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Dolu MH, Öz Tunçer G, Akça Ü, Aydın S, Bahadir O, Sezer Ö, Aksoy A, Taşdemir HA. Hyperekplexia: A Single-Center Experience. J Child Neurol 2024:8830738241263243. [PMID: 39051604 DOI: 10.1177/08830738241263243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
BACKGROUND Hyperekplexia is a rare neurogenetic disorder that is classically characterized by an exaggerated startle response to sudden unexpected stimuli. This study aimed to determine clinical and genetic characteristics of our patients with hyperekplexia. METHODS The age of onset and diagnosis, familial and perinatal history, clinical course, complications, metabolic screening tests, magnetic resonance imaging (MRI), medications, neuropsychometric evaluations, and gene mutations of patients diagnosed with hyperekplexia were reviewed retrospectively. RESULTS All hyperekplexia patients had displayed neonatal excessive startle response and muscle stiffness, which we accepted as the major form of the disorder. Sixteen patients had mutations in genes associated with hyperekplexia. The ages at clinical diagnosis and genetic confirmation ranged from newborn to 16 years old and from 2.5 to 19 years, respectively. Nine patients (56.25%) were initially misdiagnosed with epilepsy. Seven patients (43.75%) carried a diagnosis of intellectual disability, defined here as a total IQ <80. Delayed gross motor development was detected in 4 patients (25%), and speech delay was reported in 3 (18.75%). Mutations in GLRA1 (NM_000171.4) and SLC6A5 (NM_004211.5) were identified in 13 (81.25%) and 3 patients (18.75%), respectively. Fifteen of the 16 patients (93.75%) showed autosomal recessive inheritance. Only 1 patient (6.25%) showed autosomal dominant inheritance. CONCLUSION Although hyperekplexia is a potentially treatable disease, it can be complicated by delayed speech and/or motor acquisition and also by intellectual disability. This study shows that hyperekplexia is not always a benign condition and that all patients diagnosed with hyperekplexia should be evaluated for neuropsychiatric status and provided with genetic testing.
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Affiliation(s)
- Merve Hilal Dolu
- Department of Pediatric Neurology, Faculty of Medicine, Ondokuz Mayis University, Samsun, Turkey
| | - Gökçen Öz Tunçer
- Department of Pediatric Neurology, Faculty of Medicine, Ondokuz Mayis University, Samsun, Turkey
| | - Ünal Akça
- Department of Pediatric Neurology, Faculty of Medicine, Ondokuz Mayis University, Samsun, Turkey
| | - Seren Aydın
- Department of Pediatric Neurology, Faculty of Medicine, Ondokuz Mayis University, Samsun, Turkey
| | - Oğuzhan Bahadir
- Department of Medical Genetics, Samsun Education and Research Hospital, Samsun, Turkey
| | - Özlem Sezer
- Department of Medical Genetics, Samsun Education and Research Hospital, Samsun, Turkey
| | - Ayşe Aksoy
- Department of Pediatric Neurology, Faculty of Medicine, Ondokuz Mayis University, Samsun, Turkey
| | - Haydar Ali Taşdemir
- Department of Pediatric Neurology, Faculty of Medicine, Ondokuz Mayis University, Samsun, Turkey
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Tezen D, Şimşir G, Çokar Ö, Demirbilek V, Başak AN, Yapıcı Z. Four Turkish families with hyperekplexia: A missense mutation and the exon 1-7 deletion in the GLRA1 gene. Parkinsonism Relat Disord 2022; 105:128-131. [PMID: 36434917 DOI: 10.1016/j.parkreldis.2022.11.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/01/2022] [Accepted: 11/07/2022] [Indexed: 11/16/2022]
Abstract
BACKGROUND Hyperekplexia is a disease that progresses with excessive startle attacks and is included in the differential diagnosis of epilepsy and many movement disorders. METHODS The WES results were validated in available family members by Sanger sequencing, or in the case of deletion, PCR followed by agarose gel electrophoresis was performed. RESULTS WES analysis revealed the previously reported homozygous c.277C>T p.Arg93Trp variant in the GLRA1 gene (ENST00000455880.2) in Family 1. In all other three families, the previously reported homozygous deletion of exons 1-7 of the GLRA1 gene was identified using CNV analysis based on the WES data. CONCLUSIONS The homozygous exon1-7 deletion has been described several times in different populations and may be a founder mutation in the Kurdish people in Turkey. The family with Arg93Trp variant stems from the Black Sea region of Turkey where close consanguinity is common. These analyses are important to provide genetic counseling to families and for a better understanding of the pathophysiology of the disease.
