Abstract
Infantile hypotonia with psychomotor retardation and characteristic facies 1 (IHPRF1) is caused by biallelic mutations in the NALCN gene, the major ion channel responsible for the background Na + conduction in neurons. Through whole-exome sequencing (WES), we report three novel homozygous variants in three families, including c.1434 + 1G > A, c.3269G > A, and c.2648G > T, which are confirmed and segregated by Sanger sequencing. Consequently, intron 12’s highly conserved splice donor location is disrupted by the pathogenic c.1434 + 1G > A variation, most likely causing the protein to degrade through nonsense-mediated decay (NMD). Subsequently, a premature stop codon is thus generated at amino acid 1090 of the protein as a result of the pathogenic c.3269G > A; p.W1090* variation, resulting in NMD or truncated protein production. Lastly, the missense mutation c.2648G > T; p.G883V can play a critical role in the interplay of functional domains. This study introduces recurrent urinary tract infections for the first time, broadening the phenotypic range of IHPRF1 syndrome in addition to the genotypic spectrum. This trait may result from insufficient bladder emptying, which may be related to the NALCN channelosome’s function in background Na + conduction. This work advances knowledge about the molecular genetic underpinnings of IHPRF1 and introduces a novel phenotype through the widespread use of whole exome sequencing.
Graphical abstract
Similar content being viewed by others
Data availability
The data that support the findings of this study are available from the corresponding authors, upon request.
References
Cochet-Bissuel M, Lory P, Monteil A (2014) The sodium leak channel, NALCN, in health and disease. Front Cell Neurosci 8, https://doi.org/10.3389/fncel.2014.00132
Al-Sayed MD et al (2013) Mutations in NALCN cause an autosomal-recessive syndrome with severe hypotonia, speech impairment, and cognitive delay. Am J Human Gene 93:721–726. https://doi.org/10.1016/j.ajhg.2013.08.001
Chua H, Wulf M, Weidling C, Rasmussen L, Pless S (2020) The NALCN channel complex is voltage sensitive and directly modulated by extracellular calcium. Science Advances 6:eaaz3154
Xie J et al (2020). Structure of the human sodium leak channel NALCN in complex with FAM155A. Nat Commu 11, https://doi.org/10.1038/s41467-020-19667-z
Karimi AH, Karimi MR, Farnia P, Parvini F, Foroutan M (2020) <p>A homozygous truncating mutation in <em>NALCN</em> causing IHPRF1: detailed clinical manifestations and a review of literature</p>. Appl Clin Genet 13:151–157. https://doi.org/10.2147/tacg.S261781
Bouasse M, Impheng H, Servant Z, Lory P, Monteil A (2019) Functional expression of CLIFAHDD and IHPRF pathogenic variants of the NALCN channel in neuronal cells reveals both gain- and loss-of-function properties. Sci Rep 9, https://doi.org/10.1038/s41598-019-48071-x
Li H, Durbin R (2010) Fast and accurate long-read alignment with Burrows-Wheeler transform. Bioinformatics 26:589–595
Li H et al (2009) The sequence alignment/map format and SAMtools. Bioinformatics 25:2078–2079
McKenna A et al (2010) The genome analysis toolkit: a MapReduce framework for analyzing next-generation DNA sequencing data. Genome Res 20:1297–1303
Zhou L, Liu H, Zhao Q, Wu J, Yan Z (2022) Architecture of the human NALCN channelosome. Cell Discov 8:33. https://doi.org/10.1038/s41421-022-00392-4
Richards S et al (2015) Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Genet Med 17:405–424. https://doi.org/10.1038/gim.2015.30
Schwarz JM, Rodelsperger C, Schuelke M, Seelow D (2010) MutationTaster evaluates disease-causing potential of sequence alterations. Nat Methods 7:575–576. https://doi.org/10.1038/nmeth0810-575
Shihab HA et al (2015) An integrative approach to predicting the functional effects of non-coding and coding sequence variation. Bioinformatics 31:1536–1543. https://doi.org/10.1093/bioinformatics/btv009
