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Zhang B, Gang Q, Meng L, Li Z, Chu X, Wu H, Yang J, Huang B, Du K. A novel variant of biallelic MME gene associated with autosomal recessive late-onset distal hereditary motor neuropathy in Chinese families. BMC Med Genomics 2024; 17:223. [PMID: 39232784 PMCID: PMC11373294 DOI: 10.1186/s12920-024-01996-3] [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: 04/02/2024] [Accepted: 08/21/2024] [Indexed: 09/06/2024] Open
Abstract
Distal hereditary motor neuropathies (dHMN) are a group of heterogeneous diseases and previous studies have reported that the compound heterozygous recessive MME variants cause dHMN. Our study found a novel homozygous MME variant and a reported compound heterozygous MME variant in two Chinese families, respectively. Next-generation sequencing and nerve conduction studies were performed for two probands. The probands in two families presented with the muscle weakness and wasting of both lower limbs and carried a c.2122 A > T (p.K708*) and c.1342 C > T&c.2071_2072delinsTT (p.R448*&p.A691L) variant, respectively. Prominently axonal impairment of motor nerves and slight involvement of sensory nerves were observed in nerve conduction study. Our study reported a "novel" nonsense mutation and a missense variant of autosomal recessive late-onset dHMN and reviewed reported MME variants associated with dHMN phenotype.
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Affiliation(s)
- Bentuo Zhang
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Qiang Gang
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Lingchao Meng
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Zhenyu Li
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Xujun Chu
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Haohao Wu
- Department of Neurology, Qujing First People's Hospital, Yunnan, 655000, Qujing, China
| | - Junsu Yang
- Department of Neurology, Qujing First People's Hospital, Yunnan, 655000, Qujing, China
| | - Baogang Huang
- Department of Neurology, Qujing First People's Hospital, Yunnan, 655000, Qujing, China.
| | - Kang Du
- Department of Neurology, Qujing First People's Hospital, Yunnan, 655000, Qujing, China.
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Grosz BR, Parmar JM, Ellis M, Bryen S, Simons C, Reis ALM, Stevanovski I, Deveson IW, Nicholson G, Laing N, Wallis M, Ravenscroft G, Kumar KR, Vucic S, Kennerson ML. A deep intronic variant in MME causes autosomal recessive Charcot-Marie-Tooth neuropathy through aberrant splicing. J Peripher Nerv Syst 2024; 29:262-274. [PMID: 38860315 DOI: 10.1111/jns.12637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 05/26/2024] [Accepted: 05/28/2024] [Indexed: 06/12/2024]
Abstract
BACKGROUND Loss-of-function variants in MME (membrane metalloendopeptidase) are a known cause of recessive Charcot-Marie-Tooth Neuropathy (CMT). A deep intronic variant, MME c.1188+428A>G (NM_000902.5), was identified through whole genome sequencing (WGS) of two Australian families with recessive inheritance of axonal CMT using the seqr platform. MME c.1188+428A>G was detected in a homozygous state in Family 1, and in a compound heterozygous state with a known pathogenic MME variant (c.467del; p.Pro156Leufs*14) in Family 2. AIMS We aimed to determine the pathogenicity of the MME c.1188+428A>G variant through segregation and splicing analysis. METHODS The splicing impact of the deep intronic MME variant c.1188+428A>G was assessed using an in vitro exon-trapping assay. RESULTS The exon-trapping assay demonstrated that the MME c.1188+428A>G variant created a novel splice donor site resulting in the inclusion of an 83 bp pseudoexon between MME exons 12 and 13. The incorporation of the pseudoexon into MME transcript is predicted to lead to a coding frameshift and premature termination codon (PTC) in MME exon 14 (p.Ala397ProfsTer47). This PTC is likely to result in nonsense mediated decay (NMD) of MME transcript leading to a pathogenic loss-of-function. INTERPRETATION To our knowledge, this is the first report of a pathogenic deep intronic MME variant causing CMT. This is of significance as deep intronic variants are missed using whole exome sequencing screening methods. Individuals with CMT should be reassessed for deep intronic variants, with splicing impacts being considered in relation to the potential pathogenicity of variants.
