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1. Gain and loss of TASK3 channel function and its regulation by novel variation cause KCNK9 imprinting syndrome

Author

Margot A. Cousin, Emma L. Veale, Nikita R. Dsouza, Swarnendu Tripathi, Robyn G. Holden, Maria Arelin, Geoffrey Beek, Mir Reza Bekheirnia, Jasmin Beygo, Vikas Bhambhani, Martin Bialer, Stefania Bigoni, Cyrus Boelman, Jenny Carmichael, Thomas Courtin, Benjamin Cogne, Ivana Dabaj, Diane Doummar, Laura Fazilleau, Alessandra Ferlini, Ralitza H. Gavrilova, John M. Graham, Tobias B. Haack, Jane Juusola, Sarina G. Kant, Saima Kayani, Boris Keren, Petra Ketteler, Chiara Klöckner, Tamara T. Koopmann, Teresa M. Kruisselbrink, Alma Kuechler, Laëtitia Lambert, Xénia Latypova, Robert Roger Lebel, Magalie S. Leduc, Emanuela Leonardi, Andrea M. Lewis, Wendy Liew, Keren Machol, Samir Mardini, Kirsty McWalter, Cyril Mignot, Julie McLaughlin, Alessandra Murgia, Vinodh Narayanan, Caroline Nava, Sonja Neuser, Mathilde Nizon, Davide Ognibene, Joohyun Park, Konrad Platzer, Céline Poirsier, Maximilian Radtke, Keri Ramsey, Cassandra K. Runke, Maria J. Guillen Sacoto, Fernando Scaglia, Marwan Shinawi, Stephanie Spranger, Ee Shien Tan, John Taylor, Anne-Sophie Trentesaux, Filippo Vairo, Rebecca Willaert, Neda Zadeh, Raul Urrutia, Dusica Babovic-Vuksanovic, Michael T. Zimmermann, Alistair Mathie, and Eric W. Klee

Subjects
KCNK9 imprinting syndrome, TASK3 channel, Neurodevelopmental disorder, Electrophysiology, Computational protein modeling, Medicine, Genetics, QH426-470
Abstract

Abstract Background Genomics enables individualized diagnosis and treatment, but large challenges remain to functionally interpret rare variants. To date, only one causative variant has been described for KCNK9 imprinting syndrome (KIS). The genotypic and phenotypic spectrum of KIS has yet to be described and the precise mechanism of disease fully understood. Methods This study discovers mechanisms underlying KCNK9 imprinting syndrome (KIS) by describing 15 novel KCNK9 alterations from 47 KIS-affected individuals. We use clinical genetics and computer-assisted facial phenotyping to describe the phenotypic spectrum of KIS. We then interrogate the functional effects of the variants in the encoded TASK3 channel using sequence-based analysis, 3D molecular mechanic and dynamic protein modeling, and in vitro electrophysiological and functional methodologies. Results We describe the broader genetic and phenotypic variability for KIS in a cohort of individuals identifying an additional mutational hotspot at p.Arg131 and demonstrating the common features of this neurodevelopmental disorder to include motor and speech delay, intellectual disability, early feeding difficulties, muscular hypotonia, behavioral abnormalities, and dysmorphic features. The computational protein modeling and in vitro electrophysiological studies discover variability of the impact of KCNK9 variants on TASK3 channel function identifying variants causing gain and others causing loss of conductance. The most consistent functional impact of KCNK9 genetic variants, however, was altered channel regulation. Conclusions This study extends our understanding of KIS mechanisms demonstrating its complex etiology including gain and loss of channel function and consistent loss of channel regulation. These data are rapidly applicable to diagnostic strategies, as KIS is not identifiable from clinical features alone and thus should be molecularly diagnosed. Furthermore, our data suggests unique therapeutic strategies may be needed to address the specific functional consequences of KCNK9 variation on channel function and regulation.

Published
2022
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2. <scp>POU3F3</scp> ‐related disorder: Defining the phenotype and expanding the molecular spectrum

Author

Alessandra Rossi, Lot Snijders Blok, Sonja Neuser, Chiara Klöckner, Konrad Platzer, Laurence Olivier Faivre, Heike Weigand, Maria L. Dentici, Marco Tartaglia, Marcello Niceta, Paolo Alfieri, Siddharth Srivastava, David Coulter, Lacey Smith, Kristin Vinorum, Gerarda Cappuccio, Nicola Brunetti‐Pierri, Deniz Torun, Mutluay Arslan, Mathilde F. Lauridsen, Oliver Murch, Rachel Irving, Sally A. Lynch, Sarju G. Mehta, Jenny Carmichael, Evelien Zonneveld‐Huijssoon, Bert de Vries, Tjitske Kleefstra, Katrine M. Johannesen, Ian T. Westphall, Susan S. Hughes, Sarah Smithson, Julie Evans, Tracy Dudding‐Byth, Marleen Simon, Ellen van Binsbergen, Johanna C. Herkert, Gea Beunders, Henry Oppermann, Mert Bakal, Rikke S. Møller, Guido Rubboli, and Allan Bayat

