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Al-Sarraj Y, Taha RZ, Al-Dous E, Ahram D, Abbasi S, Abuazab E, Shaath H, Habbab W, Errafii K, Bejaoui Y, AlMotawa M, Khattab N, Aqel YA, Shalaby KE, Al-Ansari A, Kambouris M, Abouzohri A, Ghazal I, Tolfat M, Alshaban F, El-Shanti H, Albagha OME. The genetic landscape of autism spectrum disorder in the Middle Eastern population. Front Genet 2024; 15:1363849. [PMID: 38572415 PMCID: PMC10987745 DOI: 10.3389/fgene.2024.1363849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Accepted: 03/04/2024] [Indexed: 04/05/2024] Open
Abstract
Introduction: Autism spectrum disorder (ASD) is characterized by aberrations in social interaction and communication associated with repetitive behaviors and interests, with strong clinical heterogeneity. Genetic factors play an important role in ASD, but about 75% of ASD cases have an undetermined genetic risk. Methods: We extensively investigated an ASD cohort made of 102 families from the Middle Eastern population of Qatar. First, we investigated the copy number variations (CNV) contribution using genome-wide SNP arrays. Next, we employed Next Generation Sequencing (NGS) to identify de novo or inherited variants contributing to the ASD etiology and its associated comorbid conditions in families with complete trios (affected child and the parents). Results: Our analysis revealed 16 CNV regions located in genomic regions implicated in ASD. The analysis of the 88 ASD cases identified 41 genes in 39 ASD subjects with de novo (n = 24) or inherited variants (n = 22). We identified three novel de novo variants in new candidate genes for ASD (DTX4, ARMC6, and B3GNT3). Also, we have identified 15 de novo variants in genes that were previously implicated in ASD or related neurodevelopmental disorders (PHF21A, WASF1, TCF20, DEAF1, MED13, CREBBP, KDM6B, SMURF1, ADNP, CACNA1G, MYT1L, KIF13B, GRIA2, CHM, and KCNK9). Additionally, we defined eight novel recessive variants (RYR2, DNAH3, TSPYL2, UPF3B KDM5C, LYST, and WNK3), four of which were X-linked. Conclusion: Despite the ASD multifactorial etiology that hinders ASD genetic risk discovery, the number of identified novel or known putative ASD genetic variants was appreciable. Nevertheless, this study represents the first comprehensive characterization of ASD genetic risk in Qatar's Middle Eastern population.
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Affiliation(s)
- Yasser Al-Sarraj
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
- Qatar Genome Program, Qatar Foundation Research, Development and Innovation, Qatar Foundation, Doha, Qatar
| | - Rowaida Z. Taha
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
| | - Eman Al-Dous
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
| | - Dina Ahram
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
- Quest Diagnostics Nichols Institute, San Juan Capistrano, CA, United States
| | - Somayyeh Abbasi
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
| | - Eman Abuazab
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
| | - Hibah Shaath
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
| | - Wesal Habbab
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
| | - Khaoula Errafii
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
| | - Yosra Bejaoui
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
| | - Maryam AlMotawa
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
| | - Namat Khattab
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
| | - Yasmin Abu Aqel
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
| | - Karim E. Shalaby
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
| | - Amina Al-Ansari
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
| | - Marios Kambouris
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
- Pathology & Laboratory Medicine Department, Genetics Division, Sidra Medicine, Doha, Qatar
| | - Adel Abouzohri
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
| | - Iman Ghazal
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
| | - Mohammed Tolfat
- The Shafallah Center for Children with Special Needs, Doha, Qatar
| | - Fouad Alshaban
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
| | - Hatem El-Shanti
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Omar M. E. Albagha
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
- Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University, Doha, Qatar
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Zhang Q, Qin Z, Hu R, Li Y, Yang F, Li J. A rare early-onset neonatal case of Birk-Barel syndrome presenting severe obstructive sleep apnea: a case report. Front Med (Lausanne) 2023; 10:1180337. [PMID: 37358997 PMCID: PMC10285152 DOI: 10.3389/fmed.2023.1180337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 05/15/2023] [Indexed: 06/28/2023] Open
Abstract
Background Birk-Barel syndrome, also known as KCNK9 imprinting syndrome, is a rare fertility disorder. And the main clinical manifestations include congenital hypotonic, craniofacial malformation, developmental delay, and intellectual disability. Generally, such patients could be diagnosed beyond the infant period. Moreover, the delayed diagnosis might lead to a poor prognosis of rehabilitation therapy. However, neonatal obstructive sleep apnea (OSA) was seldom reported in Birk-Barel syndrome. Here, we reported a severe neonatal OSA case induced by Birk-Barel syndrome, resulting in an early diagnosis with improved outcomes by integrative management. Case presentation The proband was a neonate presenting with recurrent severe OSA, with craniofacial deformity and congenital muscle hypotonia. Bronchoscopy examinations indicated a negative finding of pharyngeal and bronchus stenosis, while laryngomalacia had been observed. Whole exon sequencing demonstrated a c. 710C>A heterozygous variant resulting in a change of amino acid (p.A237D). This variant resulted in a change of amino acid sequence, affected protein features and changed splice site leading to a structural deformation in KCNK9 protein. This p.A237D variant also affected the crystal structure on the p.G129 site. Additionally, we used the mSCM tool to measure the free energy changes between wild-type and mutant protein, which indicated highly destabilizing (-2.622 kcal/mol). Conclusion This case report expands the understanding of Birk-Barel syndrome and indicates that OSA could serve as the on-set manifestation of Birk-Barel syndrome. This case emphasized genetic variants which were associated with severe neonatal OSA. Adequate WES assessment promotes early intervention and improves the prognosis of neurological disorders in young children.
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Affiliation(s)
- Qian Zhang
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Zhen Qin
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
| | - Ruolan Hu
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yifei Li
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Fan Yang
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Jinrong Li
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
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3
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Birk-Barel Intellectual Disability Dimorphism and KCNK9 Imprinting Syndrome: Craniofacial Surgery Considerations for an Exceedingly Rare Syndrome. J Craniofac Surg 2023; 34:e25-e28. [PMID: 35949010 DOI: 10.1097/scs.0000000000008890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Accepted: 06/06/2022] [Indexed: 01/11/2023] Open
Abstract
Birk-Barel intellectual disability dimorphism syndrome, also referred to as KCNK9 imprinting syndrome, is an exceedingly rare condition described in under 20 cases that presents with intellectual disability, hypotonia, scoliosis, dysphonia, dysphagia, and craniofacial dysmorphic features. The condition follows an autosomal dominant pattern of inheritance in the maternally expressed KCNK9 gene on chromosome 8. Due to the complexity of presentation, patients with Birk-Barel syndrome are optimally managed by a multidisciplinary team including a craniofacial surgeon. Previously described craniofacial dysmorphic features include micrognathia, cleft palate, dolichocephaly, broad nasal tip, and broad philtrum, among others. Here the authors describe a genetically confirmed case that has been managed in our institution's multidisciplinary cleft and craniofacial clinic. The authors aim to discuss Birk-Barel syndrome for a surgical and craniofacial audience with considerations for operative management in the context of a multidisciplinary team.
