PubMed | University of Bristol, Alder Hey Childrens Hospital, Bristol Genetics Laboratory and King's College London
Type: | Journal: Journal of the American Society of Nephrology : JASN | Year: 2016
Steroid-resistant nephrotic syndrome (SRNS), a heterogeneous disorder of the renal glomerular filtration barrier, results in impairment of glomerular permselectivity. Inheritance of genetic SRNS may be autosomal dominant or recessive, with a subset of autosomal recessive SRNS presenting as congenital nephrotic syndrome (CNS). Mutations in 53 genes are associated with human SRNS, but these mutations explain 30% of patients with hereditary cases and only 20% of patients with sporadic cases. The proteins encoded by these genes are expressed in podocytes, and malfunction of these proteins leads to a universal end point of podocyte injury, glomerular filtration barrier disruption, and SRNS. Here, we identified novel disease-causing mutations in membrane-associated guanylate kinase, WW, and PDZ domain-containing 2 (MAGI2) through whole-exome sequencing of a deeply phenotyped cohort of patients with congenital, childhood-onset SRNS. Although MAGI2 has been shown to interact with nephrin and regulate podocyte cytoskeleton and slit diaphragm dynamics, MAGI2 mutations have not been described in human SRNS. We detected two unique frameshift mutations and one duplication in three patients (two families); two siblings shared the same homozygous frameshift mutation, whereas one individual with sporadic SRNS exhibited compound heterozygosity. Two mutations were predicted to introduce premature stop codons, and one was predicted to result in read through of the normal translational termination codon. Immunohistochemistry in kidney sections from these patients revealed that mutations resulted in lack of or diminished podocyte MAGI2 expression. Our data support the finding that mutations in the MAGI2 gene are causal for congenital SRNS.
PubMed | Belfast City Hospital, University of Edinburgh, James Cook University, Auckland Hospital and 13 more.
Type: Journal Article | Journal: American journal of medical genetics. Part A | Year: 2016
KBG syndrome is characterized by short stature, distinctive facial features, and developmental/cognitive delay and is caused by mutations in ANKRD11, one of the ankyrin repeat-containing cofactors. We describe 32 KBG patients aged 2-47 years from 27 families ascertained via two pathways: targeted ANKRD11 sequencing (TS) in a group who had a clinical diagnosis of KBG and whole exome sequencing (ES) in a second group in whom the diagnosis was unknown. Speech delay and learning difficulties were almost universal and variable behavioral problems frequent. Macrodontia of permanent upper central incisors was seen in 85%. Other clinical features included short stature, conductive hearing loss, recurrent middle ear infection, palatal abnormalities, and feeding difficulties. We recognized a new feature of a wide anterior fontanelle with delayed closure in 22%. The subtle facial features of KBG syndrome were recognizable in half the patients. We identified 20 ANKRD11 mutations (18 novel: all truncating) confirmed by Sanger sequencing in 32 patients. Comparison of the two ascertainment groups demonstrated that facial/other typical features were more subtle in the ES group. There were no conclusive phenotype-genotype correlations. Our findings suggest that mutation of ANKRD11 is a common Mendelian cause of developmental delay. Affected patients may not show the characteristic KBG phenotype and the diagnosis is therefore easily missed. We propose updated diagnostic criteria/clinical recommendations for KBG syndrome and suggest that inclusion of ANKRD11 will increase the utility of gene panels designed to investigate developmental delay. 2016 The Authors. American Journal of Medical Genetics Part A Published by Wiley Periodicals, Inc.
PubMed | Roskilde University, Clinique de Genetique Oncologique Service de genetique, Poznan University of Medical Sciences, National and Kapodistrian University of Athens and 42 more.
Type: Journal Article | Journal: Leukemia | Year: 2016
Molecular monitoring of chronic myeloid leukemia patients using robust BCR-ABL1 tests standardized to the International Scale (IS) is key to proper disease management, especially when treatment cessation is considered. Most laboratories currently use a time-consuming sample exchange process with reference laboratories for IS calibration. A World Health Organization (WHO) BCR-ABL1 reference panel was developed (MR(1)-MR(4)), but access to the material is limited. In this study, we describe the development of the first cell-based secondary reference panel that is traceable to and faithfully replicates the WHO panel, with an additional MR(4.5) level. The secondary panel was calibrated to IS using digital PCR with ABL1, BCR and GUSB as reference genes and evaluated by 44 laboratories worldwide. Interestingly, we found that >40% of BCR-ABL1 assays showed signs of inadequate optimization such as poor linearity and suboptimal PCR efficiency. Nonetheless, when optimized sample inputs were used, >60% demonstrated satisfactory IS accuracy, precision and/or MR(4.5) sensitivity, and 58% obtained IS conversion factors from the secondary reference concordant with their current values. Correlation analysis indicated no significant alterations in %BCR-ABL1 results caused by different assay configurations. More assays achieved good precision and/or sensitivity than IS accuracy, indicating the need for better IS calibration mechanisms.
Moorman A.V.,Northumbria University |
Enshaei A.,Northumbria University |
Schwab C.,Northumbria University |
Wade R.,University of Oxford |
And 9 more authors.