Subjects
Genetics, Genetics (clinical)
Published
2023
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3. Biallelic Mutation of ARHGEF18, Involved in the Determination of Epithelial Apicobasal Polarity, Causes Adult-Onset Retinal Degeneration

Author

Gavin Arno, Keren J. Carss, Sarah Hull, Ceniz Zihni, Anthony G. Robson, Alessia Fiorentino, Alison J. Hardcastle, Graham E. Holder, Michael E. Cheetham, Vincent Plagnol, Anthony T. Moore, F. Lucy Raymond, Karl Matter, Maria S. Balda, Andrew R. Webster, Graeme Black, Georgina Hall, Stuart Ingram, Rachel Gillespie, Forbes Manson, Panagiotis Sergouniotis, Chris Inglehearn, Carmel Toomes, Manir Ali, Martin McKibbin, James Poulter, Kamron Khan, Emma Lord, Andrea Nemeth, Susan Downes, Stephanie Halford, Jing Yu, Stefano Lise, Nikos Ponitkos, Michel Michaelides, Veronica van Heyningen, Timothy Aitman, Hana Alachkar, Sonia Ali, Louise Allen, David Allsup, Gautum Ambegaonkar, Julie Anderson, Richard Antrobus, Ruth Armstrong, Gururaj Arumugakani, Sofie Ashford, William Astle, Antony Attwood, Steve Austin, Chiara Bacchelli, Tamam Bakchoul, Tadbir K. Bariana, Helen Baxendale, David Bennett, Claire Bethune, Shahnaz Bibi, Maria Bitner-Glindzicz, Marta Bleda, Harm Boggard, Paula Bolton-Maggs, Claire Booth, John R. Bradley, Angie Brady, Matthew Brown, Michael Browning, Christine Bryson, Siobhan Burns, Paul Calleja, Natalie Canham, Jenny Carmichael, Keren Carss, Mark Caulfield, Elizabeth Chalmers, Anita Chandra, Patrick Chinnery, Manali Chitre, Colin Church, Emma Clement, Naomi Clements-Brod, Virginia Clowes, Gerry Coghlan, Peter Collins, Nichola Cooper, Amanda Creaser-Myers, Rosa DaCosta, Louise Daugherty, Sophie Davies, John Davis, Minka De Vries, Patrick Deegan, Sri V.V. Deevi, Charu Deshpande, Lisa Devlin, Eleanor Dewhurst, Rainer Doffinger, Natalie Dormand, Elizabeth Drewe, David Edgar, William Egner, Wendy N. Erber, Marie Erwood, Tamara Everington, Remi Favier, Helen Firth, Debra Fletcher, Frances Flinter, James C. Fox, Amy Frary, Kathleen Freson, Bruce Furie, Abigail Furnell, Daniel Gale, Alice Gardham, Michael Gattens, Neeti Ghali, Pavandeep K. Ghataorhe, Rohit Ghurye, Simon Gibbs, Kimberley Gilmour, Paul Gissen, Sarah Goddard, Keith Gomez, Pavel Gordins, Stefan Gräf, Daniel Greene, Alan Greenhalgh, Andreas Greinacher, Sofia Grigoriadou, Detelina Grozeva, Scott Hackett, Charaka Hadinnapola, Rosie Hague, Matthias Haimel, Csaba Halmagyi, Tracey Hammerton, Daniel Hart, Grant Hayman, Johan W.M. Heemskerk, Robert Henderson, Anke Hensiek, Yvonne Henskens, Archana Herwadkar, Simon Holden, Muriel Holder, Susan Holder, Fengyuan Hu, Aarnoud Huissoon, Marc Humbert, Jane Hurst, Roger James, Stephen Jolles, Dragana Josifova, Rashid Kazmi, David Keeling, Peter Kelleher, Anne M. Kelly, Fiona Kennedy, David Kiely, Nathalie Kingston, Ania Koziell, Deepa Krishnakumar, Taco W. Kuijpers, Dinakantha Kumararatne, Manju Kurian, Michael A. Laffan, Michele P. Lambert, Hana Lango Allen, Allan Lawrie, Sara Lear, Melissa Lees, Claire Lentaigne, Ri Liesner, Rachel Linger, Hilary Longhurst, Lorena Lorenzo, Rajiv Machado, Rob Mackenzie, Robert MacLaren, Eamonn Maher, Jesmeen Maimaris, Sarah Mangles, Ania Manson, Rutendo Mapeta, Hugh S. Markus, Jennifer Martin, Larahmie Masati, Mary Mathias, Vera Matser, Anna Maw, Elizabeth McDermott, Coleen McJannet, Stuart Meacham, Sharon Meehan, Karyn Megy, Sarju Mehta, Carolyn M. Millar, Shahin Moledina, Anthony Moore, Nicholas Morrell, Andrew Mumford, Sai Murng, Elaine Murphy, Sergey Nejentsev, Sadia Noorani, Paquita Nurden, Eric Oksenhendler, Willem H. Ouwehand, Sofia Papadia, Soo-Mi Park, Alasdair Parker, John Pasi, Chris Patch, Joan Paterson, Jeanette Payne, Andrew Peacock, Kathelijne Peerlinck, Christopher J. Penkett, Joanna Pepke-Zaba, David J. Perry, Val Pollock, Gary Polwarth, Mark Ponsford, Waseem Qasim, Isabella Quinti, Stuart Rankin, Julia Rankin, Karola Rehnstrom, Evan Reid, Christopher J. Rhodes, Michael Richards, Sylvia Richardson, Alex Richter, Irene Roberts, Matthew Rondina, Elisabeth Rosser, Catherine Roughley, Kevin Rue-Albrecht, Crina Samarghitean, Alba Sanchis-Juan, Richard Sandford, Saikat Santra, Ravishankar Sargur, Sinisa Savic, Sol Schulman, Harald Schulze, Richard Scott, Marie Scully, Suranjith Seneviratne, Carrock Sewell, Olga Shamardina, Debbie Shipley, Ilenia Simeoni, Suthesh Sivapalaratnam, Kenneth Smith, Aman Sohal, Laura Southgate, Simon Staines, Emily Staples, Hans Stauss, Penelope Stein, Jonathan Stephens, Kathleen Stirrups, Sophie Stock, Jay Suntharalingam, R. Campbell Tait, Kate Talks, Yvonne Tan, Jecko Thachil, James Thaventhiran, Ellen Thomas, Moira Thomas, Dorothy Thompson, Adrian Thrasher, Marc Tischkowitz, Catherine Titterton, Cheng-Hock Toh, Mark Toshner, Carmen Treacy, Richard Trembath, Salih Tuna, Wojciech Turek, Ernest Turro, Chris Van Geet, Marijke Veltman, Julie Vogt, Julie von Ziegenweldt, Anton Vonk Noordegraaf, Emma Wakeling, Ivy Wanjiku, Timothy Q. Warner, Evangeline Wassmer, Hugh Watkins, Andrew Webster, Steve Welch, Sarah Westbury, John Wharton, Deborah Whitehorn, Martin Wilkins, Lisa Willcocks, Catherine Williamson, Geoffrey Woods, John Wort, Nigel Yeatman, Patrick Yong, Tim Young, Ping Yu, Pediatric surgery, Molecular cell biology and Immunology, Pulmonary medicine, ACS - Pulmonary hypertension & thrombosis, APH - Quality of Care, Amsterdam Reproduction & Development (AR&D), RS: CARIM - R1.04 - Clinical thrombosis and haemostasis, MUMC+: DA CDL Algemeen (9), and Med Microbiol, Infect Dis & Infect Prev