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Fan X, Lu Y, Du G, Liu J. Advances in the Understanding of Two-Pore Domain TASK Potassium Channels and Their Potential as Therapeutic Targets. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238296. [PMID: 36500386 PMCID: PMC9736439 DOI: 10.3390/molecules27238296] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/09/2022] [Accepted: 11/15/2022] [Indexed: 11/29/2022]
Abstract
TWIK-related acid-sensitive K+ (TASK) channels, including TASK-1, TASK-3, and TASK-5, are important members of the two-pore domain potassium (K2P) channel family. TASK-5 is not functionally expressed in the recombinant system. TASK channels are very sensitive to changes in extracellular pH and are active during all membrane potential periods. They are similar to other K2P channels in that they can create and use background-leaked potassium currents to stabilize resting membrane conductance and repolarize the action potential of excitable cells. TASK channels are expressed in both the nervous system and peripheral tissues, including excitable and non-excitable cells, and are widely engaged in pathophysiological phenomena, such as respiratory stimulation, pulmonary hypertension, arrhythmia, aldosterone secretion, cancers, anesthesia, neurological disorders, glucose homeostasis, and visual sensitivity. Therefore, they are important targets for innovative drug development. In this review, we emphasized the recent advances in our understanding of the biophysical properties, gating profiles, and biological roles of TASK channels. Given the different localization ranges and biologically relevant functions of TASK-1 and TASK-3 channels, the development of compounds that selectively target TASK-1 and TASK-3 channels is also summarized based on data reported in the literature.
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Affiliation(s)
- Xueming Fan
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu 610041, China
- Department of Anesthesiology, Guizhou Provincial People’s Hospital, Guiyang 550002, China
| | - Yongzhi Lu
- Guangdong Provincial Key Laboratory of Biocomputing, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510700, China
| | - Guizhi Du
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu 610041, China
- Correspondence: (G.D.); (J.L.)
| | - Jin Liu
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu 610041, China
- Correspondence: (G.D.); (J.L.)
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DeLorenzo L, DeBrock V, Carmona Baez A, Ciccotto PJ, Peterson EN, Stull C, Roberts NB, Roberts RB, Powder KE. Morphometric and Genetic Description of Trophic Adaptations in Cichlid Fishes. BIOLOGY 2022; 11:biology11081165. [PMID: 36009792 PMCID: PMC9405370 DOI: 10.3390/biology11081165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/28/2022] [Accepted: 07/30/2022] [Indexed: 11/16/2022]
Abstract
Since Darwin, biologists have sought to understand the evolution and origins of phenotypic adaptations. The skull is particularly diverse due to intense natural selection on feeding biomechanics. We investigated the genetic and molecular origins of trophic adaptation using Lake Malawi cichlids, which have undergone an exemplary evolutionary radiation. We analyzed morphological differences in the lateral and ventral head shape among an insectivore that eats by suction feeding, an obligate biting herbivore, and their F2 hybrids. We identified variation in a series of morphological traits—including mandible width, mandible length, and buccal length—that directly affect feeding kinematics and function. Using quantitative trait loci (QTL) mapping, we found that many genes of small effects influence these craniofacial adaptations. Intervals for some traits were enriched in genes related to potassium transport and sensory systems, the latter suggesting co-evolution of feeding structures and sensory adaptations for foraging. Despite these indications of co-evolution of structures, morphological traits did not show covariation. Furthermore, phenotypes largely mapped to distinct genetic intervals, suggesting that a common genetic basis does not generate coordinated changes in shape. Together, these suggest that craniofacial traits are mostly inherited as separate modules, which confers a high potential for the evolution of morphological diversity. Though these traits are not restricted by genetic pleiotropy, functional demands of feeding and sensory structures likely introduce constraints on variation. In all, we provide insights into the quantitative genetic basis of trophic adaptation, identify mechanisms that influence the direction of morphological evolution, and provide molecular inroads to craniofacial variation.
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Affiliation(s)
- Leah DeLorenzo
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - Victoria DeBrock
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - Aldo Carmona Baez
- Department of Biological Sciences and Genetics and Genomics Academy, North Carolina State University, Raleigh, NC 27695, USA
| | - Patrick J Ciccotto
- Department of Biological Sciences and Genetics and Genomics Academy, North Carolina State University, Raleigh, NC 27695, USA
- Department of Biology, Warren Wilson College, Swannanoa, NC 28778, USA
| | - Erin N Peterson
- Department of Biological Sciences and Genetics and Genomics Academy, North Carolina State University, Raleigh, NC 27695, USA
| | - Clare Stull
- Department of Biological Sciences and Genetics and Genomics Academy, North Carolina State University, Raleigh, NC 27695, USA
| | - Natalie B Roberts
- Department of Biological Sciences and Genetics and Genomics Academy, North Carolina State University, Raleigh, NC 27695, USA
| | - Reade B Roberts
- Department of Biological Sciences and Genetics and Genomics Academy, North Carolina State University, Raleigh, NC 27695, USA
| | - Kara E Powder
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
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6
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Krgovic D, Gorenjak M, Rihar N, Opalic I, Stangler Herodez S, Gregoric Kumperscak H, Dovc P, Kokalj Vokac N. Impaired Neurodevelopmental Genes in Slovenian Autistic Children Elucidate the Comorbidity of Autism With Other Developmental Disorders. Front Mol Neurosci 2022; 15:912671. [PMID: 35813072 PMCID: PMC9259896 DOI: 10.3389/fnmol.2022.912671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 05/11/2022] [Indexed: 11/13/2022] Open
Abstract
Autism spectrum disorders (ASD) represent a phenotypically heterogeneous group of patients that strongly intertwine with other neurodevelopmental disorders (NDDs), with genetics playing a significant role in their etiology. Whole exome sequencing (WES) has become predominant in molecular diagnostics for ASD by considerably increasing the diagnostic yield. However, the proportion of undiagnosed patients still remains high due to complex clinical presentation, reduced penetrance, and lack of segregation analysis or clinical information. Thus, reverse phenotyping, where we first identified a possible genetic cause and then determine its clinical relevance, has been shown to be a more efficient approach. WES was performed on 147 Slovenian pediatric patients with suspected ASD. Data analysis was focused on identifying ultrarare or “single event” variants in ASD-associated genes and further expanded to NDD-associated genes. Protein function and gene prioritization were performed on detected clinically relevant variants to determine their role in ASD etiology and phenotype. Reverse phenotyping revealed a pathogenic or likely pathogenic variant in ASD-associated genes in 20.4% of patients, with subsequent segregation analysis indicating that 14 were de novo variants and 1 was presumed compound heterozygous. The diagnostic yield was further increased by 2.7% by the analysis of ultrarare or “single event” variants in all NDD-associated genes. Protein function analysis established that genes in which variants of unknown significance (VUS) were detected were predominantly the cause of intellectual disability (ID), and in most cases, features of ASD as well. Using such an approach, variants in rarely described ASD-associated genes, such as SIN3B, NR4A2, and GRIA1, were detected. By expanding the analysis to include functionally similar NDD genes, variants in KCNK9, GNE, and other genes were identified. These would probably have been missed by classic genotype–phenotype analysis. Our study thus demonstrates that in patients with ASD, analysis of ultrarare or “single event” variants obtained using WES with the inclusion of functionally similar genes and reverse phenotyping obtained a higher diagnostic yield despite limited clinical data. The present study also demonstrates that most of the causative genes in our cohort were involved in the syndromic form of ASD and confirms their comorbidity with other developmental disorders.
