Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

NANS-mediated synthesis of sialic acid is required for brain and skeletal development

A Corrigendum to this article was published on 26 May 2017

This article has been updated


We identified biallelic mutations in NANS, the gene encoding the synthase for N-acetylneuraminic acid (NeuNAc; sialic acid), in nine individuals with infantile-onset severe developmental delay and skeletal dysplasia. Patient body fluids showed an elevation in N-acetyl-D-mannosamine levels, and patient-derived fibroblasts had reduced NANS activity and were unable to incorporate sialic acid precursors into sialylated glycoproteins. Knockdown of nansa in zebrafish embryos resulted in abnormal skeletal development, and exogenously added sialic acid partially rescued the skeletal phenotype. Thus, NANS-mediated synthesis of sialic acid is required for early brain development and skeletal growth. Normal sialylation of plasma proteins was observed in spite of NANS deficiency. Exploration of endogenous synthesis, nutritional absorption, and rescue pathways for sialic acid in different tissues and developmental phases is warranted to design therapeutic strategies to counteract NANS deficiency and to shed light on sialic acid metabolism and its implications for human nutrition.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Morphological and skeletal features of NANS-deficient patients.
Figure 2: Three-dimensional model of the NANS protein and mapping of amino acid residues affected by mutations.
Figure 3: Evidence of impaired NANS activity ex vivo and in cell culture.
Figure 4: Simplified scheme of N-acetylneuraminic acid metabolism in human.
Figure 5: Abnormal skeletal development in zebrafish with morpholino-mediated knockdown of nansa is partially rescued by exogenous sialic acid.

Similar content being viewed by others

Accession codes


NCBI Reference Sequence

Change history

  • 06 March 2017

    In the version of this article initially published, the name of author Torben Heise was given incorrectly as Thorben Heisse, and the name of author Valérie Cormier-Daire was given incorrectly as Valerie Cormier. The institutional affiliation for Delphine Heron was listed incorrectly as Institut IMAGINE, Hôpital Necker–Enfants Malades, Paris, France, and should have been listed as Département de Génétique Médicale et Centre de Référence Déficiences Intellectuelles, Groupe Hospitalier Pitié-Salpêtrière, Université Pierre et Marie Curie, Paris, France. The errors have been corrected in the HTML and PDF versions of the article.


  1. Salvador-Carulla, L. et al. Intellectual developmental disorders: towards a new name, definition and framework for “mental retardation/intellectual disability” in ICD-11. World Psychiatry 10, 175–180 (2011).

    Article  Google Scholar 

  2. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders 5th edn (American Psychiatric Publishing, 2013).

  3. de Ligt, J. et al. Diagnostic exome sequencing in persons with severe intellectual disability. N. Engl. J. Med. 367, 1921–1929 (2012).

    Article  CAS  Google Scholar 

  4. Gilissen, C. et al. Genome sequencing identifies major causes of severe intellectual disability. Nature 511, 344–347 (2014).

    Article  CAS  Google Scholar 

  5. van Karnebeek, C.D.M. & Stockler, S. Treatable inborn errors of metabolism causing intellectual disability: a systematic literature review. Mol. Genet. Metab. 105, 368–381 (2012).

    Article  CAS  Google Scholar 

  6. Bonafé, L. et al. Nosology and classification of genetic skeletal disorders: 2015 revision. Am. J. Med. Genet. 167, 2869–2892 (2015).

    Article  Google Scholar 

  7. Superti-Furga, A., Bonafé, L. & Rimoin, D.L. Molecular-pathogenetic classification of genetic disorders of the skeleton. Am. J. Med. Genet. 106, 282–293 (2001).

    Article  CAS  Google Scholar 

  8. Camera, G., Camera, A., Di Rocco, M. & Gatti, R. Sponastrime dysplasia: report on two siblings with metal retardation. Pediatr. Radiol. 23, 611–614 (1993).

    Article  CAS  Google Scholar 

  9. Geneviève, D. et al. Exclusion of the dymeclin and PAPSS2 genes in a novel form of spondyloepimetaphyseal dysplasia and mental retardation. Eur. J. Hum. Genet. 13, 541–546 (2005).

    Article  Google Scholar 

  10. Tarailo-Graovac, M. et al. Exome sequencing and the management of neurometabolic disorders. N. Engl. J. Med. (in the press).