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Affiliation(s)
- Bianca R Grosz
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, New South Wales, Australia
- The University of Sydney, Camperdown, New South Wales, Australia
| | - Jevin M Parmar
- Rare Disease Genetics and Functional Genomics Research Group, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, Australia
- Centre for Medical Research, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Melina Ellis
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, New South Wales, Australia
- The University of Sydney, Camperdown, New South Wales, Australia
| | - Samantha Bryen
- Centre for Population Genomics, Garvan Institute of Medical Research, and UNSW Sydney, Sydney, New South Wales, Australia
- Centre for Population Genomics, Murdoch Children's Research Institute, Melbourne, Victoria, Australia
| | - Cas Simons
- Centre for Population Genomics, Garvan Institute of Medical Research, and UNSW Sydney, Sydney, New South Wales, Australia
- Centre for Population Genomics, Murdoch Children's Research Institute, Melbourne, Victoria, Australia
| | - Andre L M Reis
- Centre for Population Genomics, Garvan Institute of Medical Research, and UNSW Sydney, Sydney, New South Wales, Australia
- Genomics and Inherited Disease Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Igor Stevanovski
- Centre for Population Genomics, Garvan Institute of Medical Research, and UNSW Sydney, Sydney, New South Wales, Australia
- Genomics and Inherited Disease Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Ira W Deveson
- Centre for Population Genomics, Garvan Institute of Medical Research, and UNSW Sydney, Sydney, New South Wales, Australia
- Genomics and Inherited Disease Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Garth Nicholson
- The University of Sydney, Camperdown, New South Wales, Australia
- Molecular Medicine Laboratory and Neurology Department, Concord Repatriation General Hospital, Concord, New South Wales, Australia
| | - Nigel Laing
- Rare Disease Genetics and Functional Genomics Research Group, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, Australia
| | - Mathew Wallis
- Tasmanian Clinical Genetics Service, Tasmanian Health Service, Hobart, Australia
- School of Medicine and Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - Gianina Ravenscroft
- Rare Disease Genetics and Functional Genomics Research Group, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, Australia
| | - Kishore R Kumar
- The University of Sydney, Camperdown, New South Wales, Australia
- Molecular Medicine Laboratory and Neurology Department, Concord Repatriation General Hospital, Concord, New South Wales, Australia
- Translational Neurogenomics Group, Genomic and Inherited Disease Program, The Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
- St Vincent's Healthcare Campus, Faculty of Medicine, UNSW Sydney, Darlinghurst, New South Wales, Australia
| | - Steve Vucic
- The University of Sydney, Camperdown, New South Wales, Australia
- Brain and Nerve Research Centre, The University of Sydney, Sydney, New South Wales, Australia
| | - Marina L Kennerson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, New South Wales, Australia
- The University of Sydney, Camperdown, New South Wales, Australia
- Molecular Medicine Laboratory and Neurology Department, Concord Repatriation General Hospital, Concord, New South Wales, Australia
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Goleyjani Moghadam M, Elahi Z, Soveyzi M, Arzhangi S, Nafissi S, Najmabadi H, Kahrizi K, Fattahi Z. Expanding the Molecular Spectrum of HK1-Related Charcot-Marie-Tooth Disease, Type 4G; the First Report in Iran. ARCHIVES OF IRANIAN MEDICINE 2023; 26:279-284. [PMID: 38301092 PMCID: PMC10685863 DOI: 10.34172/aim.2023.43] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 03/05/2023] [Indexed: 02/03/2024]
Abstract
Charcot-Marie-Tooth disease type 4G (CMT4G) was first reported in Balkan Gypsies as a myelinopathy starting with progressive distal lower limb weakness, followed by upper limb involvement and prominent distal sensory impairment later in the patient's life. So far, CMT4G has been only reported in European Roma communities with two founder homozygous variants; g.9712G>C and g.11027G>A, located in the 5'-UTR of the HK1 gene. Here, we present the first Iranian CMT4G patient manifesting progressive distal lower limb weakness from 11 years of age and diagnosed with chronic demyelinating sensorimotor polyneuropathy. Whole-exome sequencing for this patient revealed a homozygous c.19C>T (p. Arg7*) variant in the HK1 gene. This report expands the mutational spectrum of the HK1-related CMT disorder and provides supporting evidence for the observation of CMT4G outside the Roma population. Interestingly, the same Arg7* variant is recently observed in another unrelated Pakistani CMT patient, proposing a possible prevalence of this variant in the Middle Eastern populations.
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Affiliation(s)
| | - Zohreh Elahi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
- Kariminejad - Najmabadi Pathology & Genetics Center, Tehran, Iran
| | - Mohamad Soveyzi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Sanaz Arzhangi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Shahriar Nafissi
- Iranian Neuromuscular Research Center (INMRC), Tehran University of Medical Sciences, Tehran, Iran
- Department of Neurology, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Hossein Najmabadi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
- Kariminejad - Najmabadi Pathology & Genetics Center, Tehran, Iran
| | - Kimia Kahrizi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Zohreh Fattahi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
- Kariminejad - Najmabadi Pathology & Genetics Center, Tehran, Iran
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Omidpanah N, Saadat M. Introducing a new index for selecting genetic polymorphisms for association studies. EXCLI JOURNAL 2022; 21:814-817. [PMID: 35949492 PMCID: PMC9360471 DOI: 10.17179/excli2022-5004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 06/09/2022] [Indexed: 11/07/2022]
Affiliation(s)
- Nafiseh Omidpanah
- Department of Biology, College of Sciences, Shiraz University, Shiraz, Iran
| | - Mostafa Saadat
- Department of Biology, College of Sciences, Shiraz University, Shiraz, Iran,*To whom correspondence should be addressed: Mostafa Saadat, Department of Biology, College of Science, Shiraz University, Shiraz 71467-13565, Iran, E-mail:
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