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Affiliation(s)
- Danijela Krgovic
- Laboratory of Medical Genetics, University Medical Centre Maribor, Maribor, Slovenia
- Department of Molecular Biology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
- *Correspondence: Danijela Krgovic,
| | - Mario Gorenjak
- Centre for Human Molecular Genetics, and Pharmacogenomics, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Nika Rihar
- Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Iva Opalic
- Laboratory of Medical Genetics, University Medical Centre Maribor, Maribor, Slovenia
| | - Spela Stangler Herodez
- Laboratory of Medical Genetics, University Medical Centre Maribor, Maribor, Slovenia
- Department of Molecular Biology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | | | - Peter Dovc
- Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Nadja Kokalj Vokac
- Laboratory of Medical Genetics, University Medical Centre Maribor, Maribor, Slovenia
- Department of Molecular Biology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
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7
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Gain and loss of TASK3 channel function and its regulation by novel variation cause KCNK9 imprinting syndrome. Genome Med 2022; 14:62. [PMID: 35698242 PMCID: PMC9195326 DOI: 10.1186/s13073-022-01064-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 05/19/2022] [Indexed: 11/10/2022] Open
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.
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8
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Zhou C, Zhou Q, He X, He Y, Wang X, Zhu X, Zhang Y, Ma L. Differential modulation of C. elegans motor behavior by NALCN and two-pore domain potassium channels. PLoS Genet 2022; 18:e1010126. [PMID: 35482723 PMCID: PMC9049526 DOI: 10.1371/journal.pgen.1010126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 02/28/2022] [Indexed: 11/18/2022] Open
Abstract
Two-pore domain potassium channels (K2P) are a large family of “background” channels that allow outward “leak” of potassium ions. The NALCN/UNC80/UNC79 complex is a non-selective channel that allows inward flow of sodium and other cations. It is unclear how K2Ps and NALCN differentially modulate animal behavior. Here, we found that loss of function (lf) in the K2P gene twk-40 suppressed the reduced body curvatures of C. elegans NALCN(lf) mutants. twk-40(lf) caused a deep body curvature and extended backward locomotion, and these phenotypes appeared to be associated with neuron-specific expression of twk-40 and distinct twk-40 transcript isoforms. To survey the functions of other less studied K2P channels, we examined loss-of-function mutants of 13 additional twk genes expressed in the motor circuit and detected defective body curvature and/or locomotion in mutants of twk-2, twk-17, twk-30, twk-48, unc-58, and the previously reported twk-7. We generated presumptive gain-of-function (gf) mutations in twk-40, twk-2, twk-7, and unc-58 and found that they caused paralysis. Further analyses detected variable genetic interactions between twk-40 and other twk genes, an interdependence between twk-40 and twk-2, and opposite behavioral effects between NALCN and twk-2, twk-7, or unc-58. Finally, we found that the hydrophobicity/hydrophilicity property of TWK-40 residue 159 could affect the channel activity. Together, our study identified twk-40 as a novel modulator of the motor behavior, uncovered potential behavioral effects of five other K2P genes and suggests that NALCN and some K2Ps can oppositely affect C. elegans behavior.
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Affiliation(s)
- Chuanman Zhou
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Qian Zhou
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Xiaohui He
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Yunxia He
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Xiaoqin Wang
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Xiaowei Zhu
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Yujia Zhang
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Long Ma
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Animal Models for Human Diseases, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Medical Genetics, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Molecular Precision Medicine, Central South University, Changsha, Hunan, China
- * E-mail:
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Zaletaev DV, Nemtsova MV, Strelnikov VV. Epigenetic Regulation Disturbances on Gene Expression in Imprinting Diseases. Mol Biol 2022. [DOI: 10.1134/s0026893321050149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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Contribution of Neuronal and Glial Two-Pore-Domain Potassium Channels in Health and Neurological Disorders. Neural Plast 2021; 2021:8643129. [PMID: 34434230 PMCID: PMC8380499 DOI: 10.1155/2021/8643129] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 08/03/2021] [Indexed: 02/05/2023] Open
Abstract
Two-pore-domain potassium (K2P) channels are widespread in the nervous system and play a critical role in maintaining membrane potential in neurons and glia. They have been implicated in many stress-relevant neurological disorders, including pain, sleep disorder, epilepsy, ischemia, and depression. K2P channels give rise to leaky K+ currents, which stabilize cellular membrane potential and regulate cellular excitability. A range of natural and chemical effectors, including temperature, pressure, pH, phospholipids, and intracellular signaling molecules, substantially modulate the activity of K2P channels. In this review, we summarize the contribution of K2P channels to neuronal excitability and to potassium homeostasis in glia. We describe recently discovered functions of K2P channels in glia, such as astrocytic passive conductance and glutamate release, microglial surveillance, and myelin generation by oligodendrocytes. We also discuss the potential role of glial K2P channels in neurological disorders. In the end, we discuss current limitations in K2P channel researches and suggest directions for future studies.