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Affiliation(s)
- Didem Tezen
- Istanbul University- Cerrahpasa, Cerrahpasa School of Medicine, Department of Neurology, Istanbul, Turkey.
| | - Gülşah Şimşir
- Suna and İnan Kirac Foundation, Neurodegeneration Research Laboratory, NDAL-KUTTAM, School of Medicine, Koc University, Istanbul, Turkey.
| | - Özlem Çokar
- University of Health Sciences, Haseki Training and Research Hospital, Department of Neurology, Istanbul, Turkey.
| | - Veysi Demirbilek
- Istanbul University- Cerrahpasa, Cerrahpasa School of Medicine, Department of Neurology, Istanbul, Turkey.
| | - A Nazlı Başak
- Suna and İnan Kirac Foundation, Neurodegeneration Research Laboratory, NDAL-KUTTAM, School of Medicine, Koc University, Istanbul, Turkey.
| | - Zuhal Yapıcı
- Istanbul University, Istanbul Faculty of Medicine, Department of Neurology, Istanbul, Turkey.
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Hereditary Hyperekplexia: A New Family and a Systematic Review of GLRA1 Gene-Related Phenotypes. Pediatr Neurol 2022; 132:45-49. [PMID: 35636282 DOI: 10.1016/j.pediatrneurol.2022.05.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 05/05/2022] [Accepted: 05/07/2022] [Indexed: 11/20/2022]
Abstract
Hereditary hyperekplexia (HPX) is a genetic neurodevelopmental disorder recently defined by the triad of (1) neonatal hypertonia, (2) excessive startle reflexes, and (3) generalized stiffness following the startle. Defects in GLRA1 are the most common cause of HPX, inherited both in an autosomal dominant and autosomal recessive manner. GLRA1 mutations can also cause milder phenotypes in the startle syndromes spectrum, but the prevalence is uncertain and no clear genotype-phenotype correlation has emerged yet. Moreover, the prevalence of neurodevelopmental outcomes has not been clearly defined. Here we report a new family of patients with a typical HPX phenotype, linked to a novel GLRA1 mutation, inherited with a recessive pattern. We then perform a systematic review of the literature of GLRA1-related HPX, describing the main epidemiological features of 210 patients. We found that GLRA1-related phenotypes do not necessarily fulfill the current criteria for HPX, including also milder and later-onset phenotypes. Among clinical features of the disease, neurodevelopmental issues were reported in a third of the sample; interestingly, we found that these problems, particularly when severe, were more common in homozygous than in heterozygous patients. Additional clinical and preclinical studies are needed to define predictors of adverse neurodevelopmental outcomes and underlying mechanisms.
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Lagorio I, Brunelli L, Striano P. Paroxysmal Nonepileptic Events in Children: A Video Gallery and a Guide for Differential Diagnosis. Neurol Clin Pract 2022; 12:320-327. [DOI: 10.1212/cpj.0000000000001171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 03/15/2022] [Indexed: 11/15/2022]
Abstract
ABSTRACTPurposeof review Paroxysmal Non-Epileptic Events (PNEEs) are a heterogeneous group of time-limited events, characterized by changes in motor or behavioral activity beginning abruptly and ending in a short time. Due to their manifestation, these conditions can clinically simulate seizures.Recent findings:These episodes belong to different categories including syncopal events, psychiatric disorders, movement disorders, and many others. PNEEs are a common cause of diagnostic mistakes and families’ concerns and the risk of useless and sometimes even injurious treatment is considerable. The high frequency of these manifestations in clinical practice makes PNEEs a diagnostic challenge for clinicians.
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Zhan FX, Wang SG, Cao L. Advances in hyperekplexia and other startle syndromes. Neurol Sci 2021; 42:4095-4107. [PMID: 34379238 DOI: 10.1007/s10072-021-05493-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 07/14/2021] [Indexed: 02/03/2023]
Abstract
Startle, a basic alerting reaction common to all mammals, is described as a sudden involuntary movement of the body evoked by all kinds of sudden and unexpected stimulus. Startle syndromes are heterogeneous groups of disorders with abnormal and exaggerated responses to startling events, including hyperekplexia, stimulus-induced disorders, and neuropsychiatric startle syndromes. Hyperekplexia can be attributed to a genetic, idiopathic, or symptomatic cause. Excluding secondary factors, hereditary hyperekplexia, a rare neurogenetic disorder with highly genetic heterogeneity, is characterized by neonatal hypertonia, exaggerated startle response provoked by the sudden external stimuli, and followed by a short period of general stiffness. It mainly arises from defects of inhibitory glycinergic neurotransmission. GLRA1 is the major pathogenic gene of hereditary hyperekplexia, along with many other genes involved in the function of glycinergic inhibitory synapses. While about 40% of patients remain negative genetic findings. Clonazepam, which can specifically upgrade the GABARA1 chloride channels, is the main and most effective administration for hereditary hyperekplexia patients. In this review, with the aim at enhancing the recognition and prompting potential treatment for hyperekplexia, we focused on discussing the advances in hereditary hyperekplexia genetics and the expound progress in pathogenic mechanisms of the glycinergic-synapse-related pathway and then followed by a brief overview of other common startle syndromes.
