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Zhang Y, Pang D, Wang Z, Ma L, Chen Y, Yang L, Xiao W, Yuan H, Chang F, Ouyang H. An integrative analysis of genotype-phenotype correlation in Charcot Marie Tooth type 2A disease with MFN2 variants: A case and systematic review. Gene 2023; 883:147684. [PMID: 37536398 DOI: 10.1016/j.gene.2023.147684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/24/2023] [Accepted: 07/31/2023] [Indexed: 08/05/2023]
Abstract
Dominant genetic variants in the mitofusin 2 (MFN2) gene lead to Charcot-Marie-Tooth type 2A (CMT2A), a neurodegenerative disease caused by genetic defects that directly damage axons. In this study, we reported a proband with a pathogenic variant in the GTPase domain of MFN2, c.494A > G (p.His165Arg). To date, at least 184 distinct MFN2 variants identified in 944 independent probands have been reported in 131 references. However, the field of medical genetics has long been challenged by how genetic variation in the MFN2 gene is associated with disease phenotypes. Here, by collating the MFN2 variant data and patient clinical information from Leiden Open Variant Database 3.0, NCBI clinvar database, and available related references in PubMed, we determined the mutation frequency, age of onset, sex ratio, and geographical distribution. Furthermore, the results of an analysis examining the relationship between variants and phenotypes from multiple genetic perspectives indicated that insertion and deletions (indels), copy number variants (CNVs), duplication variants, and nonsense mutations in single nucleotide variants (SNVs) tend to be pathogenic, and the results emphasized the importance of the GTPase domain to the structure and function of MFN2. Overall, three reliable classification methods of MFN2 genotype-phenotype associations provide insights into the prediction of CMT2A disease severity. Of course, there are still many MFN2 variants that have not been given clear clinical significance, which requires clinicians to make more accurate clinical diagnoses.
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Affiliation(s)
- Yuanzhu Zhang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Daxin Pang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China; Chongqing Research Institute, Jilin University, Chongqing 401120, China; Chongqing Jitang Biotechnology Research Institute Co., Ltd., Chongqing 401120, China.
| | - Ziru Wang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Lerong Ma
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Yiwu Chen
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Lin Yang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Wenyu Xiao
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Hongming Yuan
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China; Chongqing Research Institute, Jilin University, Chongqing 401120, China.
| | - Fei Chang
- Department of Orthopedics, The Second Hospital of Jilin University, Changchun 130022, China.
| | - Hongsheng Ouyang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Animal Sciences, Jilin University, Changchun 130062, China; Chongqing Research Institute, Jilin University, Chongqing 401120, China; Chongqing Jitang Biotechnology Research Institute Co., Ltd., Chongqing 401120, China.
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Chu F, Xu J, Wang Y, Li Y, Wang Y, Liu Z, Li C. Corrigendum: Novel mutations in GJB1 trigger intracellular aggregation and stress granule formation in X-linked Charcot-Marie-Tooth Disease. Front Neurosci 2023; 17:1282954. [PMID: 37781252 PMCID: PMC10540083 DOI: 10.3389/fnins.2023.1282954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 08/30/2023] [Indexed: 10/03/2023] Open
Abstract
[This corrects the article DOI: 10.3389/fnins.2022.972288.].