  11. Cotton, T.R., Joseph, D.D., Jiao, W. & Parker, E.J. Probing the determinants of phosphorylated sugar-substrate binding for human sialic acid synthase. Biochim. Biophys. Acta 1844, 2257–2264 (2014).

    Article  CAS  Google Scholar 

  12. Galuska, S.P. et al. Quantification of nucleotide-activated sialic acids by a combination of reduction and fluorescent labeling. Anal. Chem. 82, 4591–4598 (2010).

    Article  CAS  Google Scholar 

  13. Büll, C. et al. Sialic acid glycoengineering using an unnatural sialic acid for the detection of sialoglycan biosynthesis defects and on-cell synthesis of siglec ligands. ACS Chem. Biol. 10, 2353–2363 (2015).

    Article  Google Scholar 

  14. Riemersma, M. et al. Disease mutations in CMP–sialic acid transporter SLC35A1 result in abnormal α-dystroglycan O-mannosylation, independent from sialic acid. Hum. Mol. Genet. 24, 2241–2246 (2015).

    Article  CAS  Google Scholar 

  15. Link, V., Shevchenko, A. & Heisenberg, C.P. Proteomics of early zebrafish embryos. BMC Dev. Biol. 6, 1 (2006).

    Article  Google Scholar 

  16. Eisen, J.S. & Smith, J.C. Controlling morpholino experiments: don't stop making antisense. Development 135, 1735–1743 (2008).

    Article  CAS  Google Scholar 

  17. Javidan, Y. & Schilling, T.F. Development of cartilage and bone. Methods Cell Biol. 76, 415–436 (2004).

    Article  Google Scholar 

  18. Wang, B. & Brand-Miller, J. The role and potential of sialic acid in human nutrition. Eur. J. Clin. Nutr. 57, 1351–1369 (2003).

    Article  CAS  Google Scholar 

  19. Simpson, M.A. et al. Infantile-onset symptomatic epilepsy syndrome caused by a homozygous loss-of-function mutation of GM3 synthase. Nat. Genet. 36, 1225–1229 (2004).

    Article  CAS  Google Scholar 

  20. Hu, H. et al. ST3GAL3 mutations impair the development of higher cognitive functions. Am. J. Hum. Genet. 89, 407–414 (2011).

    Article  CAS  Google Scholar 

  21. Fragaki, K. et al. Refractory epilepsy and mitochondrial dysfunction due to GM3 synthase deficiency. Eur. J. Hum. Genet. 21, 528–534 (2013).

    Article  CAS  Google Scholar 

  22. Boccuto, L. et al. A mutation in a ganglioside biosynthetic enzyme, ST3GAL5, results in salt & pepper syndrome, a neurocutaneous disorder with altered glycolipid and glycoprotein glycosylation. Hum. Mol. Genet. 23, 418–433 (2014).

    Article  CAS  Google Scholar 

  23. Mohamed, M. et al. Intellectual disability and bleeding diathesis due to deficient CMP–sialic acid transport. Neurology 81, 681–687 (2013).

    Article  CAS  Google Scholar 

  24. Roughley, P.J., White, R.J. & Santer, V. Comparison of proteoglycans extracted from high and low weight–bearing human articular cartilage, with particular reference to sialic acid content. J. Biol. Chem. 256, 12699–12704 (1981).

    CAS  PubMed  Google Scholar 

  25. Vincent, K. & Durrant, M.C. A structural and functional model for human bone sialoprotein. J. Mol. Graph. Model. 39, 108–117 (2013).

    Article  CAS  Google Scholar 

  26. Sodek, J., Ganss, B. & McKee, M.D. Osteopontin. Crit. Rev. Oral Biol. Med. 11, 279–303 (2000).

    Article  CAS  Google Scholar 

  27. Wang, B. Sialic acid is an essential nutrient for brain development and cognition. Annu. Rev. Nutr. 29, 177–222 (2009).

    Article  Google Scholar 

  28. Wang, B. Molecular mechanism underlying sialic acid as an essential nutrient for brain development and cognition. Adv. Nutr. 3, 465S–472S (2012).

    Article  CAS  Google Scholar 

  29. Sprenger, N. & Duncan, P.I. Sialic acid utilization. Adv. Nutr. 3, 392S–397S (2012).

    Article  CAS  Google Scholar 

  30. Salama, I. et al. No overall hyposialylation in hereditary inclusion body myopathy myoblasts carrying the homozygous M712T GNE mutation. Biochem. Biophys. Res. Commun. 328, 221–226 (2005).

