrating genome sequencing and epigenomic annotation in a disease-relevant cell type can thus uncover new noncoding elements underlying human development and disease.
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http://dx.doi.org/10.1038/ng.2826DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4131753PMC
January 2014

A rare SNP in pre-miR-34a is associated with increased levels of miR-34a in pancreatic beta cells.

Acta Diabetol 2014 Apr 5;51(2):325-9. Epub 2013 Jul 5.

Institute of Biomedical and Clinical Science, University of Exeter Medical School, Barrack Road, Exeter, EX2 5DW, UK.

Changes in the levels of specific microRNAs (miRNAs) can reduce glucose-stimulated insulin secretion and increase beta-cell apoptosis, two causes of islet dysfunction and progression to type 2 diabetes. Studies have shown that single nucleotide polymorphisms (SNPs) within miRNA genes can affect their expression. We sought to determine whether miRNAs, with a known role in beta-cell function, possess SNPs within the pre-miRNA structure which can affect their expression. Using published literature and dbSNP, we aimed to identify miRNAs with a role in beta-cell function that also possess SNPs within the region encoding its pre-miRNA. Following transfection of plasmids, encoding the pre-miRNA and each allele of the SNP, miRNA expression was measured. Two rare SNPs located within the pre-miRNA structure of two miRNA genes important to beta-cell function (miR-34a and miR-96) were identified. Transfection of INS-1 and MIN6 cells with plasmids encoding pre-miR-34a and the minor allele of rs72631823 resulted in significantly (p < 0.05) higher miR-34a expression, compared to cells transfected with plasmids encoding the corresponding major allele. Similarly, higher levels were also observed upon transfection of HeLa cells. Transfection of MIN6 cells with plasmids encoding pre-miR-96 and each allele of rs41274239 resulted in no significant differences in miR-96 expression. A rare SNP in pre-miR-34a is associated with increased levels of mature miR-34a. Given that small changes in miR-34a levels have been shown to cause increased levels of beta-cell apoptosis this finding may be of interest to studies looking at determining the effect of rare variants on type 2 diabetes susceptibility.
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http://dx.doi.org/10.1007/s00592-013-0499-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3969511PMC
April 2014
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