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Affiliation(s)
- Fan Chu
- Department of Medical Genetics, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jiaming Xu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yong Wang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yingjie Li
- Department of Medical Genetics, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yaling Wang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhijun Liu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chuanzhou Li
- Department of Medical Genetics, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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3
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Chu F, Xu J, Wang Y, Li Y, Wang Y, Liu Z, Li C. Novel mutations in GJB1 trigger intracellular aggregation and stress granule formation in X-linked Charcot-Marie-Tooth Disease. Front Neurosci 2022; 16:972288. [PMID: 36225735 PMCID: PMC9548587 DOI: 10.3389/fnins.2022.972288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 09/05/2022] [Indexed: 11/16/2022] Open
Abstract
X-linked Charcot-Marie-Tooth Disease type 1(CMT1X) is the second most common form of inherited peripheral neuropathy that is caused by mutations in the gap junction beta-1 (GJB1) gene. Using targeted exome-sequencing, we investigated four CMT families from central-southern China and identified two novel missense variants (p.F31S and p.W44G) and two previously reported variants (p.R220Pfs*23 and p.R164Q) of GJB1. All four probands presented typical early-onset peripheral neuropathy, of which the R220Pfs*23 carrier also had neurologic manifestations in the central nervous system. We then constructed GJB1 expression vectors and performed cell biological analysis in vitro. Expression of FLAG-tagged GJB1 at various time points after transfection revealed evident protein aggregation with both wild-type and mutant forms, indicated with immunostaining and immunoblotting. Detergent-based sequential fractionation confirmed that all mutants were higher expressed and more prone to aggregate than the wild-type, whereas the R220Pfs*23 mutant showed the greatest amount of SDS-soluble multimers and monomers among groups. Moreover, intracellular aggregation probably occurs in the endoplasmic reticulum compartment rather than the Golgi apparatus. Gap junction plaques were present in all groups and were only compromised in frameshift mutant. Further evidence reveals significant intracellular stress granule formation induced by mutated GJB1 and impaired cell viability indicative of cytotoxicity of self-aggregates. Together, our findings demonstrate novel GJB1 variants-induced cell stress and dysfunction and provide insights into understanding the pathomechanisms of GJB1-CMTX1 and other related disorders.
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Affiliation(s)
- Fan Chu
- Department of Medical Genetics, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jiaming Xu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yong Wang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yingjie Li
- Department of Medical Genetics, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yaling Wang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhijun Liu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chuanzhou Li
- Department of Medical Genetics, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Nagappa M, Sharma S, Govindaraj P, Chickabasaviah Y, Siram R, Shroti A, Seshagiri D, Debnath M, Bindu P, Taly A. Genetic spectrum of inherited neuropathies in India. Ann Indian Acad Neurol 2022; 25:407-416. [PMID: 35936615 PMCID: PMC9350795 DOI: 10.4103/aian.aian_269_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 04/29/2022] [Accepted: 04/30/2022] [Indexed: 11/17/2022] Open
Abstract
Background and Objectives: Charcot-Marie-Tooth (CMT) disease is the commonest inherited neuromuscular disorder and has heterogeneous manifestations. Data regarding genetic basis of CMT from India is limited. This study aims to report the variations by using high throughput sequencing in Indian CMT cohort. Methods: Fifty-five probands (M:F 29:26) with suspected inherited neuropathy underwent genetic testing (whole exome: 31, clinical exome: 17 and targeted panel: 7). Their clinical and genetic data were analysed. Results: Age at onset ranged from infancy to 54 years. Clinical features included early-onset neuropathy (n=23), skeletal deformities (n=45), impaired vision (n=8), impaired hearing (n=6), facial palsy (n=8), thickened nerves (n=4), impaired cognition (n=5), seizures (n=5), pyramidal signs (n=7), ataxia (n=8) and vocal cord palsy, slow tongue movements and psychosis in one patient each. Twenty-eight patients had demyelinating electrophysiology. Abnormal visual and auditory evoked potentials were noted in 60.60% and 37.5% respectively. Sixty two variants were identified in 37 genes including variants of uncertain significance (n=34) and novel variants (n=45). Eleven patients had additional variations in genes implicated in CMTs/ other neurological disorders. Ten patients did not have variations in neuropathy associated genes, but had variations in genes implicated in other neurological disorders. In seven patients, no variations were detected. Conclusion: In this single centre cohort study from India, genetic diagnosis could be established in 87% of patients with inherited neuropathy. The identified spectrum of genetic variations adds to the pool of existing data and provides a platform for validation studies in cell culture or animal model systems.
