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Bamaga AK, Muthaffar OY, Alyazidi AS, Abu Alqam R. Giant Axonal Neuropathy: A Case Report of Subclinical Childhood Manifestations. Cureus 2024; 16:e54368. [PMID: 38500911 PMCID: PMC10948177 DOI: 10.7759/cureus.54368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/17/2024] [Indexed: 03/20/2024] Open
Abstract
Giant axonal neuropathy (GAN) is a rare, inherited neurodegenerative disease that affects both the central and peripheral nervous systems. It is mostly characterized by a progressive loss of motor and sensory function, which can begin in early childhood. GAN is thought to be caused by a mutation in the GAN gene on chromosome 16q24.1. We report a seven-year-old Saudi male child with GAN who was diagnosed using whole-exome sequencing. The child presented with a history of progressive weakness and muscle wasting in the arms and legs as well as difficulty walking. The sequencing identified a mutation in the GAN gene (NM_022041.3: c.1456G>A). Electrodiagnostic studies showed evidence of diffuse axonal motor and sensory polyneuropathy involving cranial nerves. This case report adds to the growing evidence that whole-exome sequencing can be a useful tool for diagnosing rare inherited neuromuscular disorders. It also highlights the importance of early diagnosis and intervention for this condition.
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Affiliation(s)
- Ahmed K Bamaga
- Pediatrics, King Abdulaziz University Hospital, Jeddah, SAU
| | - Osama Y Muthaffar
- Pediatrics, King Abdulaziz University Faculty of Medicine, Jeddah, SAU
| | - Anas S Alyazidi
- Medicine, King Abdulaziz University Faculty of Medicine, Jeddah, SAU
| | - Rakan Abu Alqam
- Medicine, King Abdulaziz University Faculty of Medicine, Jeddah, SAU
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Ashrafi MR, Dehnavi AZ, Tavasoli AR, Heidari M, Ghahvechi Akbari M, Ronagh AR, Ghafouri M, Mahdieh N, Mohammadi P, Rezaei Z. Expanding the genetic spectrum of giant axonal neuropathy: Two novel variants in Iranian families. Mol Genet Genomic Med 2023. [PMID: 36866531 DOI: 10.1002/mgg3.2159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023] Open
Abstract
BACKGROUND Giant axonal neuropathy (GAN) is a progressive childhood hereditary polyneuropathy that affects both the peripheral and central nervous systems. Disease-causing variants in the gigaxonin gene (GAN) cause autosomal recessive giant axonal neuropathy. Facial weakness, nystagmus, scoliosis, kinky or curly hair, pyramidal and cerebellar signs, and sensory and motor axonal neuropathy are the main symptoms of this disorder. Here, we report two novel variants in the GAN gene from two unrelated Iranian families. METHODS Clinical and imaging data of patients were recorded and evaluated, retrospectively. Whole-exome sequencing (WES) was undertaken in order to detect disease-causing variants in participants. Confirmation of a causative variant in all three patients and their parents was carried out using Sanger sequencing and segregation analysis. In addition, for comparing to our cases, we reviewed all relevant clinical data of previously published cases of GAN between the years 2013-2020. RESULTS Three patients from two unrelated families were included. Using WES, we identified a novel nonsense variant [NM_022041.3:c.1162del (p.Leu388Ter)], in a 7-year-old boy of family 1, and a likely pathogenic missense variant [NM_022041.3:c.370T>A (p.Phe124Ile)], in two affected siblings of the family 2. Clinical examination revealed typical features of GAN-1 in all three patients, including walking difficulties, ataxic gait, kinky hair, sensory-motor polyneuropathy, and nonspecific neuroimaging abnormalities. Review of 63 previously reported cases of GAN indicated unique kinky hair, gait problem, hyporeflexia/areflexia, and sensory impairment were the most commonly reported clinical features. CONCLUSIONS One homozygous nonsense variant and one homozygous missense variant in the GAN gene were discovered for the first time in two unrelated Iranian families that expand the mutation spectrum of GAN. Imaging findings are nonspecific, but the electrophysiological study in addition to history is helpful to achieve the diagnosis. The molecular test confirms the diagnosis.