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Ramirez-Arenalde MA, Bruckman-Blanco WJ, Frontanes-Heredia A, Santiago-Castro SL, De Jesús-Rojas W. An Extremely Rare Case of Birk-Barel Syndrome With Severe Central Apneas. Cureus 2021; 13:e15862. [PMID: 34327088 PMCID: PMC8301725 DOI: 10.7759/cureus.15862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/23/2021] [Indexed: 11/12/2022] Open
Abstract
Birk-Barel syndrome, alternatively known as KCNK9 imprinting syndrome, is caused by a missense mutation in the potassium two pore domain channel subfamily K member 9 (KCNK9) gene on chromosome 8q24.3. This syndrome demonstrates dominant inheritance and is imprinted with paternal silencing, where the paternally inherited allele is silenced, and the maternally inherited allele is active. Congenital hypotonia, palatal abnormalities, intellectual disability, severe feeding difficulties, and dysmorphic facial features characterize this sporadic genetic syndrome. To date, there are approximately 21 molecularly diagnosed individuals worldwide described in the literature. We describe the first known case of Puerto Rican ethnicity, a 16-month-old female born prematurely at 36-weeks with Birk-Barel syndrome, confirmed with whole-exome sequencing, and her response to non-invasive ventilation as a treatment for her sleep breathing disorder.
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Affiliation(s)
| | | | - Abymael Frontanes-Heredia
- Pediatrics, Centro Médico Menonita de Cayey, Cayey, PRI.,Pediatrics, Universidad Central del Caribe School of Medicine, Bayamón, PRI
| | | | - Wilfredo De Jesús-Rojas
- Pediatrics, Ponce Health Sciences University, Ponce, PRI.,Pediatrics, Centro Médico Menonita de Cayey, Cayey, PRI.,Pediatrics, University of Puerto Rico, Medical Sciences Campus, San Juan, PRI.,Pediatrics, San Juan Bautista School of Medicine, Caguas, PRI
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12
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Bhatia NS, Lim JY, Bonnard C, Kuan JL, Brett M, Wei H, Cham B, Chin H, Bosso-Lefevre C, Dharuman P, Escande-Beillard N, Devasia AG, Goh CYJ, Kam S, Liew WKM, Liew WK, Lin G, Jain K, Ng AYJ, Subramanian D, Xie M, Tan YM, Tawari NR, Tiang Z, Ting TW, Tohari S, Tong CK, Lezhava A, Ng SB, Law HY, Venkatesh B, Tomar S, Sethi R, Tan G, Shanmugasundaram A, Goh DLM, Lai PS, Lai A, Tan ES, Ng I, Reversades B, Tan EC, Foo R, Jamuar SS. Singapore Undiagnosed Disease Program: Genomic Analysis aids Diagnosis and Clinical Management. Arch Dis Child 2021; 106:31-37. [PMID: 32819910 DOI: 10.1136/archdischild-2020-319180] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 06/30/2020] [Accepted: 07/02/2020] [Indexed: 12/27/2022]
Abstract
OBJECTIVE Use next-generation sequencing (NGS) technology to improve our diagnostic yield in patients with suspected genetic disorders in the Asian setting. DESIGN A diagnostic study conducted between 2014 and 2019 (and ongoing) under the Singapore Undiagnosed Disease Program. Date of last analysis was 1 July 2019. SETTING Inpatient and outpatient genetics service at two large academic centres in Singapore. PATIENTS Inclusion criteria: patients suspected of genetic disorders, based on abnormal antenatal ultrasound, multiple congenital anomalies and developmental delay. EXCLUSION CRITERIA patients with known genetic disorders, either after clinical assessment or investigations (such as karyotype or chromosomal microarray). INTERVENTIONS Use of NGS technology-whole exome sequencing (WES) or whole genome sequencing (WGS). MAIN OUTCOME MEASURES (1) Diagnostic yield by sequencing type, (2) diagnostic yield by phenotypical categories, (3) reduction in time to diagnosis and (4) change in clinical outcomes and management. RESULTS We demonstrate a 37.8% diagnostic yield for WES (n=172) and a 33.3% yield for WGS (n=24). The yield was higher when sequencing was conducted on trios (40.2%), as well as for certain phenotypes (neuromuscular, 54%, and skeletal dysplasia, 50%). In addition to aiding genetic counselling in 100% of the families, a positive result led to a change in treatment in 27% of patients. CONCLUSION Genomic sequencing is an effective method for diagnosing rare disease or previous 'undiagnosed' disease. The clinical utility of WES/WGS is seen in the shortened time to diagnosis and the discovery of novel variants. Additionally, reaching a diagnosis significantly impacts families and leads to alteration in management of these patients.