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Dong HL, Ma Y, Yu H, Wei Q, Li JQ, Liu GL, Li HF, Chen L, Chen DF, Bai G, Wu ZY. Bi-allelic loss of function variants in COX20 gene cause autosomal recessive sensory neuronopathy. Brain 2021; 144:2457-2470. [PMID: 33751098 DOI: 10.1093/brain/awab135] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 01/18/2021] [Accepted: 01/30/2021] [Indexed: 12/24/2022] Open
Abstract
Sensory neuronopathies are a rare and distinct subgroup of peripheral neuropathies, characterized by degeneration of the dorsal root ganglia neurons. About 50% of sensory neuronopathies are idiopathic and genetic causes remain to be clarified. Through a combination of homozygosity mapping and whole exome sequencing, we linked an autosomal recessive sensory neuronopathy to pathogenic variants in COX20 gene. We identified 8 unrelated families from the eastern China population carrying a founder variant c.41A>G (p. Lys14Arg) within COX20 in either a homozygous or compound heterozygous state. All patients displayed sensory ataxia with non-length-dependent sensory potentials decrease. COX20 encodes a key transmembrane protein implicated in the assembly of mitochondrial complex IV. We showed that COX20 variants lead to reduction of COX20 protein in patient's fibroblasts and transfected cell lines, consistent with a loss-of-function mechanism. Knockdown of COX20 expression in ND7/23 sensory neuron cells resulted in complex IV deficiency and perturbed assembly of complex IV, which subsequently compromised cell spare respiratory capacity and reduced cell proliferation under metabolic stress. Consistent with mitochondrial dysfunction in knockdown cells, reduced complex IV assembly, enzyme activity and oxygen consumption rate were also found in patients' fibroblasts. We speculated that the mechanism of COX20 was similar to other causative genes (e.g. SURF1, COX6A1, COA3 and SCO2) for peripheral neuropathies, all of which were functionally important in the structure and assembly of complex IV. Our study identifies a novel causative gene for the autosomal recessive sensory neuronopathy, whose vital function in complex IV and high expression in the proprioceptive sensory neuron further underlines loss of COX20 contributing to mitochondrial bioenergetic dysfunction as a mechanism in peripheral sensory neuron disease.
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Affiliation(s)
- Hai-Lin Dong
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, Hangzhou, China
| | - Yin Ma
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, Hangzhou, China
| | - Hao Yu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, Hangzhou, China
| | - Qiao Wei
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, Hangzhou, China
| | - Jia-Qi Li
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, Hangzhou, China
| | - Gong-Lu Liu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, Hangzhou, China
| | - Hong-Fu Li
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, Hangzhou, China
| | - Lei Chen
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, Hangzhou, China.,Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Dian-Fu Chen
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, Hangzhou, China.,Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Ge Bai
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, Hangzhou, China.,Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Zhi-Ying Wu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, Hangzhou, China.,Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai, China
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Dong H, Wei Q, Li J, Li H, Bai G, Ma H, Wu Z. Genetic spectrum of
MCM3AP
and its relationship with phenotype of
Charcot‐Marie‐Tooth
disease. J Peripher Nerv Syst 2020; 25:107-111. [PMID: 32319184 DOI: 10.1111/jns.12377] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/14/2020] [Accepted: 04/15/2020] [Indexed: 12/11/2022]
Affiliation(s)
- Hai‐Lin Dong
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang ProvinceZhejiang University School of Medicine Hangzhou China
| | - Qiao Wei
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang ProvinceZhejiang University School of Medicine Hangzhou China
| | - Jia‐Qi Li
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang ProvinceZhejiang University School of Medicine Hangzhou China
| | - Hong‐Fu Li
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang ProvinceZhejiang University School of Medicine Hangzhou China
| | - Ge Bai
- Institute of Neuroscience and Key Laboratory of Medical Neurobiology of Zhejiang ProvinceZhejiang University School of Medicine Hangzhou China
| | - Huan Ma
- Institute of Neuroscience and Key Laboratory of Medical Neurobiology of Zhejiang ProvinceZhejiang University School of Medicine Hangzhou China
| | - Zhi‐Ying Wu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang ProvinceZhejiang University School of Medicine Hangzhou China
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Michaelidou K, Tsiverdis I, Erimaki S, Papadimitriou D, Amoiridis G, Papadimitriou A, Mitsias P, Zaganas I. Whole exome sequencing establishes diagnosis of Charcot-Marie-Tooth 4J, 1C, and X1 subtypes. Mol Genet Genomic Med 2020; 8:e1141. [PMID: 32022442 PMCID: PMC7196464 DOI: 10.1002/mgg3.1141] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 01/01/2020] [Accepted: 01/03/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Charcot-Marie-Tooth (CMT) hereditary polyneuropathies pose a diagnostic challenge. Our aim here is to describe CMT patients diagnosed by whole exome sequencing (WES) following years of fruitless testing. METHODS/RESULTS Three patients with polyneuropathy suspected to be genetic in origin, but not harboring PMP22 gene deletion/duplication, were offered WES. The first patient, a 66-year-old man, had been suffering from progressive weakness and atrophies in the lower and upper extremities for 20 years. Due to ambiguous electrophysiological findings, immune therapies were administered to no avail. Twelve years after PMP22 deletion/duplication testing, WES revealed two pathogenic variants in the FIG4 gene (p.Ile41Thr and p.Phe598fs, respectively), as a cause of CMT 4J. The second patient, a 19-year-old man, had been suffering from hearing and gait impairment since at least his infancy, and recently presented with weakness and dystonia of the lower extremities. In this patient, WES identified the p.Leu122Val LITAF gene variant in heterozygous state, suggesting the diagnosis of CMT 1C, several years after initial genetic analyses. The third patient, a 44-year-old man, presented with progressive weakness and atrophies of the lower and upper extremities since the age of 17 years old. In this patient, WES identified the hemizygous p.Arg164Gln pathogenic variant in the GJB1 gene, establishing the diagnosis of CMT X1, 8 years after testing for PMP22 deletion/duplication. CONCLUSION Novel diagnostic techniques, such as WES, offer the possibility to decipher the cause of CMT subtypes, ending the diagnostic Odyssey of the patients and sparing them from unnecessary and potentially harmful treatments.
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Affiliation(s)
- Kleita Michaelidou
- Neurogenetics LaboratoryMedical SchoolUniversity of CreteHeraklion, CreteGreece
| | - Ioannis Tsiverdis
- Neurology DepartmentUniversity Hospital of CreteHeraklion, CreteGreece
| | - Sophia Erimaki
- Neurophysiology UnitUniversity Hospital of CreteHeraklion, CreteGreece
| | | | | | | | - Panayiotis Mitsias
- Neurogenetics LaboratoryMedical SchoolUniversity of CreteHeraklion, CreteGreece
- Neurology DepartmentUniversity Hospital of CreteHeraklion, CreteGreece
- Neurophysiology UnitUniversity Hospital of CreteHeraklion, CreteGreece
- Department of NeurologyHenry Ford Hospital/Wayne State UniversityDetroitMIUSA
| | - Ioannis Zaganas
- Neurogenetics LaboratoryMedical SchoolUniversity of CreteHeraklion, CreteGreece
- Neurology DepartmentUniversity Hospital of CreteHeraklion, CreteGreece
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He J, Lin H, Li JJ, Su HZ, Wang DN, Lin Y, Wang N, Chen WJ. Identification of a Novel Homozygous Splice-Site Mutation in SCARB2 that Causes Progressive Myoclonus Epilepsy with or without Renal Failure. Chin Med J (Engl) 2018; 131:1575-1583. [PMID: 29941711 PMCID: PMC6032684 DOI: 10.4103/0366-6999.235113] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Progressive myoclonus epilepsies (PMEs) comprise a group of rare genetic disorders characterized by action myoclonus, epileptic seizures, and ataxia with progressive neurologic decline. Due to clinical and genetic heterogeneity of PMEs, it is difficult to decide which genes are affected. The aim of this study was to report an action myoclonus with or without renal failure syndrome (EPM4) family and summarize the clinical and genetic characteristics of all reported EPM4 patients. METHODS In the present study, targeted next-generation sequencing (NGS) was applied to screen causative genes in a Chinese PME family. The candidate variant was further confirmed by cosegregation analysis and further functional analysis, including the reverse transcription polymerase chain reaction and Western blot of the proband's muscle. Moreover, literature data on the clinical and mutational features of all reported EPM4 patients were reviewed. RESULTS The gene analysis revealed a novel homozygous splicing mutation (c.995-1G>A) of the SCARB2 gene in two brothers. Further functional analysis revealed that this mutation led to loss function of the SCARB2 protein. The classification of the candidate variant, according to the American College of Medical Genetics and Genomics standards and guidelines and functional analysis, was pathogenic. Therefore, these two brothers were finally diagnostically confirmed as EPM4. CONCLUSIONS These present results suggest the potential for targeted NGS to conduct a more rapid and precise diagnosis for PME patients. A literature review revealed that mutations in the different functional domains of SCARB2 appear to be associated with the phenotype of EPM4.