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Affiliation(s)
- Mahmoud Reza Ashrafi
- Ataxia Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran.,Department of Paediatrics, Division of Paediatric Neurology, Growth and Development Research Center, Children's Medical Centre, Paediatrics Centre of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Zare Dehnavi
- Ataxia Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Reza Tavasoli
- Ataxia Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran.,Myelin Disorders Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran.,Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Morteza Heidari
- Ataxia Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran.,Myelin Disorders Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoud Ghahvechi Akbari
- Ataxia Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran.,Physical Medicine and Rehabilitation department, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Reza Ronagh
- Pediatric Neurology Department, Alborz University of Medical Sciences, Karaj, Iran
| | - Mohammad Ghafouri
- Ataxia Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Nejat Mahdieh
- Genetic Research Center, Rajaei Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Pouria Mohammadi
- Ataxia Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran.,Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Zahra Rezaei
- Ataxia Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
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Shirakaki S, Roshmi RR, Yokota T. Genetic Approaches for the Treatment of Giant Axonal Neuropathy. J Pers Med 2022; 13:jpm13010091. [PMID: 36675752 PMCID: PMC9865904 DOI: 10.3390/jpm13010091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/18/2022] [Accepted: 12/23/2022] [Indexed: 01/01/2023] Open
Abstract
Giant axonal neuropathy (GAN) is a pediatric, hereditary, neurodegenerative disorder that affects both the central and peripheral nervous systems. It is caused by mutations in the GAN gene, which codes for the gigaxonin protein. Gigaxonin plays a role in intermediate filament (IF) turnover hence loss of function of this protein leads to IF aggregates in various types of cells. These aggregates can lead to abnormal cellular function that manifests as a diverse set of symptoms in persons with GAN including nerve degeneration, cognitive issues, skin diseases, vision loss, and muscle weakness. GAN has no cure at this time. Currently, an adeno-associated virus (AAV) 9-mediated gene replacement therapy is being tested in a phase I clinical trial for the treatment of GAN. This review paper aims to provide an overview of giant axonal neuropathy and the current efforts at developing a treatment for this devastating disease.
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Mir YR, Zeng X, Taneja AK, Hassan A, Sheth J, Kuchay RAH. Giant axonal neuropathy with novel GAN pathogenic variant in a patient of consanguineous origin from Poonch Jammu and Kashmir-India. Mol Biol Rep 2021; 48:1607-1614. [PMID: 33528728 DOI: 10.1007/s11033-021-06166-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 01/15/2021] [Indexed: 10/22/2022]
Abstract
Giant axonal neuropathy (GAN) is a severe and rare autosomal recessive neurodegenerative disorder of childhood affecting both the peripheral and central nervous systems (CNS). It is caused by mutations in the GAN (gigaxonin) gene linked to chromosome 16q24. Here, we present a 15-year-old male patient with GAN from a consanguineous family of Poonch, Jammu and Kashmir (J&K)-India. Whole-exome sequencing (WES) was employed to unravel the genetic cause of GAN in the proband. Pathogenic variant identified with WES was confirmed in other affected sibling using Sanger sequencing. Magnetic resonance imaging (MRI) and detailed clinical investigation was also carried out on proband. WES revealed a novel homozygous stopgain GAN mutation (NM_022041, c.C1028G, p.S343X) in the patient. MRI of brain displayed bilateral symmetrical confluent areas of deep white matter signal changes affecting periventricular regions (with sparing of subcortical U-fibers), posterior limbs of internal capsules, thalami, external capsules, and semioval centers. The patient was initially suspected to be a case of metachromatic leukodystrophy. However, WES analysis revealed a pathogenic variant in GAN gene as causative. No other pathogenic variant relevant to any other type of dystrophy was reported in WES. Our findings extend the geographical distribution of GAN to even a very remote region in India, extend the mutational and imaging spectrum of GAN and substantiate the need for introducing genetic testing and counselling in primary referral centers/district hospitals in India.
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Affiliation(s)
- Yaser Rafiq Mir
- Department of Biotechnology, Baba Ghulam Shah Badshah University, Rajouri, J&K, 185234, India
| | - Xue Zeng
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA
| | - Atul K Taneja
- Imaging Department, Hospital Israelita Albert Einstein, São Paulo, SP, Brazil.,Department of Radiology, Hospital do Coração (HCor) and Teleimagem, São Paulo, SP, Brazil
| | - Asima Hassan
- Department of Health and Medical Education, Srinagar, J&K, India
| | - Jayesh Sheth
- Foundation for Research in Genetics and Endocrinology, Institute of Human Genetics, Ahmedabad, Gujarat, India
| | - Raja A H Kuchay
- Department of Biotechnology, Baba Ghulam Shah Badshah University, Rajouri, J&K, 185234, India.
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