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Affiliation(s)
- Neha S Bhatia
- Department of Paediatrics, KK Women's and Children's Hospital, Singapore.,Division of Genetics and Metabolism, Tufts Medical Center and the Floating Hospital for Children, Boston, Massachusetts, USA
| | - Jiin Ying Lim
- Department of Paediatrics, KK Women's and Children's Hospital, Singapore
| | | | - Jyn-Ling Kuan
- Department of Paediatrics, KK Women's and Children's Hospital, Singapore.,SingHealth Duke-NUS Institute of Precision Medicine, Singapore
| | - Maggie Brett
- KK Research Centre, KK Women's and Children's Hospital, Singapore
| | - Heming Wei
- KK Research Centre, KK Women's and Children's Hospital, Singapore
| | - Breana Cham
- Department of Paediatrics, KK Women's and Children's Hospital, Singapore
| | - Huilin Chin
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Khoo Teck Puat-National University Children's Medical Institute, National University Health System, Singapore
| | - Celia Bosso-Lefevre
- Institute of Medical Biology, A*STAR, Singapore.,Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | | | | | | | | | - Sylvia Kam
- Department of Paediatrics, KK Women's and Children's Hospital, Singapore.,SingHealth Duke-NUS Institute of Precision Medicine, Singapore
| | - Wendy Kein-Meng Liew
- Department of Paediatrics, KK Women's and Children's Hospital, Singapore.,SBCC Baby and Child Clinic, Singapore
| | - Woei Kang Liew
- Department of Paediatrics, KK Women's and Children's Hospital, Singapore.,SBCC Baby and Child Clinic, Singapore
| | - Grace Lin
- KK Research Centre, KK Women's and Children's Hospital, Singapore
| | - Kanika Jain
- Department of Paediatrics, KK Women's and Children's Hospital, Singapore.,POLARIS, Genome Institute of Singapore, Singapore
| | | | | | - Min Xie
- POLARIS, Genome Institute of Singapore, Singapore
| | - Yuen-Ming Tan
- Department of Paediatrics, KK Women's and Children's Hospital, Singapore.,DNA Diagnostic and Research Laboratory, KK Women's and Children's Hospital, Singapore
| | | | - Zenia Tiang
- Cardiovascular Research Institute, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Genome Institute of Singapore, A*STAR, Singapore
| | - Teck Wah Ting
- Department of Paediatrics, KK Women's and Children's Hospital, Singapore.,Paediatrics Academic Clinical Programme, Duke-NUS Medical School, Singapore.,SingHealth Duke-NUS Genomic Medicine Centre, Singapore
| | - Sumanty Tohari
- Institute of Molecular and Cell Biology, A*STAR, Singapore
| | | | | | - Sarah B Ng
- POLARIS, Genome Institute of Singapore, Singapore
| | - Hai Yang Law
- Department of Paediatrics, KK Women's and Children's Hospital, Singapore.,DNA Diagnostic and Research Laboratory, KK Women's and Children's Hospital, Singapore.,Paediatrics Academic Clinical Programme, Duke-NUS Medical School, Singapore
| | - Byrappa Venkatesh
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Institute of Molecular and Cell Biology, A*STAR, Singapore
| | - Swati Tomar
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Khoo Teck Puat-National University Children's Medical Institute, National University Health System, Singapore
| | - Raman Sethi
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Khoo Teck Puat-National University Children's Medical Institute, National University Health System, Singapore
| | - Grace Tan
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Khoo Teck Puat-National University Children's Medical Institute, National University Health System, Singapore
| | - Arthi Shanmugasundaram
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Khoo Teck Puat-National University Children's Medical Institute, National University Health System, Singapore
| | - Denise Li-Meng Goh
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Khoo Teck Puat-National University Children's Medical Institute, National University Health System, Singapore
| | - Poh San Lai
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Khoo Teck Puat-National University Children's Medical Institute, National University Health System, Singapore.,Genome Institute of Singapore, A*STAR, Singapore
| | - Angeline Lai
- Department of Paediatrics, KK Women's and Children's Hospital, Singapore.,Paediatrics Academic Clinical Programme, Duke-NUS Medical School, Singapore.,SingHealth Duke-NUS Genomic Medicine Centre, Singapore
| | - Ee Shien Tan
- Department of Paediatrics, KK Women's and Children's Hospital, Singapore.,Paediatrics Academic Clinical Programme, Duke-NUS Medical School, Singapore.,SingHealth Duke-NUS Genomic Medicine Centre, Singapore
| | - Ivy Ng
- Department of Paediatrics, KK Women's and Children's Hospital, Singapore.,Paediatrics Academic Clinical Programme, Duke-NUS Medical School, Singapore.,SingHealth Duke-NUS Genomic Medicine Centre, Singapore
| | - Bruno Reversades
- Institute of Medical Biology, A*STAR, Singapore.,Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,POLARIS, Genome Institute of Singapore, Singapore.,Institute of Molecular and Cell Biology, A*STAR, Singapore
| | - Ene Choo Tan
- KK Research Centre, KK Women's and Children's Hospital, Singapore.,Paediatrics Academic Clinical Programme, Duke-NUS Medical School, Singapore
| | - Roger Foo
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,POLARIS, Genome Institute of Singapore, Singapore.,Cardiovascular Research Institute, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Genome Institute of Singapore, A*STAR, Singapore.,National University Heart Centre, National University Health System, Singapore
| | - Saumya Shekhar Jamuar
- Department of Paediatrics, KK Women's and Children's Hospital, Singapore .,SingHealth Duke-NUS Institute of Precision Medicine, Singapore.,Paediatrics Academic Clinical Programme, Duke-NUS Medical School, Singapore.,SingHealth Duke-NUS Genomic Medicine Centre, Singapore
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13
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46,XY,r(8)/45,XY,-8 Mosaicism as a Possible Mechanism of the Imprinted Birk-Barel Syndrome: A Case Study. Genes (Basel) 2020; 11:genes11121473. [PMID: 33316910 PMCID: PMC7763634 DOI: 10.3390/genes11121473] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 11/25/2020] [Accepted: 12/07/2020] [Indexed: 12/27/2022] Open
Abstract
Ring chromosome 8 (r(8)) is one of the least frequent ring chromosomes. Usually, maternal chromosome 8 forms a ring, which can be lost from cells due to mitotic instability. The 8q24 region contains the imprinted KCNK9 gene, which is expressed from the maternal allele. Heterozygous KCNK9 mutations are associated with the imprinting disorder Birk-Barel syndrome. Here, we report a 2.5-year-old boy with developmental delay, microcephaly, dysmorphic features, diffuse muscle hypotonia, feeding problems, motor alalia and noncoarse neurogenic type of disturbance of muscle electrogenesis, partially overlapping with Birk-Barel syndrome phenotype. Cytogenetic analysis of lymphocytes revealed his karyotype to be 46,XY,r(8)(p23q24.3)[27]/45,XY,−8[3]. A de novo 7.9 Mb terminal 8p23.3p23.1 deletion, a 27.1 Mb 8p23.1p11.22 duplication, and a 4.4 Mb intact segment with a normal copy number located between them, as well as a 154-kb maternal LINGO2 gene deletion (9p21.2) with unknown clinical significance were identified by aCGH + SNP array. These aberrations were confirmed by real-time PCR. According to FISH analysis, the 8p23.1-p11.22 duplication was inverted. The ring chromosome originated from maternal chromosome 8. Targeted massive parallel sequencing did not reveal the KCNK9 mutations associated with Birk-Barel syndrome. Our data allow to assume that autosomal monosomy with inactive allele of imprinted gene arising from the loss of a ring chromosome in some somatic cells may be an etiological mechanism of mosaic imprinting disorders, presumably with less severe phenotype.
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14
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Elbracht M, Binder G, Hiort O, Kiewert C, Kratz C, Eggermann T. Clinical spectrum and management of imprinting disorders. MED GENET-BERLIN 2020. [DOI: 10.1515/medgen-2020-2044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Imprinting disorders are exceptional within the group of monogenic syndromes. They are associated with molecular changes affecting imprinted regions and usually do not follow the rules of Mendelian inheritance. They account for a relevant proportion of congenital disorders, especially within the syndromal growth entities with endocrine, neurological, and skeletal characteristics. In patients with imprinting disorders and accelerated growth, significant tumor risks have to be considered. The number of known imprinting disorders increases with the identification of new regions in which parentally imprinted genes are located. Imprinting disorders are caused by genomic pathogenic variants affecting imprinted genes, as well as by aberrant imprinting marks (epimutations) in the patients themselves. Additionally, maternal effect mutations have recently been identified that trigger secondary epimutations in the offspring. These maternal effect mutations explain not only imprinting disorders in their children, but also recurrent reproductive failure in the families. This review aims to provide an overview of the recent findings in 13 well-known imprinting disorders relating to clinical diagnosis, management and counseling.