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Affiliation(s)
- Fei-Xia Zhan
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yi Shan Road, Shanghai, 200233, China
| | - Shi-Ge Wang
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yi Shan Road, Shanghai, 200233, China
| | - Li Cao
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yi Shan Road, Shanghai, 200233, China.
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Saini AG, Pandey S. Hyperekplexia and other startle syndromes. J Neurol Sci 2020; 416:117051. [PMID: 32721683 DOI: 10.1016/j.jns.2020.117051] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/01/2020] [Accepted: 07/16/2020] [Indexed: 11/18/2022]
Abstract
Abnormal startle syndromes are classified into hyperekplexia, stimulus-induced, and neuropsychiatric startle syndromes. Hyperekplexia is attributed to a genetic, idiopathic, or symptomatic cause. Hereditary hyperekplexia is a treatable neurogenetic disorder. In patients with a hyperactive startle response, the first step is to characterize the extent and associations of 'response.' Secondary or symptomatic causes are particularly important in children, as they provide useful clinical clues to an underlying neurodevelopmental or neurodegenerative disorders. Particular attention should be given to any neonate or infant with generalized or episodic stiffness, drug-refractory seizures, recurrent apnea, stimulus-sensitive behavioral states, or sudden infant death syndrome. Eliciting a non-habituating head-retraction reflex to repeated nose tapping should be a part of routine examination of all new-borns. Vigevano maneuver should be taught to all families and health-care workers as an emergency rescue measure. The onset of excessive startle after infancy should direct investigations for an acquired cause such as brainstem injury, antibodies against glycine receptors, and neurodegeneration. Finally, one should not forget to evaluate unexplained cases of abnormal gait and frequent falls in adults for underlying undiagnosed startle syndromes. Oral clonazepam is an effective therapy besides behavioral and safety interventions for hereditary cases. The outcomes in genetic cases are good overall.
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Affiliation(s)
- Arushi Gahlot Saini
- Department of Pediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India
| | - Sanjay Pandey
- Department of Neurology, Govind Ballabh Pant Institute of Postgraduate medical education and research, JLN Marg, New Delhi 110002, India.
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Zhan F, Zhang C, Wang S, Zhu Z, Chen G, Zhao M, Cao L. Excessive Startle with Novel GLRA1 Mutations in 4 Chinese Patients and a Literature Review of GLRA1-Related Hyperekplexia. J Clin Neurol 2020; 16:230-236. [PMID: 32319239 PMCID: PMC7174104 DOI: 10.3988/jcn.2020.16.2.230] [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: 07/19/2019] [Revised: 10/24/2019] [Accepted: 10/24/2019] [Indexed: 11/17/2022] Open
Abstract
Background and Purpose Hyperekplexia (HPX), a rare neurogenetic disorder, is classically characterized by neonatal hypertonia, exaggerated startle response provoked by the sudden external stimuli and followed by a shortly general stiffness. Glycine receptor alpha 1 (GLRA1) is the major pathogenic gene of the disease. We described the clinical manifestations of genetically confirmed HPX patients and made a literature review of GLRA1-related HPX to improve the early recognition and prompt the management of the disorder. Methods Extensive clinical evaluations were analyzed in 4 Chinese HPX patients from two unrelated families. Next generation sequencing was conducted in the probands. Sanger sequence and segregation analysis were applied to confirm the findings. Results All four patients including 3 males and 1 female presented with excessive startle reflex, a cautious gait and recurrent falls. Moreover, startle episodes were dramatically improved with the treatment of clonazepam in all cases. Exome sequencing revealed 2 homozygous GLRA1 mutations in the patients. The mutation c.1286T>A p.I429N has been previously reported, while c.754delC p.L252* is novel. Conclusions HPX is a treatable disease, and clonazepam is the drug of choice. By studying and reviewing the disorder, we summarized the phenotype, expanded the genotype spectrum, and discussed the possible pathogenic mechanisms to enhance the understanding and recognition of the disease. Early awareness of the disease is crucial to the prompt and proper administration, as well as the genetic counseling.