    Article  CAS  Google Scholar 

  31. Malicdan, M.C., Noguchi, S., Hayashi, Y.K., Nonaka, I. & Nishino, I. Prophylactic treatment with sialic acid metabolites precludes the development of the myopathic phenotype in the DMRV-hIBM mouse model. Nat. Med. 15, 690–695 (2009).

    Article  CAS  Google Scholar 

  32. Oetke, C. et al. Evidence for efficient uptake and incorporation of sialic acid by eukaryotic cells. Eur. J. Biochem 268, 4553–4561 (2001).

    Article  CAS  Google Scholar 

  33. Nöhle, U. & Schauer, R. Uptake, metabolism and excretion of orally and intravenously administered, 14C- and 3H-labeled N-acetylneuraminic acid mixture in the mouse and rat. Hoppe-Seyler's Z. Physiol. Chem. 362, 1495–1506 (1981).

    Article  Google Scholar 

  34. Tangvoranuntakul, P. et al. Human uptake and incorporation of an immunogenic nonhuman dietary sialic acid. Proc. Natl. Acad. Sci. USA 100, 12045–12050 (2003).

    Article  CAS  Google Scholar 

  35. Samraj, A.N. et al. A red meat–derived glycan promotes inflammation and cancer progression. Proc. Natl. Acad. Sci. USA 112, 542–547 (2015).

    Article  CAS  Google Scholar 

  36. Bode, L. Human milk oligosaccharides: every baby needs a sugar mama. Glycobiology 22, 1147–1162 (2012).

    Article  CAS  Google Scholar 

  37. Fuhrer, A. et al. Milk sialyllactose influences colitis in mice through selective intestinal bacterial colonization. J. Exp. Med. 207, 2843–2854 (2010).

    Article  CAS  Google Scholar 

  38. Röhrig, C.H., Choi, S.S. & Baldwin, N. The nutritional role of free sialic acid, a human milk monosaccharide, and its application as a functional food ingredient. Crit. Rev. Food Sci. Nutr. (doi:10.1080/10408398.2015.1040113 (2016)).

  39. Van der Auwera, G.A. et al. From FastQ data to high confidence variant calls: the Genome Analysis Toolkit best practices pipeline. Curr. Protoc. Bioinformatics 43, 1–33 (2013).

    Google Scholar 

  40. Wang, K., Li, M. & Hakonarson, H. ANNOVAR: functional annotation of genetic variants from high-throughput sequencing data. Nucleic Acids Res. 38, e164 (2010).

    Article  Google Scholar 

  41. Yang, J. et al. The I-TASSER Suite: protein structure and function prediction. Nat. Methods 12, 7–8 (2015).

    Article  CAS  Google Scholar 

  42. Gunawan, J. et al. Structural and mechanistic analysis of sialic acid synthase NeuB from Neisseria meningitidis in complex with Mn2+, phosphoenolpyruvate, and N-acetylmannosaminitol. J. Biol. Chem. 280, 3555–3563 (2005).

    Article  CAS  Google Scholar 

  43. Hamada, T. et al. Solution structure of the antifreeze-like domain of human sialic acid synthase. Protein Sci. 15, 1010–1016 (2006).

    Article  CAS  Google Scholar 

  44. Rajavel, K.S. & Neufeld, E.F. Nonsense-mediated decay of human HEXA mRNA. Mol. Cell. Biol. 21, 5512–5519 (2001).

    Article  CAS  Google Scholar 

  45. Wishart, D.S. et al. HMDB 3.0—the Human Metabolome Database in 2013. Nucleic Acids Res. 41, D801–D807 (2013).

    Article  CAS  Google Scholar 

  46. Engelke, U.F. et al. NMR spectroscopic studies on the late onset form of 3-methylglutaconic aciduria type I and other defects in leucine metabolism. NMR Biomed. 19, 271–278 (2006).

    Article  CAS  Google Scholar 

  47. Valianpour, F., Abeling, N.G., Duran, M., Huijmans, J.G. & Kulik, W. Quantification of free sialic acid in urine by HPLC–electrospray tandem mass spectrometry: a tool for the diagnosis of sialic acid storage disease. Clin. Chem. 50, 403–409 (2004).

