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Diarra S, Ghosh S, Cissé L, Coulibaly T, Yalcouyé A, Harmison G, Diallo S, Diallo SH, Coulibaly O, Schindler A, Cissé CAK, Maiga AB, Bamba S, Samassekou O, Khokha MK, Mis EK, Lakhani SA, Donovan FX, Jacobson S, Blackstone C, Guinto CO, Landouré G, Bonifacino JS, Fischbeck KH, Grunseich C. AP2A2 mutation and defective endocytosis in a Malian family with hereditary spastic paraplegia. Neurobiol Dis 2024; 198:106537. [PMID: 38772452 PMCID: PMC11209852 DOI: 10.1016/j.nbd.2024.106537] [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: 01/13/2024] [Revised: 04/17/2024] [Accepted: 05/17/2024] [Indexed: 05/23/2024] Open
Abstract
Hereditary spastic paraplegia (HSP) comprises a large group of neurogenetic disorders characterized by progressive lower extremity spasticity. Neurological evaluation and genetic testing were completed in a Malian family with early-onset HSP. Three children with unaffected consanguineous parents presented with symptoms consistent with childhood-onset complicated HSP. Neurological evaluation found lower limb weakness, spasticity, dysarthria, seizures, and intellectual disability. Brain MRI showed corpus callosum thinning with cortical and spinal cord atrophy, and an EEG detected slow background in the index patient. Whole exome sequencing identified a homozygous missense variant in the adaptor protein (AP) complex 2 alpha-2 subunit (AP2A2) gene. Western blot analysis showed reduced levels of AP2A2 in patient-iPSC derived neuronal cells. Endocytosis of transferrin receptor (TfR) was decreased in patient-derived neurons. In addition, we observed increased axon initial segment length in patient-derived neurons. Xenopus tropicalis tadpoles with ap2a2 knockout showed cerebral edema and progressive seizures. Immunoprecipitation of the mutant human AP-2-appendage alpha-C construct showed defective binding to accessory proteins. We report AP2A2 as a novel genetic entity associated with HSP and provide functional data in patient-derived neuron cells and a frog model. These findings expand our understanding of the mechanism of HSP and improve the genetic diagnosis of this condition.
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Affiliation(s)
- Salimata Diarra
- Université des Sciences, des Techniques, et des Technologies de Bamako (USTTB), Bamako, Mali; Neurogenetics Branch, NINDS, NIH, Bethesda, MD, United States; Yale University, Pediatric Genomics Discovery Program, Department of Pediatrics, New Haven, CT, United States
| | - Saikat Ghosh
- Neurosciences and Cellular and Structural Biology Division, NICHD, NIH, Bethesda, MD, United States
| | - Lassana Cissé
- Service de Neurologie, CHU du Point "G", Bamako, Mali
| | - Thomas Coulibaly
- Université des Sciences, des Techniques, et des Technologies de Bamako (USTTB), Bamako, Mali; Neurosciences and Cellular and Structural Biology Division, NICHD, NIH, Bethesda, MD, United States
| | - Abdoulaye Yalcouyé
- Université des Sciences, des Techniques, et des Technologies de Bamako (USTTB), Bamako, Mali; Division of Human Genetics, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - George Harmison
- Neurogenetics Branch, NINDS, NIH, Bethesda, MD, United States
| | | | | | - Oumar Coulibaly
- Service de Chirurgie Pédiatrique, CHU du Gabriel Touré, Bamako, Mali
| | - Alice Schindler
- Neurogenetics Branch, NINDS, NIH, Bethesda, MD, United States
| | - Cheick A K Cissé
- Université des Sciences, des Techniques, et des Technologies de Bamako (USTTB), Bamako, Mali
| | - Alassane B Maiga
- Université des Sciences, des Techniques, et des Technologies de Bamako (USTTB), Bamako, Mali; Service de Neurologie, CHU du Point "G", Bamako, Mali
| | - Salia Bamba
- Université des Sciences, des Techniques, et des Technologies de Bamako (USTTB), Bamako, Mali
| | - Oumar Samassekou
- Université des Sciences, des Techniques, et des Technologies de Bamako (USTTB), Bamako, Mali
| | - Mustafa K Khokha
- Yale University, Pediatric Genomics Discovery Program, Department of Pediatrics, New Haven, CT, United States
| | - Emily K Mis
- Yale University, Pediatric Genomics Discovery Program, Department of Pediatrics, New Haven, CT, United States
| | - Saquib A Lakhani
- Yale University, Pediatric Genomics Discovery Program, Department of Pediatrics, New Haven, CT, United States
| | - Frank X Donovan
- Cancer Genetics and Comparative Genomics Branch, NHGRI, NIH, Bethesda, MD, United States
| | - Steve Jacobson
- Neuroimmunology Division, NINDS, NIH, Bethesda, MD, United States
| | - Craig Blackstone
- Movement Disorders Division, Department of Neurology, Harvard Medicine School, Massachusetts General Hospital, Boston, MA, United States
| | - Cheick O Guinto
- Université des Sciences, des Techniques, et des Technologies de Bamako (USTTB), Bamako, Mali; Service de Neurologie, CHU du Point "G", Bamako, Mali
| | - Guida Landouré
- Université des Sciences, des Techniques, et des Technologies de Bamako (USTTB), Bamako, Mali; Neurogenetics Branch, NINDS, NIH, Bethesda, MD, United States; Service de Neurologie, CHU du Point "G", Bamako, Mali
| | - Juan S Bonifacino
- Neurosciences and Cellular and Structural Biology Division, NICHD, NIH, Bethesda, MD, United States
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Mulkerrin G, França MC, Lope J, Tan EL, Bede P. Neuroimaging in hereditary spastic paraplegias: from qualitative cues to precision biomarkers. Expert Rev Mol Diagn 2022; 22:745-760. [PMID: 36042576 DOI: 10.1080/14737159.2022.2118048] [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: 01/18/2023]
Abstract
INTRODUCTION : Hereditary spastic paraplegias (HSP) include a clinically and genetically heterogeneous group of conditions. Novel imaging modalities have been increasingly applied to HSP cohorts which helps to quantitatively evaluate the integrity of specific anatomical structures and develop monitoring markers for both clinical care and future clinical trials. AREAS COVERED : Advances in HSP imaging are systematically reviewed with a focus on cohort sizes, imaging modalities, study design, clinical correlates, methodological approaches, and key findings. EXPERT OPINION : A wide range of imaging techniques have been recently applied to HSP cohorts. Common shortcomings of existing studies include the evaluation of genetically unconfirmed or admixed cohorts, limited sample sizes, unimodal imaging approaches, lack of postmortem validation, and a limited clinical battery, often exclusively focusing on motor aspects of the condition. A number of innovative methodological approaches have also be identified, such as robust longitudinal study designs, the implementation of multimodal imaging protocols, complementary cognitive assessments, and the comparison of HSP cohorts to MND cohorts. Collaborative multicentre initiatives may overcome sample limitations, and comprehensive clinical profiling with motor, extrapyramidal, cerebellar, and neuropsychological assessments would permit systematic clinico-radiological correlations. Academic achievements in HSP imaging have the potential to be developed into viable clinical applications to expedite the diagnosis and monitor disease progression.
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Affiliation(s)
| | - Marcondes C França
- Department of Neurology, The State University of Campinas, São Paulo, Brazil
| | - Jasmin Lope
- Computational Neuroimaging Group, Trinity College Dublin, Ireland
| | - Ee Ling Tan
- Computational Neuroimaging Group, Trinity College Dublin, Ireland
| | - Peter Bede
- Department of Neurology, St James's Hospital, Dublin, Ireland.,Computational Neuroimaging Group, Trinity College Dublin, Ireland
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Sager G, Turkyilmaz A, Ates EA, Kutlubay B. HACE1, GLRX5, and ELP2 gene variant cause spastic paraplegies. Acta Neurol Belg 2022; 122:391-399. [PMID: 33813722 DOI: 10.1007/s13760-021-01649-7] [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: 12/11/2020] [Accepted: 03/08/2021] [Indexed: 10/21/2022]
Abstract
Hereditary spastic paraplegias (HSPs) are a clinically and genetically heterogeneous group of conditions that are characterized by lower limb spasticity and weakness. Considering the clinical overlap between metabolic causes, genetic diseases, and autosomal recessive HSP, differentiation between these types can be difficult based solely on their clinical characteristics. This study aimed to investigate the genetic etiology of patients with clinically suspected HSP. The study group was composed of seven Turkish families who each had two affected children and three families who each had a single affected child (17 total patients). The 17 probands (14 males, 3 females) underwent whole exome sequencing. Five typical HSP genes (FA2H, AP4M1, AP4E1, CYP7B1, and MAG) and three genes not previously related to HSP (HACE1, GLRX5, ad ELP2) were identified in 14 probands. Eight novel variants were identified in seven families: c.653 T > C (p.Leu218Pro) in the FA2H gene, c.347G > A (p.Gly116Asp) in the GLRX5 gene, c.2581G > C (p.Ala861Pro) in the HACE1 gene, c.1580G > A (p.Arg527Gln) and c.1189-1G > A in the ELP2 gene, c.10C > T (p.Gln4*) and c.1025 + 1G > A in the AP4M1 gene, c.1291delG (p.Gly431Alafs*3) and c.3250delA (p.Ile1084*) in the AP4E1 gene, and c.475 T > G (p.Cys159Gly) in the MAG gene. The growing use of next-generation sequencing improved diagnosis but also led to the continual identification of new causal genes for neurogenetic diseases associated with lower limb spasticity. The increasing number of HSP genes identified thus far highlights the extreme genetic heterogeneity of these disorders and their clinical and functional overlap with other neurological conditions. Our findings suggest that the HACE1, GLRX5, and ELP2 genes are genetic causes of HSP.
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Affiliation(s)
- Gunes Sager
- Department of Pediatric Neurology, Kartal Dr. Lutfi Kirdar City Hospital, Semsi Denizer Avenue, Cevizli, 34890, Kartal, Istanbul, Turkey.
| | - Ayberk Turkyilmaz
- Department of Medical Genetics, Erzurum City Hospital, Erzurum, Turkey
| | - Esra Arslan Ates
- Department of Medical Genetics, Marmara University Pendik Training and Research Hospital, Istanbul, Turkey
| | - Busra Kutlubay
- Department of Pediatric Neurology, Umraniye Training and Research Hospital, Istanbul, Turkey
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Mahungu AC, Monnakgotla N, Nel M, Heckmann JM. A review of the genetic spectrum of hereditary spastic paraplegias, inherited neuropathies and spinal muscular atrophies in Africans. Orphanet J Rare Dis 2022; 17:133. [PMID: 35331287 PMCID: PMC8944057 DOI: 10.1186/s13023-022-02280-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 03/07/2022] [Indexed: 11/10/2022] Open
Abstract
Background Genetic investigations of inherited neuromuscular disorders in Africans, have been neglected. We aimed to summarise the published data and comment on the genetic evidence related to inherited neuropathies (Charcot-Marie-Tooth disease (CMT)), hereditary spastic paraplegias (HSP) and spinal muscular atrophy (SMA) in Africans. Methods PubMed was searched for relevant articles and manual checking of references and review publications were performed for African-ancestry participants with relevant phenotypes and identified genetic variants. For each case report we extracted phenotype information, inheritance pattern, variant segregation and variant frequency in population controls (including up to date frequencies from the gnomAD database). Results For HSP, 23 reports were found spanning the years 2000–2019 of which 19 related to North Africans, with high consanguinity, and six included sub-Saharan Africans. For CMT, 19 reports spanning years 2002–2021, of which 16 related to North Africans and 3 to sub-Saharan Africans. Most genetic variants had not been previously reported. There were 12 reports spanning years 1999–2020 related to SMN1-SMA caused by homozygous exon 7 ± 8 deletion. Interestingly, the population frequency of heterozygous SMN1-exon 7 deletion mutations appeared 2 × lower in Africans compared to Europeans, in addition to differences in the architecture of the SMN2 locus which may impact SMN1-SMA prognosis. Conclusions Overall, genetic data on inherited neuromuscular diseases in sub-Saharan Africa, are sparse. If African patients with rare neuromuscular diseases are to benefit from the expansion in genomics capabilities and therapeutic advancements, then it is critical to document the mutational spectrum of inherited neuromuscular disease in Africa. Highlights Review of genetic variants reported in hereditary spastic paraplegia in Africans Review of genetic variants reported in genetic neuropathies in Africans Review of genetic underpinnings of spinal muscular atrophies in Africans Assessment of pathogenic evidence for candidate variants
Supplementary Information The online version contains supplementary material available at 10.1186/s13023-022-02280-2.
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Affiliation(s)
- Amokelani C Mahungu
- Neurology Research Group, University of Cape Town Neuroscience Institute, Cape Town, South Africa
| | | | - Melissa Nel
- Neurology Research Group, University of Cape Town Neuroscience Institute, Cape Town, South Africa
| | - Jeannine M Heckmann
- E8-74 Neurology, Department of Medicine, Groote Schuur Hospital and the University of Cape Town Neuroscience Institute, University of Cape Town, Cape Town, South Africa.
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