Subjects
Male, 0301 basic medicine, Retinal degeneration, Biallelic Mutation, RHOA, PROTEIN, Eye, Medical and Health Sciences, ACTIVATION, chemistry.chemical_compound, 0302 clinical medicine, 2.1 Biological and endogenous factors, Missense mutation, Exome, Aetiology, Genetics (clinical), Genetics & Heredity, Genetics, biology, Retinal Degeneration, Cell Polarity, MOSAIC EYES, Biological Sciences, Middle Aged, Phenotype, inherited retinal dystrophy, Pedigree, UK Inherited Retinal Disease Consortium, Female, apicobasal polarity, Retinal Dystrophies, Adult, NIHR Bioresource - Rare Diseases Consortium, ARHGEF18, Genotype, Mutation, Missense, Nerve Tissue Proteins, Retina, 03 medical and health sciences, Rare Diseases, retinitis pigmentosa, Report, CRB1, Retinitis pigmentosa, medicine, Humans, Amino Acid Sequence, Eye Proteins, Eye Disease and Disorders of Vision, Alleles, Human Genome, Neurosciences, Genetic Variation, Membrane Proteins, Epithelial Cells, Retinal, CELL FEATURES, medicine.disease, NUCLEOTIDE EXCHANGE FACTOR, p114RhoGEF, 030104 developmental biology, INTEGRATIVE GENOMICS VIEWER, OKO-MEDUZY, chemistry, Mutation, MORPHOGENESIS, 030221 ophthalmology & optometry, biology.protein, Missense, rhoA GTP-Binding Protein, Rho Guanine Nucleotide Exchange Factors, Genome-Wide Association Study
Abstract

Mutations in more than 250 genes are implicated in inherited retinal dystrophy; the encoded proteins are involved in a broad spectrum of pathways. The presence of unsolved families after highly parallel sequencing strategies suggests that further genes remain to be identified. Whole-exome and -genome sequencing studies employed here in large cohorts of affected individuals revealed biallelic mutations in ARHGEF18 in three such individuals. ARHGEF18 encodes ARHGEF18, a guanine nucleotide exchange factor that activates RHOA, a small GTPase protein that is a key component of tight junctions and adherens junctions. This biological pathway is known to be important for retinal development and function, as mutation of CRB1, encoding another component, causes retinal dystrophy. The retinal structure in individuals with ARHGEF18 mutations resembled that seen in subjects with CRB1 mutations. Five mutations were found on six alleles in the three individuals: c.808A>G (p.Thr270Ala), c.1617+5G>A (p.Asp540Glyfs ∗ 63), c.1996C>T (p.Arg666 ∗ ), c.2632G>T (p.Glu878 ∗ ), and c.2738_2761del (p.Arg913_Glu920del). Functional tests suggest that each disease genotype might retain some ARHGEF18 activity, such that the phenotype described here is not the consequence of nullizygosity. In particular, the p.Thr270Ala missense variant affects a highly conserved residue in the DBL homology domain, which is required for the interaction and activation of RHOA. Previously, knock-out of Arhgef18 in the medaka fish has been shown to cause larval lethality which is preceded by retinal defects that resemble those seen in zebrafish Crumbs complex knock-outs. The findings described here emphasize the peculiar sensitivity of the retina to perturbations of this pathway, which is highlighted as a target for potential therapeutic strategies.

Published
2017
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4. Comprehensive Rare Variant Analysis via Whole-Genome Sequencing to Determine the Molecular Pathology of Inherited Retinal Disease

Author

Keren J. Carss, Gavin Arno, Marie Erwood, Jonathan Stephens, Alba Sanchis-Juan, Sarah Hull, Karyn Megy, Detelina Grozeva, Eleanor Dewhurst, Samantha Malka, Vincent Plagnol, Christopher Penkett, Kathleen Stirrups, Roberta Rizzo, Genevieve Wright, Dragana Josifova, Maria Bitner-Glindzicz, Richard H. Scott, Emma Clement, Louise Allen, Ruth Armstrong, Angela F. Brady, Jenny Carmichael, Manali Chitre, Robert H.H. Henderson, Jane Hurst, Robert E. MacLaren, Elaine Murphy, Joan Paterson, Elisabeth Rosser, Dorothy A. Thompson, Emma Wakeling, Willem H. Ouwehand, Michel Michaelides, Anthony T. Moore, Andrew R. Webster, F. Lucy Raymond, Timothy Aitman, Hana Alachkar, Sonia Ali, David Allsup, Gautum Ambegaonkar, Julie Anderson, Richard Antrobus, Gururaj Arumugakani, Sofie Ashford, William Astle, Antony Attwood, Steve Austin, Chiara Bacchelli, Tamam Bakchoul, Tadbir K. Bariana, Helen Baxendale, David Bennett, Claire Bethune, Shahnaz Bibi, Marta Bleda, Harm Boggard, Paula Bolton-Maggs, Claire Booth, John R. Bradley, Angie Brady, Matthew Brown, Michael Browning, Christine Bryson, Siobhan Burns, Paul Calleja, Natalie Canham, Keren Carss, Mark Caulfield, Elizabeth Chalmers, Anita Chandra, Patrick Chinnery, Colin Church, Naomi Clements-Brod, Virginia Clowes, Gerry Coghlan, Peter Collins, Nichola Cooper, Amanda Creaser-Myers, Rosa DaCosta, Louise Daugherty, Sophie Davies, John Davis, Minka De Vries, Patrick Deegan, Sri V.V. Deevi, Charu Deshpande, Lisa Devlin, Rainer Doffinger, Natalie Dormand, Elizabeth Drewe, David Edgar, William Egner, Wendy N. Erber, Tamara Everington, Remi Favier, Helen Firth, Debra Fletcher, Frances Flinter, James C. Fox, Amy Frary, Kathleen Freson, Bruce Furie, Abigail Furnell, Daniel Gale, Alice Gardham, Michael Gattens, Neeti Ghali, Pavandeep K. Ghataorhe, Rohit Ghurye, Simon Gibbs, Kimberley Gilmour, Paul Gissen, Sarah Goddard, Keith Gomez, Pavel Gordins, Stefan Gräf, Daniel Greene, Alan Greenhalgh, Andreas Greinacher, Sofia Grigoriadou, Scott Hackett, Charaka Hadinnapola, Rosie Hague, Matthias Haimel, Csaba Halmagyi, Tracey Hammerton, Daniel Hart, Grant Hayman, Johan W.M. Heemskerk, Robert Henderson, Anke Hensiek, Yvonne Henskens, Archana Herwadkar, Simon Holden, Muriel Holder, Susan Holder, Fengyuan Hu, Aarnoud Huissoon, Marc Humbert, Roger James, Stephen Jolles, Rashid Kazmi, David Keeling, Peter Kelleher, Anne M. Kelly, Fiona Kennedy, David Kiely, Nathalie Kingston, Ania Koziell, Deepa Krishnakumar, Taco W. Kuijpers, Dinakantha Kumararatne, Manju Kurian, Michael A. Laffan, Michele P. Lambert, Hana Lango Allen, Allan Lawrie, Sara Lear, Melissa Lees, Claire Lentaigne, Ri Liesner, Rachel Linger, Hilary Longhurst, Lorena Lorenzo, Rajiv Machado, Rob Mackenzie, Robert MacLaren, Eamonn Maher, Jesmeen Maimaris, Sarah Mangles, Ania Manson, Rutendo Mapeta, Hugh S. Markus, Jennifer Martin, Larahmie Masati, Mary Mathias, Vera Matser, Anna Maw, Elizabeth McDermott, Coleen McJannet, Stuart Meacham, Sharon Meehan, Sarju Mehta, Carolyn M. Millar, Shahin Moledina, Anthony Moore, Nicholas Morrell, Andrew Mumford, Sai Murng, Sergey Nejentsev, Sadia Noorani, Paquita Nurden, Eric Oksenhendler, Sofia Papadia, Soo-Mi Park, Alasdair Parker, John Pasi, Chris Patch, Jeanette Payne, Andrew Peacock, Kathelijne Peerlinck, Christopher J. Penkett, Joanna Pepke-Zaba, David J. Perry, Val Pollock, Gary Polwarth, Mark Ponsford, Waseem Qasim, Isabella Quinti, Stuart Rankin, Julia Rankin, Karola Rehnstrom, Evan Reid, Christopher J. Rhodes, Michael Richards, Sylvia Richardson, Alex Richter, Irene Roberts, Matthew Rondina, Catherine Roughley, Kevin Rue-Albrecht, Crina Samarghitean, Richard Sandford, Saikat Santra, Ravishankar Sargur, Sinisa Savic, Sol Schulman, Harald Schulze, Richard Scott, Marie Scully, Suranjith Seneviratne, Carrock Sewell, Olga Shamardina, Debbie Shipley, Ilenia Simeoni, Suthesh Sivapalaratnam, Kenneth Smith, Aman Sohal, Laura Southgate, Simon Staines, Emily Staples, Hans Stauss, Penelope Stein, Sophie Stock, Jay Suntharalingam, R. Campbell Tait, Kate Talks, Yvonne Tan, Jecko Thachil, James Thaventhiran, Ellen Thomas, Moira Thomas, Dorothy Thompson, Adrian Thrasher, Marc Tischkowitz, Catherine Titterton, Cheng-Hock Toh, Mark Toshner, Carmen Treacy, Richard Trembath, Salih Tuna, Wojciech Turek, Ernest Turro, Chris Van Geet, Marijke Veltman, Julie Vogt, Julie von Ziegenweldt, Anton Vonk Noordegraaf, Ivy Wanjiku, Timothy Q. Warner, Evangeline Wassmer, Hugh Watkins, Andrew Webster, Steve Welch, Sarah Westbury, John Wharton, Deborah Whitehorn, Martin Wilkins, Lisa Willcocks, Catherine Williamson, Geoffrey Woods, John Wort, Nigel Yeatman, Patrick Yong, Tim Young, Ping Yu, Pediatric surgery, Molecular cell biology and Immunology, Pulmonary medicine, ACS - Pulmonary hypertension & thrombosis, APH - Quality of Care, Amsterdam Reproduction & Development (AR&D), Rue-Albrecht, K, RS: CARIM - R1.04 - Clinical thrombosis and haemostasis, MUMC+: DA CDL Algemeen (9), Med Microbiol, Infect Dis & Infect Prev, RS: CARIM - R1.03 - Cell biochemistry of thrombosis and haemostasis, Biochemie, Raymond, Lucy [0000-0003-2652-3355], Apollo - University of Cambridge Repository, Vascular Medicine, and Paediatric Infectious Diseases / Rheumatology / Immunology

Subjects
0301 basic medicine, Male, DNA Mutational Analysis, EXOME, PROTEIN, Eye, whole-genome sequence, NIHR-BioResource Rare Diseases Consortium, Medical and Health Sciences, Choroideremia, ACTIVATION, 0302 clinical medicine, Ethnicity, 2.1 Biological and endogenous factors, Exome, rare sequence variant, Copy-number variation, Aetiology, MUTATION, Genetics (clinical), Exome sequencing, Genetics & Heredity, Genetics, Genome, Adaptor Proteins, Biological Sciences, DYSTROPHY, copy-number variants, Female, Human, Common disease-common variant, LEBER CONGENITAL AMAUROSIS, Ethnic Groups, Genes, Recessive, Biology, DIAGNOSIS, Article, 03 medical and health sciences, Rare Diseases, Retinal Diseases, STARGARDT DISEASE, Clinical Research, REVEALS, Journal Article, medicine, Recessive, Humans, retinal dystrophy, Eye Disease and Disorders of Vision, Alleles, Adaptor Proteins, Signal Transducing, Whole genome sequencing, Base Sequence, Genome, Human, Human Genome, Signal Transducing, Neurosciences, Genetic Variation, medicine.disease, GENE, Introns, Stargardt disease, Good Health and Well Being, 030104 developmental biology, Genes, Mutation, 030221 ophthalmology & optometry, Human genome
Abstract

Inherited retinal disease is a common cause of visual impairment and represents a highly heterogeneous group of conditions. Here, we present findings from a cohort of 722 individuals with inherited retinal disease, who have had whole-genome sequencing (n = 605), whole-exome sequencing (n = 72), or both (n = 45) performed, as part of the NIHR-BioResource Rare Diseases research study. We identified pathogenic variants (single-nucleotide variants, indels, or structural variants) for 404/722 (56%) individuals. Whole-genome sequencing gives unprecedented power to detect three categories of pathogenic variants in particular: structural variants, variants in GC-rich regions, which have significantly improved coverage compared to whole-exome sequencing, and variants in non-coding regulatory regions. In addition to previously reported pathogenic regulatory variants, we have identified a previously unreported pathogenic intronic variant in $\textit{CHM}$ in two males with choroideremia. We have also identified 19 genes not previously known to be associated with inherited retinal disease, which harbor biallelic predicted protein-truncating variants in unsolved cases. Whole-genome sequencing is an increasingly important comprehensive method with which to investigate the genetic causes of inherited retinal disease.

Published
2017
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5. Indiscernibles and Plato’s Forms vs. Parmenides

Author

Jenny Carmichael

Subjects
Contemporary philosophy, Philosophy, Indiscernibles, Zeno's paradoxes, Epistemology
Abstract

In Parmenides, the young Socrates defends several candidate forms against Parmenides, who makes five objections: the objection of forms of common things, the question of the part vs. the whole, the third man argument, infinite regress, and the greatest difficulty problem. I define forms in terms of Leibniz’s Principle of the Identity of Indiscernibles (PII) in an attempt to overcome Parmenides’ opposition. I show that the main force in Parmenides’ objections consists of absurdities that emerge in relations between forms and particulars: absurdities that are avoided if the form and its instantiation in the particular are identical.

Published
2013
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6. Site-Specific Conjugation of Monodispersed DOTA-PEGn to a Thiolated Diabody Reveals the Effect of Increasing PEG Size on Kidney Clearance and Tumor Uptake with Improved 64-Copper PET Imaging

Author

Peter J. Hudson, Fabio Turatti, John E. Shively, Erasmus Poku, Lin Li, Anne-Line Anderson, David Tai Leong, Michael Paul Wheatcroft, Desiree Crow, David Colcher, James R. Bading, Jenny Carmichael, Andrew Raubitschek, and Paul J. Yazaki

Subjects
Biomedical Engineering, Mice, Nude, Pharmaceutical Science, chemistry.chemical_element, Bioengineering, Conjugated system, Kidney, Article, Polyethylene Glycols, Heterocyclic Compounds, 1-Ring, Mice, chemistry.chemical_compound, Neoplasms, PEG ratio, medicine, Animals, DOTA, Tissue Distribution, Sulfhydryl Compounds, Binding site, Pharmacology, Binding Sites, Molecular Structure, biology, Chemistry, Organic Chemistry, Copper, medicine.anatomical_structure, Copper Radioisotopes, Biochemistry, Positron-Emission Tomography, biology.protein, Biophysics, Female, Radiopharmaceuticals, Antibody, Neoplasm Transplantation, Biotechnology, Conjugate
Abstract

Optimal PET imaging of tumors with radiolabeled engineered antibodies requires, among other parameters, matching blood clearance and tumor uptake with the half-life of the engineered antibody. Although diabodies have favorable molecular sizes (50 kDa) for rapid blood clearance (t(1/2) = 30-60 min) and are bivalent, thereby increasing tumor uptake, they exhibit substantial kidney uptake as their major route of clearance, which is especially evident when they are labeled with the PET isotope (64)Cu (t(1/2) = 12 h). To overcome this drawback, diabodies may be conjugated to PEG, a modification that increases the apparent molecular size of the diabody and reduces kidney uptake without adversely affecting tumor uptake or the tumor to blood ratio. We show here that site-specific attachment of monodispersed PEGn of increasing molecular size (n = 12, 24, and 48) can uniformly increase the apparent molecular size of the PEG-diabody conjugate, decrease kidney uptake, and increase tumor uptake, the latter due to the increased residence time of the conjugate in the blood. Since the monodispersed PEGs were preconjugated to the chelator DOTA, the conjugates were able to bind radiometals such as (111)In and (64)Cu that can be used for SPECT and PET imaging, respectively. To allow conjugation of the DOTA-PEG to the diabody, the DOTA-PEG incorporated a terminal cysteine conjugated to a vinyl sulfone moiety. In order to control the conjugation chemistry, we have engineered a surface thiolated diabody that incorporates two cysteines per monomer (four per diabody). The thiolated diabody was expressed and purified from bacterial fermentation and only needs to be reduced prior to conjugation to the DOTA-PEGn-Cys-VS. This novel imaging agent (a diabody with DOTA-PEG48-Cys-VS attached to introduced thiols) gave up to 80%ID/g of tumor uptake with a tumor to blood ratio (T/B) of 8 at 24 h when radiolabeled with (111)In and 37.9% ID/g of tumor uptake (T/B = 8) at 44 h when radiolabeled with (64)Cu in PET imaging in an animal model. Tumor uptake was significantly improved from the 50% ID/g at 24 h observed with diabodies that were pegylated on surface lysine residues. Importantly, there was no loss of immunoreactivity of the site-specific Cys-conjugated diabody to its antigen (TAG-72) compared to the parent, unconjugated diabody. We propose that thiolated diabodies conjugated to DOTAylated monodisperse PEGs have the potential for superior SPECT and PET imaging in a clinical setting.

Published
2011
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7. Genetic defects of human brain development

Author

Christopher Geoffrey Woods and Jenny Carmichael

Subjects
Human Development, General Neuroscience, Neuronal migration, Brain, Lissencephaly, Human brain, Biology, Nervous System Malformations, medicine.disease, medicine.anatomical_structure, Genetic etiology, medicine, Humans, Neurology (clinical), Neuroscience
Abstract

This review focuses on malformations of the central nervous system that have a genetic etiology. One can view each malformation as giving us unique details on a map entitled "how to make a human brain." The gene(s) that cause each malformation are being identified, allowing discovery of their specific role in neurodevelopment, and defining a "road" on the map. The malformation is then the developmental consequence of "taking a wrong turn." Assimilation of complementary data from other species with human malformation phenotype and genotype is revealing just how wonderful and complex the neurodevelopment map is. Here we highlight recent research on brain malformations and how this is illuminating the map of normal human brain formation.

Published
2006
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8. Heat shock protein 27 prevents cellular polyglutamine toxicity and suppresses the increase of reactive oxygen species caused by huntingtin

Author

Jenny Carmichael, Chantal Diaz-Latoud, Olivier Sauvageot, Andreas Wyttenbach, David C. Rubinsztein, and Andre-Patrik Arrigo

Subjects
Programmed cell death, Huntingtin, Cell Survival, Blotting, Western, Green Fluorescent Proteins, Cytochrome c Group, Nerve Tissue Proteins, Biology, Mitochondrion, Protein aggregation, Transfection, Immunoenzyme Techniques, Hsp27, Cricetinae, Heat shock protein, Genetics, Huntingtin Protein, Animals, Humans, Enzyme Inhibitors, Phosphorylation, Molecular Biology, Heat-Shock Proteins, Genetics (clinical), Nuclear Proteins, Haplorhini, General Medicine, Caspase Inhibitors, Glutathione, Up-Regulation, Cell biology, Luminescent Proteins, Biochemistry, COS Cells, Mutation, biology.protein, Peptides, Reactive Oxygen Species, Intracellular, Protein Binding
Abstract

Neuronal loss and intraneuronal protein aggregates are characteristics of Huntington's disease (HD), which is one of 10 known neurodegenerative disorders caused by an expanded polyglutamine [poly(Q)] tract in the disease protein. N-terminal fragments of mutant huntingtin produce intracellular aggregates and cause toxicity. Several studies have shown that chaperones suppress poly(Q) aggregation and toxicity/cell death, but the mechanisms by which they prevent poly(Q)-mediated cell death remain unclear. In the present study, we identified heat shock protein 27 (HSP27) as a suppressor of poly(Q) mediated cell death, using a cellular model of HD. In contrast to HSP40/70 chaperones, we showed that HSP27 suppressed poly(Q) death without suppressing poly(Q) aggregation. We tested the hypotheses that HSP27 may reduce poly(Q)-mediated cell death either by binding cytochrome c and inhibiting the mitochondrial death pathway or by protecting against reactive oxygen species (ROS). While poly(Q)-induced cell death was reduced by inhibiting cytochrome c (cyt c) release from mitochondria, protection by HSP27 was regulated by its phosphorylation status and was independent of its ability to bind to cyt c. However, we observed that mutant huntingtin caused increased levels of ROS in neuronal and non-neuronal cells. ROS contributed to cell death because both N-acetyl-L-cysteine and glutathione in its reduced form suppressed poly(Q)-mediated cell death. HSP27 decreased ROS in cells expressing mutant huntingtin, suggesting that this chaperone protects cells against oxidative stress. We propose that a poly(Q) mutation can induce ROS that directly contribute to cell death and that HSP27 is an antagonist of this process.

Published
2002
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9. Huntington's disease: molecular basis of neurodegeneration

Author

David C. Rubinsztein and Jenny Carmichael

Subjects
Huntingtin, Biology, Huntington's disease, Trinucleotide Repeats, medicine, Huntingtin Protein, Humans, Molecular Biology, Cell Aggregation, Neurons, Cell Death, Neurodegeneration, Neurotoxicity, Brain, Polyglutamine tract, medicine.disease, Cell aggregation, Corpus Striatum, Cell biology, Huntington Disease, Mutation, Nerve Degeneration, Molecular Medicine, Chromosomes, Human, Pair 4, Trinucleotide repeat expansion, Peptides
Abstract

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by a CAG trinucleotide repeat expansion in the HD gene. The expanded repeats are translated into an abnormally long polyglutamine tract close to the N-terminus of the HD gene product (‘huntingtin’). Studies in humans and mouse models suggest that the mutation is associated with a deleterious gain-of-function. Several studies have suggested that the large huntingtin protein is cleaved to produce a shorter N-terminal fragment containing the polyglutamine expansion, and that the polyglutamine expansion causes the protein fragment to misfold and form aggregates (inclusions) in the nuclei and processes of neurons. It is likely that neurotoxicity is caused by the misfolded protein in its soluble form, and/or in aggregates, and/or in the process of aggregation. A wide range of potential mechanisms for neurotoxicity have been proposed, including caspase activation, dysregulation of transcriptional pathways, increased production of reactive oxygen species, and inhibition of proteasome activity. In this review we consider the current status of research in the field and possible mechanisms whereby the HD mutation might result in neurodegeneration.

Published
2003

10. The bacterial chaperonin GroEL requires GroES to reduce aggregation and cell death in a COS-7 cell model of Huntington's disease

Author

Jenny Carmichael, Coralie Vacher, and David C. Rubinsztein

Subjects
congenital, hereditary, and neonatal diseases and abnormalities, Huntingtin, Mutant, Blotting, Western, Nerve Tissue Proteins, Transfection, Models, Biological, Chaperonin, Mutant protein, mental disorders, Chaperonin 10, Animals, Genetics, Inclusion Bodies, biology, Cell Death, General Neuroscience, Nuclear Proteins, GroES, Chaperonin 60, Polyglutamine tract, GroEL, Immunohistochemistry, nervous system diseases, Cell biology, Huntington Disease, Chaperone (protein), COS Cells, Mutation, biology.protein, Peptides
Abstract

Huntington's disease (HD) is caused by expansions of more than 35 CAG repeats in the HD gene. These repeats are translated into a long polyglutamine tract that confers a deleterious gain-of-function on the mutant protein. Intraneuronal inclusions comprising mutant huntingtin are found in HD patient brains. Here we show that the bacterial chaperonin GroEL can reduce aggregation of mutant huntingtin in COS-7 cells and requires GroES for efficient activity, analogous to what has been described in bacteria. The reduction in aggregation of mutant huntingtin by GroEL/GroES was associated with protection against polyglutamine-induced cell death.

Published
2002

11. Correction to 'Site-Specific Conjugation of Monodispersed DOTA-PEGn to Thiolated Diabody Reveals Effect of Increasing Peg Size on Kidney Clearance and Tumor Uptake with Improved 64-Copper PET Imaging'

Author

Lin Li, Desiree Crow, Fabio Turatti, James R. Bading, Anne-Line Anderson, Erasmus Poku, Paul J. Yazaki, Jenny Carmichael, David Leong, David Wheatcroft, Andrew A. Raubitschek, Peter J. Hudson, David Colcher, and John E. Shively

Subjects
Pharmacology, Organic Chemistry, Biomedical Engineering, Pharmaceutical Science, Bioengineering, Biotechnology
Published
2011
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13. Huntington's disease: from pathology and genetics to potential therapies.

Author

Sara Imarisio, Jenny Carmichael, Viktor Korolchuk, Chien-Wen Chen, Shinji Saiki, Claudia Rose, Gauri Krishna, Janet E. Davies, Evangelia Ttofi, Benjamin R. Underwood, and David C. Rubinsztein

Subjects
*HUNTINGTON disease, *POLYCYSTIC kidney disease, *PREVENTIVE medicine, *TOXICITY testing
Abstract

Huntington's disease (HD) is a devastating autosomal dominant neurodegenerative disease caused by a CAG trinucleotide repeat expansion encoding an abnormally long polyglutamine tract in the huntingtin protein. Much has been learnt since the mutation was identified in 1993. We review the functions of wild-type huntingtin. Mutant huntingtin may cause toxicity via a range of different mechanisms. The primary consequence of the mutation is to confer a toxic gain of function on the mutant protein and this may be modified by certain normal activities that are impaired by the mutation. It is likely that the toxicity of mutant huntingtin is revealed after a series of cleavage events leading to the production of N-terminal huntingtin fragment(s) containing the expanded polyglutamine tract. Although aggregation of the mutant protein is a hallmark of the disease, the role of aggregation is complex and the arguments for protective roles of inclusions are discussed. Mutant huntingtin may mediate some of its toxicity in the nucleus by perturbing specific transcriptional pathways. HD may also inhibit mitochondrial function and proteasome activity. Importantly, not all of the effects of mutant huntingtin may be cell-autonomous, and it is possible that abnormalities in neighbouring neurons and glia may also have an impact on connected cells. It is likely that there is still much to learn about mutant huntingtin toxicity, and important insights have already come and may still come from chemical and genetic screens. Importantly, basic biological studies in HD have led to numerous potential therapeutic strategies. [ABSTRACT FROM AUTHOR]

Published
2008
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