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Affiliation(s)
- Jin He
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350005, China
| | - Han Lin
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350005, China
| | - Jin-Jing Li
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350005, China
| | - Hui-Zhen Su
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350005, China
| | - Dan-Ni Wang
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350005, China
| | - Yu Lin
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350005, China
- Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, Fujian 350005, China
| | - Ning Wang
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350005, China
- Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, Fujian 350005, China
| | - Wan-Jin Chen
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350005, China
- Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, Fujian 350005, China
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Li LX, Dong HL, Xiao BG, Wu ZY. A Novel Missense Mutation in Peripheral Myelin Protein-22 Causes Charcot-Marie-Tooth Disease. Chin Med J (Engl) 2018; 130:1779-1784. [PMID: 28748849 PMCID: PMC5547828 DOI: 10.4103/0366-6999.211539] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Background: Charcot-Marie-Tooth disease (CMT) is the most common inherited peripheral neuropathy. A great number of causative genes have been described in CMT, and among them, the heterozygous duplication of peripheral myelin protein-22 (PMP22) is the major cause. Although the missense mutation in PMP22 is rarely reported, it has been demonstrated to be associated with CMT. This study described a novel missense mutation of PMP22 in a Chinese family with CMT phenotype. Methods: Targeted next-generation sequencing (NGS) was used to screen the causative genes in a family featured with an autosomal dominant demyelinating form of CMT. The potential variants identified by targeted NGS were verified by Sanger sequencing and classified according to the American College of Medical Genetics and Genomics standards and guidelines. Further cell transfection studies were performed to characterize the function of the novel variant. Results: Using targeted NGS, a novel heterozygous missense variant in PMP22 (c.320G>A, p.G107D) was identified. In vitro cell functional studies revealed that mutant PMP22 protein carrying p.G107D mutation lost the ability to reach the plasma membrane, was mainly retained in the endoplasmic reticulum, and induced cell apoptosis. Conclusions: This study supported the notion that missense mutations in PMP22 give rise to a CMT phenotype, possibly through a toxic gain-of-function mechanism.
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Affiliation(s)
- Li-Xi Li
- Department of Neurology and Institute of Neurology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai 200040, China
| | - Hai-Lin Dong
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, The Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, China
| | - Bao-Guo Xiao
- Department of Neurology and Institute of Neurology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai 200040, China
| | - Zhi-Ying Wu
- Department of Neurology and Institute of Neurology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai 200040, China
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10
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Chen B, Niu S, Wang X, Li W, Chen N, Zhang Z. Clinical, electrophysiological, genetic, and imaging features of six Chinese Han patients with hereditary neuropathy with liability to pressure palsies (HNPP). J Clin Neurosci 2017; 48:133-137. [PMID: 29108667 DOI: 10.1016/j.jocn.2017.10.069] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 10/14/2017] [Accepted: 10/22/2017] [Indexed: 10/18/2022]
Abstract
Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant peripheral neuropathy caused by mutations in the peripheral myelin protein 22 (PMP22) gene. This study summarizes the clinical, electrophysiological, genetic, and imaging features of six unrelated Chinese Han patients with HNPP. Age of onset was within the second decade in five patients, and 46 years of age in one patient. Weakness or numbness in a unilateral lower extremity was the most common symptom in 5 patients, and bilateral sensorineural hearing loss was also detected in one patient. Electrophysiological presentations suggested demyelinating sensory-motor polyneuropathy in the group. Magnetic resonance imaging (MRI) of the cervical and lumbar spine revealed varying degrees of degeneration in five patients, and mild kyphosis of cervical vertebral bodies in 2 teen-aged patients. In addition, cranial MRI of one patient showed scattered demyelination in the frontal lobes. Targeted next-generation-sequencing (NGS) revealed a PMP22 deletion in five patients and a heterozygous c.199G>A mutation in exon 4 of PMP22 in one patient. The I92V variant of lipopolysaccharide-induced tumor necrosis factor (LITAF) gene was found in one patient. There was no relationship between the Ile92Val variant of LITAF and age of onset in this group, albeit the sample size was very small.
