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He W, Meng G, Hu X, Dai J, Liu J, Li X, Hu H, Tan Y, Zhang Q, Lu G, Lin G, Du J. Reclassification of DMD Duplications as Benign: Recommendations for Cautious Interpretation of Variants Identified in Prenatal Screening. Genes (Basel) 2022; 13:1972. [PMID: 36360209 PMCID: PMC9690433 DOI: 10.3390/genes13111972] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/1970] [Revised: 10/15/2022] [Accepted: 10/26/2022] [Indexed: 09/09/2023] Open
Abstract
Duplications are the main type of dystrophin gene (DMD) variants, which typically cause dystrophinopathies such as Duchenne muscular dystrophy and Becker muscular dystrophy. Maternally inherited exon duplication in DMD in fetuses is a relatively common finding of genetic screening in clinical practice. However, there is no standard strategy for interpretation of the pathogenicity of DMD duplications during prenatal screening, especially for male fetuses, in which maternally inherited pathogenic DMD variants more frequently cause dystrophinopathies. Here, we report three non-contiguous DMD duplications identified in a woman and her male fetus during prenatal screening. Multiplex ligation probe amplification and long-read sequencing were performed on the woman and her family members to verify the presence of DMD duplications. Structural rearrangements in the DMD gene were mapped by long-read sequencing, and the breakpoint junction sequences were validated using Sanger sequencing. The woman and her father carried three non-contiguous DMD duplications. Long-read and Sanger sequencing revealed that the woman's father carried an intact DMD copy and a complex structural rearrangement of the DMD gene. Therefore, we reclassified these three non-contiguous DMD duplications, one of which is listed as pathogenic, as benign. We postulate that breakpoint analysis should be performed on identified DMD duplication variants, and the pathogenicity of the duplications found during prenatal screening should be interpreted cautiously for clinical prediction and genetic/reproductive counseling.
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Affiliation(s)
- Wenbin He
- Institute of Reproductive and Stem Cell Engineering, NHC Key Laboratory of Human Stem Cell and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha 410008, China
- National Engineering and Research Center of Human Stem Cells, Changsha 410006, China
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha 410008, China
| | - Guiquan Meng
- Institute of Reproductive and Stem Cell Engineering, NHC Key Laboratory of Human Stem Cell and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha 410008, China
| | - Xiao Hu
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha 410008, China
| | - Jing Dai
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha 410008, China
| | - Jiyang Liu
- Changsha Health Committee, Changsha 410006, China
| | - Xiurong Li
- Institute of Reproductive and Stem Cell Engineering, NHC Key Laboratory of Human Stem Cell and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha 410008, China
- National Engineering and Research Center of Human Stem Cells, Changsha 410006, China
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha 410008, China
| | - Hao Hu
- National Engineering and Research Center of Human Stem Cells, Changsha 410006, China
| | - Yueqiu Tan
- Institute of Reproductive and Stem Cell Engineering, NHC Key Laboratory of Human Stem Cell and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha 410008, China
- National Engineering and Research Center of Human Stem Cells, Changsha 410006, China
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha 410008, China
| | - Qianjun Zhang
- Institute of Reproductive and Stem Cell Engineering, NHC Key Laboratory of Human Stem Cell and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha 410008, China
- National Engineering and Research Center of Human Stem Cells, Changsha 410006, China
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha 410008, China
| | - Guangxiu Lu
- Institute of Reproductive and Stem Cell Engineering, NHC Key Laboratory of Human Stem Cell and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha 410008, China
- National Engineering and Research Center of Human Stem Cells, Changsha 410006, China
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha 410008, China
| | - Ge Lin