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Affiliation(s)
- Miriam Elbracht
- Institute of Human Genetics, Medical Faculty , RWTH Aachen University , Pauwelsstr. 30 , Aachen , Germany
| | - Gerhard Binder
- Pädiatrische Endokrinologie, Universitätsklinik für Kinder- und Jugendmedizin , Universitätsklinikum Tübingen , Tübingen , Germany
| | - Olaf Hiort
- Department of Paediatrics and Adolescent Medicine, Division of Paediatric Endocrinology and Diabetes , University of Lübeck , Lübeck , Germany
| | - Cordula Kiewert
- Pediatric Endocrinology and Diabetology , Children’s University Hospital Essen , Essen , Germany
| | - Christian Kratz
- Department of Pediatric Hematology and Oncology , Hannover Medical School , Hannover , Germany
| | - Thomas Eggermann
- Institute of Human Genetics, Medical Faculty , RWTH Aachen University , Pauwelsstr. 30 , Aachen , Germany
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15
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Mathie A, Veale EL, Cunningham KP, Holden RG, Wright PD. Two-Pore Domain Potassium Channels as Drug Targets: Anesthesia and Beyond. Annu Rev Pharmacol Toxicol 2020; 61:401-420. [PMID: 32679007 DOI: 10.1146/annurev-pharmtox-030920-111536] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Two-pore domain potassium (K2P) channels stabilize the resting membrane potential of both excitable and nonexcitable cells and, as such, are important regulators of cell activity. There are many conditions where pharmacological regulation of K2P channel activity would be of therapeutic benefit, including, but not limited to, atrial fibrillation, respiratory depression, pulmonary hypertension, neuropathic pain, migraine, depression, and some forms of cancer. Up until now, few if any selective pharmacological regulators of K2P channels have been available. However, recent publications of solved structures with small-molecule activators and inhibitors bound to TREK-1, TREK-2, and TASK-1 K2P channels have given insight into the pharmacophore requirements for compound binding to these sites. Together with the increasing availability of a number of novel, active, small-molecule compounds from K2P channel screening programs, these advances have opened up the possibility of rational activator and inhibitor design to selectively target K2P channels.
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Affiliation(s)
- Alistair Mathie
- Medway School of Pharmacy, University of Greenwich and University of Kent, Kent ME4 4TB, United Kingdom;
| | - Emma L Veale
- Medway School of Pharmacy, University of Greenwich and University of Kent, Kent ME4 4TB, United Kingdom;
| | - Kevin P Cunningham
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, United Kingdom
| | - Robyn G Holden
- Medway School of Pharmacy, University of Greenwich and University of Kent, Kent ME4 4TB, United Kingdom;
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16
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TASK channels: channelopathies, trafficking, and receptor-mediated inhibition. Pflugers Arch 2020; 472:911-922. [DOI: 10.1007/s00424-020-02403-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 05/08/2020] [Accepted: 05/18/2020] [Indexed: 01/06/2023]
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17
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"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.
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18
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Abstract
Imprinting disorders are a group of congenital diseases caused by dysregulation of genomic imprinting, affecting prenatal and postnatal growth, neurocognitive development, metabolism and cancer predisposition. Aberrant expression of imprinted genes can be achieved through different mechanisms, classified into epigenetic - if not involving DNA sequence change - or genetic in the case of altered genomic sequence. Despite the underlying mechanism, the phenotype depends on the parental allele affected and opposite phenotypes may result depending on the involvement of the maternal or the paternal chromosome. Imprinting disorders are largely underdiagnosed because of the broad range of clinical signs, the overlap of presentation among different disorders, the presence of mild phenotypes, the mitigation of the phenotype with age and the limited availability of molecular techniques employed for diagnosis. This review briefly illustrates the currently known human imprinting disorders, highlighting endocrinological aspects of pediatric interest.
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Affiliation(s)
- Diana Carli
- University of Torino, Department of Pediatric and Public Health Sciences, Torino, Italy
| | - Evelise Riberi
- University of Torino, Department of Pediatric and Public Health Sciences, Torino, Italy
| | | | - Alessandro Mussa
- University of Torino, Department of Pediatric and Public Health Sciences, Torino, Italy,* Address for Correspondence: University of Torino, Department of Pediatric and Public Health Sciences, Torino, Italy Phone: +39-011-313-1985 E-mail:
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19
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Cunningham KP, MacIntyre DE, Mathie A, Veale EL. Effects of the ventilatory stimulant, doxapram on human TASK-3 (KCNK9, K2P9.1) channels and TASK-1 (KCNK3, K2P3.1) channels. Acta Physiol (Oxf) 2020; 228:e13361. [PMID: 31423744 PMCID: PMC7003846 DOI: 10.1111/apha.13361] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 08/14/2019] [Accepted: 08/15/2019] [Indexed: 01/16/2023]
Abstract
AIMS The mode of action by which doxapram acts as a respiratory stimulant in humans is controversial. Studies in rodent models, have shown that doxapram is a more potent and selective inhibitor of TASK-1 and TASK-1/TASK-3 heterodimer channels, than TASK-3. Here we investigate the direct effect of doxapram and chirally separated, individual positive and negative enantiomers of the compound, on both human and mouse, homodimeric and heterodimeric variants of TASK-1 and TASK-3. METHODS Whole-cell patch clamp electrophysiology on tsA201 cells was used to assess the potency of doxapram on cloned human or mouse TASK-1, TASK-3 and TASK-2 channels. Mutations of amino acids in the pore-lining region of TASK-3 channels were introduced using site-directed mutagenesis. RESULTS Doxapram was an equipotent inhibitor of human TASK-1 and TASK-3 channels, compared with mouse channel variants, where it was more selective for TASK-1 and heterodimers of TASK-1 and TASK-3. The effect of doxapram could be attenuated by either the removal of the C-terminus of human TASK-3 channels or mutations of particular hydrophobic residues in the pore-lining region. These mutations, however, did not alter the effect of a known extracellular inhibitor of TASK-3, zinc. The positive enantiomer of doxapram, GAL-054, was a more potent antagonist of TASK channels, than doxapram, whereas the negative enantiomer, GAL-053, had little inhibitory effect. CONCLUSION These data show that in contrast to rodent channels, doxapram is a potent inhibitor of both TASK-1 and TASK-3 human channels, providing further understanding of the pharmacological profile of doxapram in humans and informing the development of new therapeutic agents.
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Affiliation(s)
- Kevin P. Cunningham
- Medway School of PharmacyUniversity of Greenwich and University of KentChatham MaritimeUK
| | - D. Euan MacIntyre
- Department of Drug DiscoveryGalleon Pharmaceuticals, IncHorshamPennsylvania
| | - Alistair Mathie
- Medway School of PharmacyUniversity of Greenwich and University of KentChatham MaritimeUK
| | - Emma L. Veale
- Medway School of PharmacyUniversity of Greenwich and University of KentChatham MaritimeUK
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20
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Inhibition of histone deacetylation rescues phenotype in a mouse model of Birk-Barel intellectual disability syndrome. Nat Commun 2020; 11:480. [PMID: 31980599 PMCID: PMC6981138 DOI: 10.1038/s41467-019-13918-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 12/05/2019] [Indexed: 01/10/2023] Open
Abstract
Mutations in the actively expressed, maternal allele of the imprinted KCNK9 gene cause Birk-Barel intellectual disability syndrome (BBIDS). Using a BBIDS mouse model, we identify here a partial rescue of the BBIDS-like behavioral and neuronal phenotypes mediated via residual expression from the paternal Kcnk9 (Kcnk9pat) allele. We further demonstrate that the second-generation HDAC inhibitor CI-994 induces enhanced expression from the paternally silenced Kcnk9 allele and leads to a full rescue of the behavioral phenotype suggesting CI-994 as a promising molecule for BBIDS therapy. Thus, these findings suggest a potential approach to improve cognitive dysfunction in a mouse model of an imprinting disorder. Birk-Barel intellectual disability is an imprinting syndrome due to maternally-only transmitted mutations of KCNK9/TASK3. Here authors are using a heterozygous deletion of the active maternal Kcnk9 allele to model the disease and show phenotypic rescue by HDAC inhibition.
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21
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Šedivá M, Laššuthová P, Zámečník J, Sedláčková L, Seeman P, Haberlová J. Novel variant in the KCNK9 gene in a girl with Birk Barel syndrome. Eur J Med Genet 2020; 63:103619. [DOI: 10.1016/j.ejmg.2019.01.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 01/02/2019] [Accepted: 01/19/2019] [Indexed: 11/25/2022]
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22
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Discrimination of DNA Methylation Signal from Background Variation for Clinical Diagnostics. Int J Mol Sci 2019; 20:ijms20215343. [PMID: 31717838 PMCID: PMC6862328 DOI: 10.3390/ijms20215343] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/09/2019] [Accepted: 10/24/2019] [Indexed: 12/29/2022] Open
Abstract
Advances in the study of human DNA methylation variation offer a new avenue for the translation of epigenetic research results to clinical applications. Although current approaches to methylome analysis have been helpful in revealing an epigenetic influence in major human diseases, this type of analysis has proven inadequate for the translation of these advances to clinical diagnostics. As in any clinical test, the use of a methylation signal for diagnostic purposes requires the estimation of an optimal cutoff value for the signal, which is necessary to discriminate a signal induced by a disease state from natural background variation. To address this issue, we propose the application of a fundamental signal detection theory and machine learning approaches. Simulation studies and tests of two available methylome datasets from autism and leukemia patients demonstrate the feasibility of this approach in clinical diagnostics, providing high discriminatory power for the methylation signal induced by disease, as well as high classification performance. Specifically, the analysis of whole biomarker genomic regions could suffice for a diagnostic, markedly decreasing its cost.
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23
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Li WC, Xiong ZY, Huang PZ, Liao YJ, Li QX, Yao ZC, Liao YD, Xu SL, Zhou H, Wang QL, Huang H, Zhang P, Lin JZ, Liu B, Ren J, Hu KP. KCNK levels are prognostic and diagnostic markers for hepatocellular carcinoma. Aging (Albany NY) 2019; 11:8169-8182. [PMID: 31581133 PMCID: PMC6814606 DOI: 10.18632/aging.102311] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 09/21/2019] [Indexed: 12/24/2022]
Abstract
Two-pore-domain (KCNK, K2P) K+ channels are transmembrane protein complexes that control the flow of ions across biofilms, which underlie many essential cellular functions. Because KCNK family members are known to contribute to tumorigenesis in various types of cancer, we hypothesized that they might be differentially expressed in hepatocellular carcinoma (HCC) cells as compared to healthy tissue and serve as diagnostic or prognostic biomarkers. We tested this hypothesis through bioinformatic analyses of publicly available data for the expression of various KCNK subunits in HCC. We observed reduced expression of KCNK2, KCNK15, and KCNK17 in liver cancer, as well as overexpression of KCNK9, all of which correlated with a better prognosis for HCC patients per survival analyses. Moreover, ROC curves indicated that KCNK2, KCNK9, KCNK15, and KCNK17 levels could be used as a diagnostic biomarker for HCC. Finally, our western blot and qRT-PCR results were consistent with those obtained from bioinformatic analyses. Taken together, these results suggest that KCNK2, KCNK9, KCNK15, and KCNK17 could serve as potential diagnostic and prognostic biomarkers of HCC.