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Affiliation(s)
- Bin Chen
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, China National Clinical Research Center for Neurological Diseases, Beijing 100050, China
| | - Songtao Niu
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, China National Clinical Research Center for Neurological Diseases, Beijing 100050, China
| | - Xingao Wang
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, China National Clinical Research Center for Neurological Diseases, Beijing 100050, China
| | - Wei Li
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, China National Clinical Research Center for Neurological Diseases, Beijing 100050, China
| | - Na Chen
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, China National Clinical Research Center for Neurological Diseases, Beijing 100050, China
| | - Zaiqiang Zhang
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, China National Clinical Research Center for Neurological Diseases, Beijing 100050, China.
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11
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Li LX, Liu GL, Liu ZJ, Lu C, Wu ZY. Identification and functional characterization of two missense mutations in NDRG1 associated with Charcot-Marie-Tooth disease type 4D. Hum Mutat 2017; 38:1569-1578. [PMID: 28776325 DOI: 10.1002/humu.23309] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 06/27/2017] [Accepted: 07/30/2017] [Indexed: 11/10/2022]
Abstract
Charcot-Marie-Tooth disease type 4D (CMT4D) is an autosomal-recessive demyelinating form of CMT characterized by a severe distal motor and sensory neuropathy. NDRG1 is the causative gene for CMT4D. To date, only four mutations in NDRG1 -c.442C>T (p.Arg148*), c.739delC (p.His247Thrfs*74), c.538-1G>A, and duplication of exons 6-8-have been described in CMT4D patients. Here, using targeted next-generation sequencing examination, we identified for the first time two homozygous missense variants in NDRG1, c.437T>C (p.Leu146Pro) and c.701G>A (p.Arg234Gln), in two Chinese CMT families with consanguineous histories. Further functional studies were performed to characterize the biological effects of these variants. Cell culture transfection studies showed that mutant NDRG1 carrying p.Leu146Pro, p.Arg148*, or p.Arg234Gln variant degraded faster than wild-type NDRG1, resulting in lower protein levels. Live cell confocal microscopy and coimmunoprecipitation analysis indicated that these variants did not disrupt the interaction between NDRG1 and Rab4a protein. However, NDRG1-knockdown cells expressing mutant NDRG1 displayed enlarged Rab4a-positive compartments. Moreover, mutant NDRG1 could not enhance the uptake of DiI-LDL or increase the fraction of low-density lipoprotein receptor on the cell surface. Taken together, our study described two missense mutations in NDRG1 and emphasized the important role of NDRG1 in intracellular protein trafficking.