Chun S, Fay JC (2009) Identification of deleterious mutations within three human genomes. Genome Res 19:1553–1561. https://doi.org/10.1101/gr.092619.109
Malhis N, Jacobson M, Jones SJM, Gsponer J (2020) LIST-S2: taxonomy based sorting of deleterious missense mutations across species. Nucleic Acids Res 48:W154–W161. https://doi.org/10.1093/nar/gkaa288
Karczewski KJ et al (2020) The mutational constraint spectrum quantified from variation in 141,456 humans. Nature 581:434–443. https://doi.org/10.1038/s41586-020-2308-7
Gal M et al (2016) A novel homozygous splice site mutation in NALCN identified in siblings with cachexia, strabismus, severe intellectual disability, epilepsy and abnormal respiratory rhythm. Eur J Med Genet 59:204–209. https://doi.org/10.1016/j.ejmg.2016.02.007
Zhang Z et al (2009) Noisy splicing, more than expression regulation, explains why some exons are subject to nonsense-mediated mRNA decay. BMC Biol 7:23. https://doi.org/10.1186/1741-7007-7-23
Kang Y, Chen L (2022) Structure and mechanism of NALCN-FAM155A-UNC79-UNC80 channel complex. Nat Commu 13, https://doi.org/10.1038/s41467-022-30403-7
Kschonsak M et al (2020) Structure of the human sodium leak channel NALCN. Nature 587:313–318. https://doi.org/10.1038/s41586-020-2570-8
Storme O, Tiran Saucedo J, Garcia-Mora A, Dehesa-Davila M, Naber KG (2019) Risk factors and predisposing conditions for urinary tract infection. Ther Adv Urol 11:1756287218814382. https://doi.org/10.1177/1756287218814382
Ferreira JJ et al (2021) SLO21/NALCN a sodium signaling complex that regulates uterine activity. iScience 24:103210. https://doi.org/10.1016/j.isci.2021.103210
Uhlen M et al (2015) Proteomics Tissue-based map of the human proteome. Science 347:1260419. https://doi.org/10.1126/science.1260419
Acknowledgements
Sincere gratitude to the families for their participation in this study.
Author information
Authors and Affiliations
Contributions
STF: conceptualization; data curation; investigation; visualization; formal analysis; methodology; software; validation; writing — review and editing; SB: conceptualization; data curation; investigation; visualization; roles/writing — original draft; HS: conceptualization; investigation; visualization; software; validation; writing — review and editing; SS: methodology; investigation; validation, writing—review and editing; FFB: validation; writing — review and editing. BS: investigation; validation; writing — review and editing. SJ: investigation; methodology; writing — review and editing. SHT: methodology; investigation; validation, writing — review and editing; RM: conceptualization; investigation; methodology; supervision; validation; writing — review and editing; MM: conceptualization; data curation; formal analysis; funding acquisition; investigation; methodology; project administration; resources; supervision; validation; writing — review and editing. MRG: conceptualization; data curation; formal analysis; investigation; project administration; resources; supervision; validation; writing — review and editing.
Corresponding authors
Ethics declarations
Ethical approval and consent to participate
This study was approved by the Research Ethics Committee of the Faculty of Medicine, Shahid Beheshti University of Medical Sciences, and was conducted in accordance with the tenets of the Declaration of Helsinki. Informed consent was obtained from parents.
Consent for publication
All the contributing authors agreed for the publication in this journal.
Conflict of interest
The authors declare no competing interests.
Additional information
Publisher's note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Tehrani Fateh, S., Bagheri, S., Sadeghi, H. et al. Extending and outlining the genotypic and phenotypic spectrum of novel mutations of NALCN gene in IHPRF1 syndrome: identifying recurrent urinary tract infection. Neurol Sci 44, 4491–4498 (2023). https://doi.org/10.1007/s10072-023-06960-0
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10072-023-06960-0