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Affiliation(s)
- Wen-Chao Li
- Department of General Surgery, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Zhi-Yong Xiong
- Department of General Surgery, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Pin-Zhu Huang
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yang-Jing Liao
- Department of Traditional Chinese Medicine, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Quan-Xi Li
- Department of Radiology, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Zhi-Cheng Yao
- Department of General Surgery, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Ya-Di Liao
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Shi-Lei Xu
- Department of General Surgery, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Hui Zhou
- Department of General Surgery, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Qing-Liang Wang
- Department of General Surgery, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - He Huang
- Department of General Surgery, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Peng Zhang
- Department of General Surgery, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Ji-Zong Lin
- Department of General Surgery, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Bo Liu
- Department of General Surgery, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Jie Ren
- Department of Ultrasound, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Kun-Peng Hu
- Department of General Surgery, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
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24
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Al-Moubarak E, Veale EL, Mathie A. Pharmacologically reversible, loss of function mutations in the TM2 and TM4 inner pore helices of TREK-1 K2P channels. Sci Rep 2019; 9:12394. [PMID: 31455781 PMCID: PMC6712037 DOI: 10.1038/s41598-019-48855-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 08/09/2019] [Indexed: 01/21/2023] Open
Abstract
A better understanding of the gating of TREK two pore domain potassium (K2P) channels and their activation by compounds such as the negatively charged activator, flufenamic acid (FFA) is critical in the search for more potent and selective activators of these channels. Currents through wild-type and mutated human K2P channels expressed in tsA201 cells were measured using whole-cell patch-clamp recordings in the presence and absence of FFA. Mutation of the TM2.6 residue of TREK-1 to a phenylalanine (G171F) and a similar mutation of TM4.6 (A286F) substantially reduced current through TREK-1 channels. In complementary experiments, replacing the natural F residues at the equivalent position in TRESK channels, significantly enhanced current. Known, gain of function mutations of TREK-1 (G137I, Y284A) recovered current through these mutated channels. This reduction in current could be also be reversed pharmacologically, by FFA. However, an appropriate length MTS (MethaneThioSulfonate) cross-linking reagent (MTS14) restricted the activation of TREK-1_A286C channels by repeated application of FFA. This suggests that the cross-linker stabilises the channel in a conformation which blunts FFA activation. Pharmacologically reversible mutations of TREK channels will help to clarify the importance of these channels in pathophysiological conditions such as pain and depression.
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Affiliation(s)
- Ehab Al-Moubarak
- Medway School of Pharmacy, University of Kent, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK
| | - Emma L Veale
- Medway School of Pharmacy, University of Kent, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK
| | - Alistair Mathie
- Medway School of Pharmacy, University of Kent, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK.
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Abstract
How a single fertilized egg develops into a complex multicellular organism is one of the great mysteries of life. Developmental biology textbooks describe cascades of ligands, receptors, kinases, and transcription factors that designate proliferation, migration, and ultimately fate of cells organized into a multicellular organism. Recently, it has become apparent that ion channels are integral to the process of developmental signaling. Ion channels provide bioelectric signals that must intersect with the known developmental signaling pathways. We review some evidence that bioelectric signaling contributes to bone morphogenetic protein signaling.
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Affiliation(s)
- Laura Faith George
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Trevor Isner
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Emily Anne Bates
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
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Cunningham KP, Holden RG, Escribano-Subias PM, Cogolludo A, Veale EL, Mathie A. Characterization and regulation of wild-type and mutant TASK-1 two pore domain potassium channels indicated in pulmonary arterial hypertension. J Physiol 2018; 597:1087-1101. [PMID: 30365877 PMCID: PMC6376074 DOI: 10.1113/jp277275] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Accepted: 10/24/2018] [Indexed: 12/22/2022] Open
Abstract
Key points The TASK‐1 channel gene (KCNK3) has been identified as a possible disease‐causing gene in heritable pulmonary arterial hypertension (PAH). In the present study, we show that novel mutated TASK‐1 channels, seen in PAH patients, have a substantially reduced current compared to wild‐type TASK‐1 channels. These mutated TASK‐1 channels are located at the plasma membrane to the same degree as wild‐type TASK‐1 channels. ONO‐RS‐082 and alkaline pH 8.4 both activate TASK‐1 channels but do not recover current through mutant TASK‐1 channels. We show that the guanylate cyclase activator, riociguat, a novel treatment for PAH, enhances current through TASK‐1 channels but does not recover current through mutant TASK‐1 channels.
Abstract Pulmonary arterial hypertension (PAH) affects ∼15–50 people per million. KCNK3, the gene that encodes the two pore domain potassium channel TASK‐1 (K2P3.1), has been identified as a possible disease‐causing gene in heritable PAH. Recently, two new mutations have been identified in KCNK3 in PAH patients: G106R and L214R. The present study aimed to characterize the functional properties and regulation of wild‐type (WT) and mutated TASK‐1 channels and determine how these might contribute to PAH and its treatment. Currents through WT and mutated human TASK‐1 channels transiently expressed in tsA201 cells were measured using whole‐cell patch clamp electrophysiology. Localization of fluorescence‐tagged channels was visualized using confocal microscopy and quantified with in‐cell and on‐cell westerns. G106R or L214R mutated channels were located at the plasma membrane to the same degree as WT channels; however, their current was markedly reduced compared to WT TASK‐1 channels. Functional current through these mutated channels could not be restored using activators of WT TASK‐1 channels (pH 8.4, ONO‐RS‐082). The guanylate cyclase activator, riociguat, enhanced current through WT TASK‐1 channels; however, similar to the other activators investigated, riociguat did not have any effect on current through mutated TASK‐1 channels. Thus, novel mutations in TASK‐1 seen in PAH substantially alter the functional properties of these channels. Current through these channels could not be restored by activators of TASK‐1 channels. Riociguat enhancement of current through TASK‐1 channels could contribute to its therapeutic benefit in the treatment of PAH. The TASK‐1 channel gene (KCNK3) has been identified as a possible disease‐causing gene in heritable pulmonary arterial hypertension (PAH). In the present study, we show that novel mutated TASK‐1 channels, seen in PAH patients, have a substantially reduced current compared to wild‐type TASK‐1 channels. These mutated TASK‐1 channels are located at the plasma membrane to the same degree as wild‐type TASK‐1 channels. ONO‐RS‐082 and alkaline pH 8.4 both activate TASK‐1 channels but do not recover current through mutant TASK‐1 channels. We show that the guanylate cyclase activator, riociguat, a novel treatment for PAH, enhances current through TASK‐1 channels but does not recover current through mutant TASK‐1 channels.
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Affiliation(s)
- Kevin P Cunningham
- Medway School of Pharmacy, University of Kent and University of Greenwich, Chatham Maritime, Kent, UK
| | - Robyn G Holden
- Medway School of Pharmacy, University of Kent and University of Greenwich, Chatham Maritime, Kent, UK
| | | | - Angel Cogolludo
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.,Ciber Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Emma L Veale
- Medway School of Pharmacy, University of Kent and University of Greenwich, Chatham Maritime, Kent, UK
| | - Alistair Mathie
- Medway School of Pharmacy, University of Kent and University of Greenwich, Chatham Maritime, Kent, UK
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Wright PD, Veale EL, McCoull D, Tickle DC, Large JM, Ococks E, Gothard G, Kettleborough C, Mathie A, Jerman J. Terbinafine is a novel and selective activator of the two-pore domain potassium channel TASK3. Biochem Biophys Res Commun 2017; 493:444-450. [DOI: 10.1016/j.bbrc.2017.09.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 09/01/2017] [Indexed: 12/12/2022]
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