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Affiliation(s)
- Li-Xi Li
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology and Institute of Neurology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Gong-Lu Liu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhi-Jun Liu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology and Institute of Neurology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Cong Lu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhi-Ying Wu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China
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Lu YY, Lyu H, Jin SQ, Zuo YH, Liu J, Wang ZX, Zhang W, Yuan Y. Clinical and Genetic Features of Chinese X-linked Charcot-Marie-Tooth Type 1 Disease. Chin Med J (Engl) 2017; 130:1049-1054. [PMID: 28469099 PMCID: PMC5421174 DOI: 10.4103/0366-6999.204925] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND X-linked Charcot-Marie-Tooth type 1 (CMT1X) disease is one of the most common forms of inherited neuropathy caused by mutations in the gap junction beta-1 protein (GJB1) gene (also known as connexin 32). This study presented the clinical and genetic features of a series of Chinese patients with GJB1 gene mutations. METHODS A total of 22 patients from unrelated families, who were referred to Department of Neurology, Peking University First Hospital from January 2005 to January 2016, were identified with GJB1 mutations. Their clinical records and laboratory findings were retrospectively collected and reviewed. Mutations in the GJB1 gene were analyzed by targeted next-generation sequencing (NGS). Nucleotide alternations were confirmed with Sanger sequencing. RESULTS The CMT1X patients predominantly showed distal muscle weakness of lower limbs with mild sensory disturbance. The mean age of onset was 15.6 ± 8.7 years (ranging from 1 year to 42 years). The sudden onset of cerebral symptoms appeared in four patients (18.2%); two were initial symptoms. One case had constant central nervous system (CNS) signs. There were 19 different heterozygous mutations, including 15 known mutations and four novel mutations (c.115G>T, c.380T>A, c.263C>A, and c.818_819insGGGCT). Among the 22 Chinese patients with CMT1X, the frequency of the GJB1 mutation was 4.5% in transmembrane domain 1 (TM1), 4.5% in TM2, 22.7% in TM3, 9.1% in TM4, 4.5% in extracellular 1 (EC1), 27.3% in EC2, 9.1% in intracellular loop, 13.6% in the N-terminal domain, and 4.5% in the C-terminal domain. CMT1X with CNS impairment appeared in five (22.7%) of these patients. CONCLUSIONS This study indicated that CNS impairment was not rare in Chinese CMT1X patients. Mutations in the EC2 domain of the GJB1 gene were hotspot in Chinese CMT1X patients.
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Affiliation(s)
- Yuan-Yuan Lu
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
| | - He Lyu
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
| | - Su-Qin Jin
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
| | - Yue-Huan Zuo
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
| | - Jing Liu
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
| | - Zhao-Xia Wang
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
| | - Wei Zhang
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
| | - Yun Yuan
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
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13
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Lu C, Zheng YC, Dong Y, Li HF. Identification of novel senataxin mutations in Chinese patients with autosomal recessive cerebellar ataxias by targeted next-generation sequencing. BMC Neurol 2016; 16:179. [PMID: 27644330 PMCID: PMC5029030 DOI: 10.1186/s12883-016-0696-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 09/07/2016] [Indexed: 11/21/2022] Open
Abstract
Background Autosomal recessive cerebellar ataxias (ARCA) are a group of neurodegenerative disorders characterized by early onset of gait impairment, disturbed limb coordination, dysarthria, and eye movement abnormalities, most likely due to the degeneration of cerebellum, brainstem, and spinal cord. Despite of the rarity, ARCA are both clinically and genetically heterogeneous. To date, more than 30 culprit genes have been identified in ARCA. Unraveling the specific causative mutation in cases with ARCA remains challenging so far. Methods Three ARCA pedigrees of Chinese ancestry were recruited. Clinical features were evaluated and peripheral blood was collected after obtaining the written inform. Laboratory examinations, brain MRI, and EMG were performed for all the affected individuals. Genomic DNA was extracted, followed by the screening of GAA repeat expansion in FXN gene to exclude Friedreich’s ataxia. Targeted next-generation sequencing combining Sanger sequencing was performed in each proband of these families. Results Compound heterozygous mutations, c.3190G > T (p.E1064X) and c.4883C > G (p.S1628X) of senataxin (SETX) gene were identified in one family with two affected cases. Both of the patients presented with early onset of unsteady walk, dysarthria, and diplopia. EMG test revealed decreased conduction velocity and evoked potential of both motor and sensory nerve. Moreover, elevated serum alpha-fetoprotein (AFP) and apparent cerebellar atrophy were observed. These features were typical features of ataxia with oculomotor apraxia type 2 (AOA2) and in line with the genetic results. However, no specific mutation was identified in the other two pedigrees. Conclusions We identified novel compound heterozygous mutations of SETX in Chinese AOA2 pedigree, which broaden the mutation spectrum of SETX. To our knowledge, this is the first report concerning Chinese AOA2 cases with SETX mutations. Electronic supplementary material The online version of this article (doi:10.1186/s12883-016-0696-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Cong Lu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009, China.,Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Yi-Cen Zheng
- The High School Affiliated to Fudan University-WLSA Fudan Academy, Shanghai, China
| | - Yi Dong
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009, China
| | - Hong-Fu Li
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009, China.
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