    Article  CAS  Google Scholar 

  48. van der Ham, M. et al. Liquid chromatography–tandem mass spectrometry assay for the quantification of free and total sialic acid in human cerebrospinal fluid. J. Chromatogr. B Analyt. Technol. Biomed. Life Sci. 878, 1098–1102 (2010).

    Article  CAS  Google Scholar 

  49. Jansen, J.C. et al. CCDC115 deficiency causes a disorder of Golgi homeostasis with abnormal protein glycosylation. Am. J. Hum. Genet. 98, 310–321 (2016).

    Article  CAS  Google Scholar 

  50. van Scherpenzeel, M., Steenbergen, G., Morava, E., Wevers, R.A. & Lefeber, D.J. High-resolution mass spectrometry glycoprofiling of intact transferrin for diagnosis and subtype identification in the congenital disorders of glycosylation. Transl. Res. 166, 639–649 (2015).

    Article  CAS  Google Scholar 

Download references


We thank M. Filocamo at the Gaslini Biobank (Genoa, Italy) for a fibroblast line for patient 1. We thank A. Reymond (CIG, FBM, Université de Lausanne) and his laboratory for lymphocyte immortalization. We thank C. Chiesa for Sanger sequencing and sample handling and shipment; S. de Boer for excellent technical assistance; B. Toh at the University of British Columbia for metabolic sample handling; X. Han for Sanger sequencing; B. Sayson for consenting and data management; M. Higginson for DNA extraction and sample handling; and A. Ghani for administrative assistance. We also thank R. Houben for skillfully preparing Figure 4 and A. Bandi for all other figures. We are grateful to our clinical colleagues in Dolo, Genoa, Lausanne, Manchester, Paris, Reggio Emilia, Tokyo, Treviso, and Vancouver for patient management. A.S.-F. dedicates this paper to the memory of Paolo Durand who pointed out the relationship between sialic acid metabolism and IDD to him in 1980. Finally, we wish to thank the patients reported here as well as their parents for the enthusiasm they showed for our research efforts, for their patience, which was challenged by the studies lasting many years, and for their repeated donation of biological samples. They have been the source of continuous motivation for us.

This work has been supported by funding from the Leenaards Foundation in Lausanne, Switzerland; the Faculty of Biology and Medicine of the University of Lausanne; the BC Children's Hospital Foundation (Treatable Intellectual Disability Endeavour in British Columbia: First Collaborative Area of Innovation); Genome BC (grant SOF-195); the Rare Diseases Foundation; the Rare Diseases Models and Mechanisms Network; the Canadian Institutes of Health Research (grant 301221); and the Dutch Organization for Scientific Research, ZONMW (Medium Investment Grant 40-00506-98-9001 and VIDI Grant 91713359 to D.J.L.). The zebrafish studies were supported by funding to X.-Y.W. from the Canadian Rare Disease Models and Mechanisms Network, the Brain Canada Foundation, the Natural Sciences and Engineering Research Council of Canada (NSERC), and the Canada Foundation for Innovation (CFI). The informatics infrastructures were supported by Genome BC and Genome Canada (ABC4DE Project) as well as by the Vital-IT Project of the Swiss Institute of Bioinformatics (SIB; Lausanne, Switzerland). C.J.R. is funded by a Canadian Institutes of Health Research New Investigator Award. C.D.M.v.K. is a recipient of the Michael Smith Foundation for Health Research Scholar Award (Vancouver, Canada). E.G. is supported by a Marie Skłodowska-Curie fellowship (MSCA-IF-661491).

