1
|
Aubert Mucca M, Patat O, Whalen S, Arnaud L, Barcia G, Buratti J, Cogné B, Doummar D, Karsenty C, Kenis S, Leguern E, Lesca G, Nava C, Nizon M, Piton A, Valence S, Villard L, Weckhuysen S, Keren B, Mignot C. Patients with KCNH1-related intellectual disability without distinctive features of Zimmermann-Laband/Temple-Baraitser syndrome. J Med Genet 2021; 59:505-510. [PMID: 33811134 DOI: 10.1136/jmedgenet-2020-107511] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 03/03/2021] [Accepted: 03/12/2021] [Indexed: 01/23/2023]
Abstract
De novo missense variants in KCNH1 encoding Kv10.1 are responsible for two clinically recognisable phenotypes: Temple-Baraitser syndrome (TBS) and Zimmermann-Laband syndrome (ZLS). The clinical overlap between these two syndromes suggests that they belong to a spectrum of KCNH1-related encephalopathies. Affected patients have severe intellectual disability (ID) with or without epilepsy, hypertrichosis and distinctive features such as gingival hyperplasia and nail hypoplasia/aplasia (present in 20/23 reported cases).We report a series of seven patients with ID and de novo pathogenic KCNH1 variants identified by whole-exome sequencing or an epilepsy gene panel in whom the diagnosis of TBS/ZLS had not been first considered. Four of these variants, p.(Thr294Met), p.(Ala492Asp), p.(Thr493Asn) and p.(Gly496Arg), were located in the transmembrane domains S3 and S6 of Kv10.1 and one, p.(Arg693Gln), in its C-terminal cyclic nucleotide-binding homology domain (CNBHD). Clinical reappraisal by the referring clinical geneticists confirmed the absence of the distinctive gingival and nail features of TBS/ZLS.Our study expands the phenotypical spectrum of KCNH1-related encephalopathies to individuals with an attenuated extraneurological phenotype preventing a clinical diagnosis of TBS or ZLS. This subtype may be related to recurrent substitutions of the Gly496, suggesting a genotype-phenotype correlation and, possibly, to variants in the CNBHD domain.
Collapse
Affiliation(s)
| | - Olivier Patat
- Service de Génétique Médicale, CHU Toulouse Purpan, Toulouse, France
| | - Sandra Whalen
- Unité Fonctionnelle de Génétique Clinique, Centre de Référence Anomalies du développement et syndromes malformatifs, APHP.Sorbonne Université, Hôpital Armand Trousseau, Paris, Île-de-France, France
| | - Lionel Arnaud
- APHP.Sorbonne Université, Département de Génétique, Groupe Hospitalier Pitié Salpêtrière et Hôpital Trousseau, Paris, Île-de-France, France
| | - Giulia Barcia
- APHP, Service de Génétique Médicale, Hôpital Necker-Enfants Malades, Imagine Institute, Paris Descartes University, Paris, France
| | - Julien Buratti
- APHP.Sorbonne Université, Département de Génétique, Groupe Hospitalier Pitié Salpêtrière et Hôpital Trousseau, Paris, Île-de-France, France
| | - Benjamin Cogné
- Service de Génétique Médicale, L'institut du thorax, INSERM, CNRS, UNIV Nantes, Centre Hospitalier Universitaire de Nantes, Nantes, France
| | - Diane Doummar
- Service de Neuropédiatrie - Unité de neuropédiatrie et pathologie du développement, CHU Paris Est - Hôpital d'Enfants Armand-Trousseau, Paris, France
| | - Caroline Karsenty
- Service de Neuropédiatrie, CHU Toulouse, Hôpital des Enfants, Toulouse, France
| | - Sandra Kenis
- Child Neurology Department, University of Antwerp, University Hospital Antwerp, Edegem, Antwerp, Belgium
| | - Eric Leguern
- APHP.Sorbonne Université, Département de Génétique, Groupe Hospitalier Pitié Salpêtrière et Hôpital Trousseau, Paris, Île-de-France, France
| | - Gaetan Lesca
- EuroEPINOMICS, EuroEPINOMICS, Strasbourg, France.,Service de Génétique, LBMMS, Groupement Hospitalier Est, CHU de Lyon, Lyon, France
| | - Caroline Nava
- APHP.Sorbonne Université, Département de Génétique, Groupe Hospitalier Pitié Salpêtrière et Hôpital Trousseau, Paris, Île-de-France, France
| | - Mathilde Nizon
- Service de Génétique Médicale, L'institut du thorax, INSERM, CNRS, UNIV Nantes, Centre Hospitalier Universitaire de Nantes, Nantes, France
| | - Amelie Piton
- Laboratory of Genetic Diagnosis, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Stéphanie Valence
- Service de Neuropédiatrie - Unité de neuropédiatrie et pathologie du développement, CHU Paris Est - Hôpital d'Enfants Armand-Trousseau, Paris, France
| | - Laurent Villard
- Laboratoire de génétique moléculaire, Département de Génétique Médicale, CHU de Marseille - Hôpital La Timone, Marseille, France
| | - Sarah Weckhuysen
- Applied&Translational Genomics group, VIB-Center for Molecular Neurology, University of Antwerp, Antwerp, Belgium.,Neurology Department, University Hospital Antwerp, Antwerp, Belgium
| | - Boris Keren
- APHP.Sorbonne Université, Département de Génétique, Groupe Hospitalier Pitié Salpêtrière et Hôpital Trousseau, Paris, Île-de-France, France
| | - Cyril Mignot
- APHP.Sorbonne Université, Département de Génétique, Groupe Hospitalier Pitié Salpêtrière et Hôpital Trousseau, Paris, Île-de-France, France.,INSERM, U1127, CNRS UMR 7225, Sorbonne Université, UPMC Univ Paris 06 UMR S1127, Institut du Cerveau et la Moelle épinière ICM, Paris, France.,Centre de Référence Déficiences Intellectuelles de Causes Rares, GH Pitié Salpêtrière, Paris, France
| |
Collapse
|
3
|
"Electrifying dysmorphology": Potassium channelopathies causing dysmorphic syndromes. ADVANCES IN GENETICS 2020; 105:137-174. [PMID: 32560786 DOI: 10.1016/bs.adgen.2020.03.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Potassium channels are a heterogeneous group of membrane-bound proteins, whose functions support a diverse range of biological processes. Genetic disorders arising from mutations in potassium channels are classically recognized by symptoms arising from acute channel dysfunction, such as periodic paralysis, ataxia, seizures, or cardiac conduction abnormalities, often in a patient with otherwise normal examination findings. In this chapter, we review a distinct subgroup of rare potassium channelopathies whose presentations are instead suggestive of a developmental disorder, with features including intellectual disability, craniofacial dysmorphism or other physical anomalies. Known conditions within this subgroup are: Andersen-Tawil syndrome, Birk-Barel syndrome, Cantú syndrome, Keppen-Lubinsky syndrome, Temple-Baraitser syndrome, Zimmerman-Laband syndrome and a very similar disorder called Bauer-Tartaglia or FHEIG syndrome. Ion channelopathies are unlikely to be routinely considered in the differential diagnosis of children presenting with developmental concerns, and so detailed description and photographs of the clinical phenotype are provided to aid recognition. For several of these disorders, functional characterization of the genetic mutations responsible has led to identification of candidate therapies, including drugs already commonly used for other indications, which adds further impetus to their prompt recognition. Together, these cases illustrate the potential for mechanistic insights gained from genetic diagnosis to drive translational work toward targeted, disease-modifying therapies for rare disorders.
Collapse
|
4
|
Chow CY, Absalom N, Biggs K, King GF, Ma L. Venom-derived modulators of epilepsy-related ion channels. Biochem Pharmacol 2020; 181:114043. [PMID: 32445870 DOI: 10.1016/j.bcp.2020.114043] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 05/18/2020] [Indexed: 12/18/2022]
Abstract
Epilepsy is characterised by spontaneous recurrent seizures that are caused by an imbalance between neuronal excitability and inhibition. Since ion channels play fundamental roles in the generation and propagation of action potentials as well as neurotransmitter release at a subset of excitatory and inhibitory synapses, their dysfunction has been linked to a wide variety of epilepsies. Indeed, these unique proteins are the major biological targets for antiepileptic drugs. Selective targeting of a specific ion channel subtype remains challenging for small molecules, due to the high level of homology among members of the same channel family. As a consequence, there is a growing trend to target ion channels with biologics. Venoms are the best known natural source of ion channel modulators, and venom peptides are increasingly recognised as potential therapeutics due to their high selectivity and potency gained through millions of years of evolutionary selection pressure. Here we describe the major ion channel families involved in the pathogenesis of various types of epilepsy, including voltage-gated Na+, K+, Ca2+ channels, Cys-loop receptors, ionotropic glutamate receptors and P2X receptors, and currently available venom-derived peptides that target these channel proteins. Although only a small number of venom peptides have successfully progressed to the clinic, there is reason to be optimistic about their development as antiepileptic drugs, notwithstanding the challenges associated with development of any class of peptide drug.
Collapse
Affiliation(s)
- Chun Yuen Chow
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Nathan Absalom
- Brain and Mind Centre, School of Pharmacy, Faculty of Health and Medicine, The University of Sydney, Sydney, NSW 2050, Australia
| | - Kimberley Biggs
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Linlin Ma
- Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111, Australia.
| |
Collapse
|
5
|
Mégarbané A, Al-Ali R, Choucair N, Lek M, Wang E, Ladjimi M, Rose CM, Hobeika R, Macary Y, Temanni R, Jithesh PV, Chouchane A, Sastry KS, Thomas R, Tomei S, Liu W, Marincola FM, MacArthur D, Chouchane L. Temple-Baraitser Syndrome and Zimmermann-Laband Syndrome: one clinical entity? BMC MEDICAL GENETICS 2016; 17:42. [PMID: 27282200 PMCID: PMC4901505 DOI: 10.1186/s12881-016-0304-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 06/02/2016] [Indexed: 01/07/2023]
Abstract
BACKGROUND KCNH1 encodes a voltage-gated potassium channel that is predominantly expressed in the central nervous system. Mutations in this gene were recently found to be responsible for Temple-Baraitser Syndrome (TMBTS) and Zimmermann-Laband syndrome (ZLS). METHODS Here, we report a new case of TMBTS diagnosed in a Lebanese child. Whole genome sequencing was carried out on DNA samples of the proband and his parents to identify mutations associated with this disease. Sanger sequencing was performed to confirm the presence of detected variants. RESULTS Whole genome sequencing revealed three missense mutations in TMBTS patient: c.1042G > A in KCNH1, c.2131 T > C in STK36, and c.726C > A in ZNF517. According to all predictors, mutation in KCNH1 is damaging de novo mutation that results in substitution of Glycine by Arginine, i.e., p.(Gly348Arg). This mutation was already reported in a patient with ZLS that could affect the connecting loop between helices S4-S5 of KCNH1 with a gain of function effect. CONCLUSIONS Our findings demonstrate that KCNH1 mutations cause TMBTS and expand the mutational spectrum of KCNH1 in TMBTS. In addition, all cases of TMBTS were reviewed and compared to ZLS. We suggest that the two syndromes are a continuum and that the variability in the phenotypes is the result of the involvement of genetic modifiers.
Collapse
Affiliation(s)
| | - Rashid Al-Ali
- Bioinformatics Division, Sidra Medical & Research Center, Doha, Qatar
| | | | - Monko Lek
- Medical and Population Genetics, Broad Institute of Harvard Medical School, Boston, USA
| | - Ena Wang
- Genomics Core Laboratory, Translational Medicine Division, Sidra Medical & Research Center, Doha, Qatar
| | - Moncef Ladjimi
- Laboratory of Protein Chemistry, Weill Cornell Medicine-Qatar, Doha, Qatar
| | - Catherine M Rose
- POSSUMweb, Victorian Clinical Genetics Service and Murdoch Childrens Research Institute, The Royal Children's Hospital, Parkville, VIC, Australia
| | | | | | - Ramzi Temanni
- Bioinformatics Division, Sidra Medical & Research Center, Doha, Qatar
| | - Puthen V Jithesh
- Bioinformatics Division, Sidra Medical & Research Center, Doha, Qatar
| | - Aouatef Chouchane
- Dermatology Research Group, Translational Medicine Division, Sidra Medical & Research Center, Doha, Qatar
| | - Konduru S Sastry
- Dermatology Research Group, Translational Medicine Division, Sidra Medical & Research Center, Doha, Qatar
| | - Remy Thomas
- Laboratory of Genetic Medicine and Immunology, Weill Cornell Medicine-Qatar, Education City, Qatar Foundation, Doha, Qatar
| | - Sara Tomei
- Genomics Core Laboratory, Translational Medicine Division, Sidra Medical & Research Center, Doha, Qatar
| | - Wei Liu
- Genomics Core Laboratory, Translational Medicine Division, Sidra Medical & Research Center, Doha, Qatar
| | | | - Daniel MacArthur
- Medical and Population Genetics, Broad Institute of Harvard Medical School, Boston, USA
| | - Lotfi Chouchane
- Laboratory of Genetic Medicine and Immunology, Weill Cornell Medicine-Qatar, Education City, Qatar Foundation, Doha, Qatar.
| |
Collapse
|
6
|
'Splitting versus lumping': Temple-Baraitser and Zimmermann-Laband Syndromes. Hum Genet 2015; 134:1089-97. [PMID: 26264464 DOI: 10.1007/s00439-015-1590-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 08/03/2015] [Indexed: 10/23/2022]
Abstract
KCNH1 mutations have recently been described in six individuals with Temple-Baraitser syndrome (TMBTS) and six individuals with Zimmermann-Laband syndrome (ZLS). TMBTS is characterized by intellectual disability (ID), epilepsy, dysmorphic facial features, broad thumbs and great toes with absent/hypoplastic nails. ZLS is characterized by facial dysmorphism including coarsening of the face and a large nose, gingival enlargement, ID, hypoplasia of terminal phalanges and nails and hypertrichosis. In this study, we present four additional unrelated individuals with de novo KCNH1 mutations from ID cohorts. We report on a novel recurrent pathogenic KCNH1 variant in three individuals and add a fourth individual with a previously TMBTS-associated KCNH1 variant. Neither TMBTS nor ZLS was suspected clinically. KCNH1 encodes a voltage-gated potassium channel, which is not only highly expressed in the central nervous system, but also seems to play an important role during development. Clinical evaluation of our mutation-positive individuals revealed that one of the main characteristics of TMBTS/ZLS, namely the pronounced nail hypoplasia of the great toes and thumbs, can be mild and develop over time. Clinical comparison of all published KCNH1 mutation-positive individuals revealed a similar facial but variable limb phenotype. KCNH1 mutation-positive individuals present with severe ID, neonatal hypotonia, hypertelorism, broad nasal tip, wide mouth, nail a/hypoplasia, a proximal implanted and long thumb and long great toes. In summary, we show that the phenotypic variability of individuals with KCNH1 mutations is more pronounced than previously expected, and we discuss whether KCNH1 mutations allow for "lumping" or for "splitting" of TMBTS and ZLS.
Collapse
|