Blood | Year: 2014
Recent genomic studies have provided a refined genetic map of acute lymphoblastic leukemia (ALL) and increased the number of potential prognosticmarkers. Therefore, we integrated copy-number alteration data from the 8 most commonly deleted genes, subordinately, with established chromosomal abnormalities to derive a 2-tier genetic classification. The classification was developed using 809 ALL97/99 patients and validated using 742 United Kingdom (UK) ALL2003 patients. Good-risk (GR) genetic features included ETV6-RUNX1, high hyperdiploidy, normal copy-number status for all 8 genes, isolated deletions affecting ETV6/PAX5/BTG1, and ETV6 deletions with a single additional deletion of BTG1/PAX5/CDKN2A/B. All other genetic features were classified as poor risk (PR). Three-quarters of UKALL2003 patients had a GR genetic profile and a significantly improved event-free survival (EFS) (94%) compared with patients with a PR genetic profile (79%). This difference was driven by a lower relapse rate (4% vs 17%), was seen across all patient subgroups, and was independent of other risk factors. Even genetic GR patients with minimal residual disease (>0.01%) at day 29 had an EFS in excess of 90%. In conclusion, the integration of genomic and cytogenetic data defines 2 subgroups with distinct responses to treatment and identifies a large subset of children suitable for treatment deintensification. © 2014 by The American Society of Hematology.
PubMed | Sheffield Childrens Hospital, Great Ormond Street Hospital, John Radcliffe Hospital, Northumbria University and 3 more.
Type: Journal Article | Journal: Blood | Year: 2014
Recent genomic studies have provided a refined genetic map of acute lymphoblastic leukemia (ALL) and increased the number of potential prognostic markers. Therefore, we integrated copy-number alteration data from the 8 most commonly deleted genes, subordinately, with established chromosomal abnormalities to derive a 2-tier genetic classification. The classification was developed using 809 ALL97/99 patients and validated using 742 United Kingdom (UK)ALL2003 patients. Good-risk (GR) genetic features included ETV6-RUNX1, high hyperdiploidy, normal copy-number status for all 8 genes, isolated deletions affecting ETV6/PAX5/BTG1, and ETV6 deletions with a single additional deletion of BTG1/PAX5/CDKN2A/B. All other genetic features were classified as poor risk (PR). Three-quarters of UKALL2003 patients had a GR genetic profile and a significantly improved event-free survival (EFS) (94%) compared with patients with a PR genetic profile (79%). This difference was driven by a lower relapse rate (4% vs 17%), was seen across all patient subgroups, and was independent of other risk factors. Even genetic GR patients with minimal residual disease (>0.01%) at day 29 had an EFS in excess of 90%. In conclusion, the integration of genomic and cytogenetic data defines 2 subgroups with distinct responses to treatment and identifies a large subset of children suitable for treatment deintensification.
Attilakos G.,University of Bristol |
Maddocks D.G.,University of the West of England |
Davies T.,Bristol Genetics Laboratory |
Hunt L.P.,University of Bristol |
And 3 more authors.
Prenatal Diagnosis | Year: 2011
Objective: Free fetal DNA (ffDNA) in the maternal plasma appears to originate mainly from the trophoblast. We tested the hypothesis that ffDNA concentration is increased in multiple pregnancies where trophoblastic mass has been shown to be increased. Methods: Quantitative real-time PCR was used to measure the plasma concentration of DYS14 in singleton and twin pregnancies with one or two male fetuses. Royston and Wright's regression method was used to relate ffDNA to gestational age in singleton controls; z-scores were calculated for the multiple pregnancy subgroups. Results: Fifty-five singleton and 65 twin pregnancies (36 with one and 29 with two male fetuses) were analysed. There was significantly higher ffDNA concentration in twin pregnancies with two male fetuses compared with pregnancies with one male fetus. In cases with two male fetuses, there was no statistically significant difference between monochorionic and dichorionic pregnancies. Conclusions: There is higher ffDNA concentration in multiple pregnancies, and this must be taken into account for future quantitative ffDNA applications. © 2011 John Wiley & Sons, Ltd.
Bowron A.,University of Bristol |
Honeychurch J.,Bristol Genetics Laboratory |
Williams M.,Bristol Genetics Laboratory |
Tsai-Goodman B.,University of Bristol |
And 7 more authors.
Journal of Inherited Metabolic Disease | Year: 2015
Barth syndrome (BTHS) is an X-linked disorder characterised by cardiac and skeletal myopathy, growth delay, neutropenia and 3-methylglutaconic aciduria (3-MGCA). Patients have TAZ gene mutations which affect metabolism of cardiolipin, resulting in low tetralinoleoyl cardiolipin (CL4), an increase in its precursor, monolysocardiolipin (MLCL), and an increased MLCL/CL4 ratio. During development of a diagnostic service for BTHS, leukocyte CL4 was measured in 156 controls and 34 patients with genetically confirmed BTHS. A sub-group of seven subjects from three unrelated families was identified with leukocyte CL4 concentrations within the control range. This had led to initial false negative disease detection in two of these patients. MLCL/CL4 in this subgroup was lower than in other BTHS patients but higher than controls, with no overlap between the groups. TAZ gene mutations in these families are all predicted to be pathological. This report describes the clinical histories of these seven individuals with an atypical phenotype: some features were typical of BTHS (five have had cardiomyopathy, one family has a history of male infant deaths, three have growth delay and five have 3-MGCA) but none has persistent neutropenia, five have excellent exercise tolerance and two adults are asymptomatic. This report also emphasises the importance of measurement of MLCL/CL4 ratio rather than CL4 alone in the biochemical diagnosis of the BTHS. © 2014, The Author(s).