- Institute of Reproductive and Stem Cell Engineering, NHC Key Laboratory of Human Stem Cell and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha 410008, China
- National Engineering and Research Center of Human Stem Cells, Changsha 410006, China
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha 410008, China
| | - Juan Du
- Institute of Reproductive and Stem Cell Engineering, NHC Key Laboratory of Human Stem Cell and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha 410008, China
- National Engineering and Research Center of Human Stem Cells, Changsha 410006, China
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha 410008, China
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Moss KR, Bopp TS, Johnson AE, Höke A. New evidence for secondary axonal degeneration in demyelinating neuropathies. Neurosci Lett 2021; 744:135595. [PMID: 33359733 PMCID: PMC7852893 DOI: 10.1016/j.neulet.2020.135595] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 10/31/2020] [Accepted: 12/19/2020] [Indexed: 12/28/2022]
Abstract
Development of peripheral nervous system (PNS) myelin involves a coordinated series of events between growing axons and the Schwann cell (SC) progenitors that will eventually ensheath them. Myelin sheaths have evolved out of necessity to maintain rapid impulse propagation while accounting for body space constraints. However, myelinating SCs perform additional critical functions that are required to preserve axonal integrity including mitigating energy consumption by establishing the nodal architecture, regulating axon caliber by organizing axonal cytoskeleton networks, providing trophic and potentially metabolic support, possibly supplying genetic translation materials and protecting axons from toxic insults. The intermediate steps between the loss of these functions and the initiation of axon degeneration are unknown but the importance of these processes provides insightful clues. Prevalent demyelinating diseases of the PNS include the inherited neuropathies Charcot-Marie-Tooth Disease, Type 1 (CMT1) and Hereditary Neuropathy with Liability to Pressure Palsies (HNPP) and the inflammatory diseases Acute Inflammatory Demyelinating Polyneuropathy (AIDP) and Chronic Inflammatory Demyelinating Polyneuropathy (CIDP). Secondary axon degeneration is a common feature of demyelinating neuropathies and this process is often correlated with clinical deficits and long-lasting disability in patients. There is abundant electrophysiological and histological evidence for secondary axon degeneration in patients and rodent models of PNS demyelinating diseases. Fully understanding the involvement of secondary axon degeneration in these diseases is essential for expanding our knowledge of disease pathogenesis and prognosis, which will be essential for developing novel therapeutic strategies.
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Affiliation(s)
- Kathryn R Moss
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Taylor S Bopp
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Anna E Johnson
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Ahmet Höke
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States.
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Asadchuk TV, Rumiantseva NV, Naumchik IV, Likhachev SA, Pleshko IV, Shalkevich LV, Jevneronok IV, Kachan JP. [Molecular genetic diagnosis and clinical features of hereditary neuropathy with liability to pressure palsies in Belarusian patients]. Zh Nevrol Psikhiatr Im S S Korsakova 2016; 116:64-69. [PMID: 26977628 DOI: 10.17116/jnevro20161161164-69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To analyze the molecular defect, a phenotype of hereditary neuropathy with liability to pressure palsies (HNPP, OMIM 162500), in patients with PMP22 gene mutation caused by 1.5 Mb deletion at 17p11.2. and present the principles of diagnosis and genetic counselling. MATERIAL AND METHODS Patients were selected on the basis of the results of the clinical/genealogical analysis, neurological examination and ENMG study. Genomic DNA was isolated from peripheral blood leukocytes. RESULTS AND CONCLUSION DNA diagnosis was performed in 5 families (the PMP22 deletion was found in 9 patients). The authors described clinical and electrophysiological characteristics and presented a diagnostic protocol. Identification of the mutation makes it possible to confirm the clinical diagnosis, assess genetic risks for the outcome and perform a prenatal DNA diagnosis in HNPP families.