Author information

Authors and Affiliations



C.D.M.v.K., L.B., S. Unger, R.A.W., and A.S.-F. conceived the study and coordinated and supervised the different teams. A.S.-F., L.B., C.D.M.v.K., T.D., A.C., M.I.V.A., C.J.R., J.H., L.G., L.T., V.C.-D., D.H., D.D., C.B., I.M., and S. Uchikawa recruited the patients, reviewed the clinical and radiographic features, and obtained biological materials from patients. A.S.-F., S. Unger, and G.N. reviewed the radiographic data. J.R. performed the bone marrow studies. Andrea Rossi reviewed the cerebral imaging. K. Harshman, B.J.S., B.C.-X., S.B., B.R.-B., H.R., C.R., M.T.-G., W.W.W., and A.d.B. were responsible for exome sequencing, haplotype reconstruction, Sanger sequencing, database studies, and mRNA–cDNA studies. R.A.W., L.A.J.K., E.v.d.H., and U.F.E. performed the metabolomics studies. Antonio Rossi studied ManNAc incorporation in fibroblasts. T. Hennet performed the lectin binding studies. A.A., K. Huijben, F.Z., and D.J.L. performed the NANS enzyme assays. D.J.L., A.A., T. Heisse, and T.B. studied the incorporation of sialic acid precursors in lymphocytes and fibroblasts. E.G. and G.S.-F. obtained the NANS three-dimensional model and mapped the affected amino acid residues. X.-Y.W. and K.B.-A. generated and phenotyped the zebrafish model. C.D.M.v.K. and A.S.-F. prepared the manuscript with contributions from all co-authors. All co-authors edited and reviewed the final manuscript.

Corresponding authors

Correspondence to Clara D M van Karnebeek, Ron A Wevers or Andrea Superti-Furga.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Integrated supplementary information

Supplementary Figure 1 Brain magnetic resonance imaging in patient 9 at age 3.6 years.

(ad) Axial T2-weighted images show a marked degree of ventriculomegaly. Note the diencephalic–mesencephalic junction dysplasia, characterized by a lack of separation between the hypothalamus and midbrain (arrowheads in a). In the nucleobasal region, bilaterally, there are dilated perivascular spaces (arrowheads in b) and an abnormal morphology of the basal nuclei, with prominent thalami (labeled T in c) and maloriented putamen and caudate heads (labeled P and C, respectively, in c). Note also the bilateral abnormal orientation of the posterior arms of the sylvian fissure (empty arrows in d). (e) An axial T1-weighted image obtained with a volumetric technique shows thickening of the left perisylvian cortex, consistent with polymicrogyria. Cortical abnormality is less prominent controlaterally, despite the abnormal orientation of the sylvian fissure. (f) A left parasagittal T1-weighted image shows abnormal orientation of the sylvian fissure (arrows), which is continuous with the sulci of the convexity without a normal posterior delimitation; this pattern, which was also visible controlaterally (data not shown), is typical of perisylvian polymicrogyria. (g) A midsagittal T1-weighted image shows shortened, hypoplastic corpus callosum with a thin splenium (thin arrows) and lacking a proper rostrum (thick arrow); also note the absence of a well-defined anterior commissure (arrowhead).

Supplementary Figure 2 Capillary electrophoresis analysis of NANS cDNA retrotranscribed and amplified from RNA extracted from cell cultures.

(a) Schematic of the exon–intron structure of the NANS gene. Asterisks indicate mutations with a putative effect on exon splicing (see Table 1 for details): EXins: c.385_386insT, exonic single-nucleotide insertion producing a frameshift and creating a premature termination codon; SPLko: c.488+1G>T, a canonical splice donor site mutation; INTindel: c.449–10delGATTACinsATGG, an intronic indel 5′ of exon 4. (b) Pedigrees of patients 1, 3, and 4, and corresponding capillary electrophoresis traces of semiquantitative RT-PCRs spanning all analyzed NANS mutations. We assessed unprocessed PCR products obtained with the same primer pairs and allowing the simultaneous ampli-fication of the wild-type and the mutant mRNA (cDNA) forms, indicated on the right, within the same reaction. See the main text for discussion of the results.

Supplementary Figure 3 Expression of NANS in human brain as extracted from the Brainspan database.

In brain, NANS is expressed at significantly higher levels in the thalamus than in other brain regions (top) ( Expression seems to be highest in the dorsal thalamus (bottom), which is an important relay station for the limbic circuit (The Human Nervous System 439–468 Academic Press, 1990) and participates in learning and memory processes (J. Neurosci. 34, 15340–15346, 2014), which might contribute to the developmental delay in patients with NANS deficiency.

Supplementary information

Supplementary Text and Figures

Supplementary Figures 1–3, Supplementary Tables 1–5 and Supplementary Note. (PDF 2775 kb)

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

van Karnebeek, C., Bonafé, L., Wen, XY. et al. NANS-mediated synthesis of sialic acid is required for brain and skeletal development. Nat Genet 48, 777–784 (2016).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing