Biallelic mutations in neurofascin cause neurodevelopmental impairment and peripheral demyelination

Stephanie Efthymiou, Vincenzo Salpietro, Nancy Malintan, Mallory Poncelet, Yamna Kriouile, Sara Fortuna, Rita De Zorzi, Katelyn Payne, Lindsay B. Henderson, Andrea Cortese, Sateesh Maddirevula, Nadia Alhashmi, Sarah Wiethoff, Mina Ryten, Juan A. Botia, Vincenzo Provitera, Markus Schuelke, Jana Vandrovcova, Laurence Walsh, Erin TortiValeria Iodice, Maryam Najafi, Ehsan Ghayoor Karimiani, Reza Maroofian, Karine Siquier-Pernet, Nathalie Boddaert, Pascale De Lonlay, Vincent Cantagrel, Mhammed Aguennouz, Mohamed El Khorassani, Miriam Schmidts, Fowzan S. Alkuraya, Simon Edvardson, Maria Nolano, Jérôme Devaux, Henry Houlden, Stanislav Groppa, Blagovesta Marinova Karashova, Wolfgang Nachbauer, Sylvia Boesch, Larissa Arning, Dagmar Timmann, Bru Cormand, Belen Pérez-Dueñas, Jatinder S. Goraya, Tipu Sultan, Jun Mine, Daniela Avdjieva, Hadil Kathom, Radka Tincheva, Selina Banu, Mercedes Pineda-Marfa, Pierangelo Veggiotti, Michel D. Ferrari, Arn M.J.M. Van Den Maagdenberg, Alberto Verrotti, Giangluigi Marseglia, Salvatore Savasta, Mayte García-Silva, Alfons Macaya Ruiz, Barbara Garavaglia, Eugenia Borgione, Simona Portaro, Benigno Monteagudo Sanchez, Richard Boles, Savvas Papacostas, Michail Vikelis, James Rothman, Dimitri Kullmann, Eleni Zamba Papanicolaou, Efthymios Dardiotis, Shazia Maqbool, Shahnaz Ibrahim, Salman Kirmani, Nuzhat Noureen Rana, Osama Atawneh, Shen Yang Lim, Farooq Shaikh, George Koutsis, Marianthi Breza, Salvatore Mangano, Carmela Scuderi, Eugenia Borgione, Giovanna Morello, Tanya Stojkovic, Massimo Zollo, Gali Heimer, Yves A. Dauvilliers, Carlo Minetti, Issam Al-Khawaja, Fuad Al-Mutairi, Sherifa Hamed, Menelaos Pipis, Conceicao Bettencourt, Simon Rinaldi

Research output: Contribution to journalArticlepeer-review

52 Citations (Scopus)

Abstract

Axon pathfinding and synapse formation are essential processes for nervous system development and function. The assembly of myelinated fibres and nodes of Ranvier is mediated by a number of cell adhesion molecules of the immunoglobulin superfamily including neurofascin, encoded by the NFASC gene, and its alternative isoforms Nfasc186 and Nfasc140 (located in the axonal membrane at the node of Ranvier) and Nfasc155 (a glial component of the paranodal axoglial junction). We identified 10 individuals from six unrelated families, exhibiting a neurodevelopmental disorder characterized with a spectrum of central (intellectual disability, developmental delay, motor impairment, speech difficulties) and peripheral (early onset demyelinating neuropathy) neurological involvement, who were found by exome or genome sequencing to carry one frameshift and four different homozygous non-synonymous variants in NFASC. Expression studies using immunostaining-based techniques identified absent expression of the Nfasc155 isoform as a consequence of the frameshift variant and a significant reduction of expression was also observed in association with two non-synonymous variants affecting the fibronectin type III domain. Cell aggregation studies revealed a severely impaired Nfasc155-CNTN1/CASPR1 complex interaction as a result of the identified variants. Immunofluorescence staining of myelinated fibres from two affected individuals showed a severe loss of myelinated fibres and abnormalities in the paranodal junction morphology. Our results establish that recessive variants affecting the Nfasc155 isoform can affect the formation of paranodal axoglial junctions at the nodes of Ranvier. The genetic disease caused by biallelic NFASC variants includes neurodevelopmental impairment and a spectrum of central and peripheral demyelination as part of its core clinical phenotype. Our findings support possible overlapping molecular mechanisms of paranodal damage at peripheral nerves in both the immune-mediated and the genetic disease, but the observation of prominent central neurological involvement in NFASC biallelic variant carriers highlights the importance of this gene in human brain development and function.

Original languageEnglish
Pages (from-to)2948-2964
Number of pages17
JournalBrain
Volume142
Issue number10
DOIs
Publication statusPublished - 1 Oct 2019

Keywords

  • Neurodevelopment
  • Neurofascin
  • Peripheral demyelination

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