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Affiliation(s)
- Feixia Zhan
- Department of Neurology, RuiJin Hospital & RuiJin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chao Zhang
- Department of Neurology, Suzhou Hospital Affiliated to Anhui Medical University, Suzhou, China
| | - Shige Wang
- Department of Neurology, RuiJin Hospital & RuiJin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zeyu Zhu
- Department of Neurology, RuiJin Hospital & RuiJin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Guang Chen
- Department of Neurology, RuiJin Hospital & RuiJin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Mingliang Zhao
- Department of Neurology, RuiJin Hospital & RuiJin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Li Cao
- Department of Neurology, RuiJin Hospital & RuiJin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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Zhang Y, Wu LL, Zheng XL, Lin CM. C.292G>A, a novel glycine receptor alpha 1 subunit gene (GLRA1) mutation found in a Chinese patient with hyperekplexia: A case report. Medicine (Baltimore) 2020; 99:e19968. [PMID: 32332682 PMCID: PMC7220787 DOI: 10.1097/md.0000000000019968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
INTRODUCTION Hyperekplexia is a rare hereditary neurological disorder; only 5 glycine receptor alpha 1 subunit gene (GLRA1) mutations have been reported in 5 Chinese patients. We report a Chinese infant with hyperekplexia and a novel mutation at c.292G > A. PATIENT CONCERNS A Chinese infant with hyperekplexia and a novel mutation at c.292G > A. DIAGNOSIS All exons of GLRA1 were sequenced in her parents and her, which revealed a mutation at c.1030C > T and another novel mutation at c.292G > A. Her diagnosis was confirmed as hereditary hyperekplexia with GlRA1 hybrid gene mutations based on the sequencing results. INTERVENTIONS She was treated with clonazepam. OUTCOMES Her muscle hypertonia recovered rapidly and the excessive startle reflex to unexpected stimuli was significantly reduced. CONCLUSION Genetic DNA sequencing is a crucial method for diagnosing hyperekplexia-related gene mutation.
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Antonioni A, Peschi G, Granieri E. A Case of Hyperekplexia That Started From Childhood: Clinical Diagnosis With Negative Genetic Investigations. Front Neurol 2020; 11:10. [PMID: 32116999 PMCID: PMC7026473 DOI: 10.3389/fneur.2020.00010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 01/07/2020] [Indexed: 11/13/2022] Open
Abstract
Here, we report the case of a 63-year-old woman affected by abnormal, excessive, and involuntary reactions to harmless and unexpected sensory stimuli, compatible with the diagnosis of hyperekplexia. It is a pathology that involves the glycinergic system on a hereditary basis, and even if genetic proof compatible with the diagnosis is not present in this case, the fact that an aunt on her father's side suffered from the same disorders supports the clinical suspicion. From an early age, clinical history shows anomalous motor manifestations, initially framed as a form of focal epilepsy or ordinary disorders of the mood sphere, later excluded by the lack of effectiveness of a targeted therapy. Despite this, intellectual, psychological, and socio-emotional development was regular. The manifestations, present throughout childhood, adolescence, and early adulthood in moderate entity, worsened after the age of 50, perhaps due to hormonal changes. The presence of consequent anxiety and depression has compromised her quality of life, and in order to improve it, therapies were resorted, which, however, produced cognitive-attention deficits. No diagnostic exam has confirmed the diagnosis, although some scars in some brain areas involved in the control of reactions are elements favorable to this condition in genetically predisposed subjects. Therapies currently in use attenuate the motor symptomatology without resolving it and cause side effects in the psychological and cognitive sphere. In this case, we want to highlight the difficulty of diagnosing a very rare genetic condition, still not well-known, which presents symptoms easily mistaken for other more common diseases, because there are no specific clinical-diagnostic tools for the time being. In this particular case, we describe a female patient with an atypical onset age and negative genetic investigations compared with what is known in literature regarding this rare disorder. That is why it has been thought she was affected by epilepsy or anxiety-related disorders for several years.
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Affiliation(s)
- Annibale Antonioni
- Section of Neurology, Psychology and Psychiatry, Department of Biomedical and Specialty-Surgical Sciences, University of Ferrara, Ferrara, Italy
| | - Giovanni Peschi
- Department of Interventional, Pediatric and Diagnostic Radiology, Inselspital, University of Bern, Bern, Switzerland
| | - Enrico Granieri
- Section of Neurology, Psychology and Psychiatry, Department of Biomedical and Specialty-Surgical Sciences, University of Ferrara, Ferrara, Italy
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Clinical features and genetic analysis of two siblings with startle disease in an Italian family: a case report. BMC MEDICAL GENETICS 2019; 20:40. [PMID: 30866851 PMCID: PMC6417078 DOI: 10.1186/s12881-019-0779-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 03/06/2019] [Indexed: 12/03/2022]
Abstract
Background Hyperekplexia also known as Startle disease is a rare neuromotor hereditary disorder characterized by exaggerated startle responses to unexpected auditory, tactile, and visual stimuli and generalized muscle stiffness, which both gradually subside during the first months of life. Although the diagnosis of Hyperekplexia is based on clinical findings, pathogenic variants in five genes have been reported to cause Hyperekplexia, of which GLRA1 accounts for about 80% of cases. Dominant and recessive mutations have been identified in GLRA1 gene as pathogenic variants in many individuals with the familial form of Hyperekplexia and occasionally in simplex cases. Case presentation In the present study, we describe clinical and genetic features of two Italian siblings, one with the major and one with the minor form of the disease. DNA samples from the probands and their parents were performed by NGS approach and validated by Sanger sequencing. The analysis of the GLRA1 gene revealed, in both probands, compound heterozygous mutations: c.895C > T or p.R299X inherited from the mother and c.587C > A or p.D98E inherited from the father. Conclusions Until now, these two identified mutations in GLRA1 have not been reported before as compound mutations. What clearly emerges within our study is the clinical heterogeneity in the same family. In fact, even though in the same pedigree, the affected mother showed only mild startle responses to unexpected noise stimuli, which might be explained by variable expressivity, while the father, showed no clear signs of symptomatology, which might be explained by non-penetrance. Finally, the two brothers have different form of the disease, even if the compound heterozygous mutations in GLRA1 are the same, showing that the same mutation in GLRA1 could have different phenotypic expressions and suggesting an underling mechanism of variable expressivity.
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Huang Z, Lian Y, Xu H, Zhang H. Weird Laughing in Hyperekplexia: A new phenotype associated with a novel mutation in the GLRA1 gene? Seizure 2018; 58:6-8. [PMID: 29602144 DOI: 10.1016/j.seizure.2018.03.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 02/17/2018] [Accepted: 03/16/2018] [Indexed: 11/25/2022] Open
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Yang Z, Sun G, Yao F, Tao D, Zhu B. A novel compound mutation in GLRA1 cause hyperekplexia in a Chinese boy- a case report and review of the literature. BMC MEDICAL GENETICS 2017; 18:110. [PMID: 28985719 PMCID: PMC5631533 DOI: 10.1186/s12881-017-0476-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 10/03/2017] [Indexed: 11/10/2022]
Abstract
Background The pathogenesis of hereditary hyperekplexia is thought to involve abnormalities in the glycinergic neurotransmission system, the most of mutations reported in GLRA1. This gene encodes the glycine receptor α1 subunit, which has an extracellular domain (ECD) and a transmembrane domain (TMD) with 4 α-helices (TM1–TM4). Case presentation We investigated the genetic cause of hyperekplexia in a Chinese family with one affected member. Whole-exome sequencing of the 5 candidate genes was performed on the proband patient, and direct sequencing was performed to validate and confirm the detected mutation in other family members. We also review and analyse all reported GLRA1 mutations. The proband had a compound heterozygous GLRA1 mutation that comprised 2 novel GLRA1 missense mutations, C.569C > T (p.T190 M) from the mother and C.1270G > A (p.D424N) from the father. SIFT, Polyphen-2 and MutationTaster analysis identified the mutations as disease-causing, but the parents had no signs of hyperekplexia. The p.T190 M mutation is located in the ECD, while p.D424N is located in TM4. Conclusions Our findings contribute to a growing list GLRA1 mutations associated with hyperekplexia and provide new insights into correlations between phenotype and GLRA1 mutations. Some recessive mutations can induce hyperekplexia in combination with other recessive GLRA1 mutations. Mutations in the ECD, TM1, TM1-TM2 loop, TM3, TM3-TM4 loop and TM4 are more often recessive and part of a compound mutation, while those in TM2 and the TM2-TM3 loop are more likely to be dominant hereditary mutations. Electronic supplementary material The online version of this article (10.1186/s12881-017-0476-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Zhiliang Yang
- Department of Pediatrics, The First Hospital of China Medical University, No. 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China.
| | - Guilian Sun
- Department of Pediatrics, The First Hospital of China Medical University, No. 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Fang Yao
- Department of Pediatrics, The First Hospital of China Medical University, No. 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Dongying Tao
- Department of Pediatrics, The First Hospital of China Medical University, No. 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Binlu Zhu
- Department of Pediatrics, The First Hospital of China Medical University, No. 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China
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