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Affiliation(s)
- T V Asadchuk
- Republican Scientific and Practical Medical Center 'Mother and Child', Minsk, Belarus
| | - N V Rumiantseva
- Republican Scientific and Practical Medical Center 'Mother and Child', Minsk, Belarus
| | - I V Naumchik
- Republican Scientific and Practical Medical Center 'Mother and Child', Minsk, Belarus
| | - S A Likhachev
- Republican Scientific and Practical Center of Neurology and Neurosurgery, Minsk, Belarus
| | - I V Pleshko
- Republican Scientific and Practical Center of Neurology and Neurosurgery, Minsk, Belarus
| | - L V Shalkevich
- Belorussian Medical Academy of Post-Graduate Education, Minsk, Belarus
| | - I V Jevneronok
- Belorussian Medical Academy of Post-Graduate Education, Minsk, Belarus
| | - J P Kachan
- Republican Scientific and Practical Medical Center 'Mother and Child', Minsk, Belarus
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Wang R, He J, Li JJ, Ni W, Wu ZY, Chen WJ, Wang Y. Clinical and genetic spectra in a series of Chinese patients with Charcot-Marie-Tooth disease. Clin Chim Acta 2015; 451:263-70. [PMID: 26454100 DOI: 10.1016/j.cca.2015.10.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 10/05/2015] [Accepted: 10/06/2015] [Indexed: 12/27/2022]
Abstract
The aim of this study was to determine the clinical features and frequencies of genetic subtypes in a series of patients with Charcot-Marie-Tooth (CMT) disease from Eastern China. Patients were divided into three subtypes, CMT1, CMT2 and hereditary neuropathy with liability to pressure palsy (HNPP), according to their electrophysiological manifestations. Multiplex ligation-dependent probe analysis (MLPA) was performed to detect duplications/deletions in the PMP22 gene. The coding regions and splice sites of the GJB1, MPZ, MFN2 and GDAP-1 genes were determined by direct sequencing. Among the 148 patients in the study, 37.2% of the cases had mutations in genes assessed. The mutation detection rate was higher in patients with family histories than in spontaneous cases. PMP22 duplication (13.5%) was predominant in this group of patients, followed by PMP22 deletion (11.5%), and point mutations in GJB1 (8.8%), MPZ (2.0%) and MFN2 (0.7%). Three novel mutations (c.151T>C and c.310 A>G in GJB1 and c.1516 C>G in MFN2) were detected. A small deletion in PMP22 exon 4 was detected in a patient with severe CMT1. Genetic tests have great value in CMT patients with family histories. The frequency of PMP22 duplications was lower in Asian patients than in others. We suggest that genetic testing strategies in CMT patients should be primarily based on electromyography data.
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Affiliation(s)
- Rui Wang
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China; Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Jin He
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, China; Fujian Key Laboratory of Molecular Neurology, Fuzhou, China
| | - Jin-Jing Li
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Wang Ni
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China; Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Zhi-Ying Wu
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China
| | - Wan-Jin Chen
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, China; Fujian Key Laboratory of Molecular Neurology, Fuzhou, China
| | - Yi Wang
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China.
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Wedderburn S, Pateria P, Panegyres PK. Hereditary Neuropathy with Liability to Pressure Palsy Presenting as an Acute Brachial Plexopathy: A Lover's Palsy. Case Rep Neurol 2014; 6:281-6. [PMID: 25685136 PMCID: PMC4296227 DOI: 10.1159/000369921] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
It is generally regarded that patients with hereditary neuropathy to pressure palsies, due to a deletion in the PMP22 gene, show recurrent pressure palsy and generalised peripheral neuropathy (pes cavus and hammer toes sometimes develop). Brachial plexopathy is rarely identified as a first presentation of hereditary neuropathy to pressure palsies. We describe a young man who developed a painless flail upper limb with a clinical diagnosis of a brachial plexopathy after his partner slept on his arm – a PMP22 deletion was found. His father, who had a symmetrical polyneuropathy without recurrent mononeuropathies, shared the PMP22 deletion.
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Affiliation(s)
- Sarah Wedderburn
- Neurodegenerative Disorders Research Pty. Ltd., West Perth, W.A., Australia
| | - Puraskar Pateria
- Neurology Unit, Joondalup Health Campus, Joondalup, W.A., Australia
| | - Peter K Panegyres
- Neurodegenerative Disorders Research Pty. Ltd., West Perth, W.A., Australia ; Neurology Unit, Joondalup Health Campus, Joondalup, W.A., Australia
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