Sialuria: Ninth Patient Described Has a Novel Mutation in GNE

  • Noelia Nunez Martinez
  • Michelle Lipke
  • Jacqueline Robinson
  • Bridget WilckenEmail author
Research Report
Part of the JIMD Reports book series (JIMD, volume 44)


Sialuria is a rare autosomal dominant inborn error of metabolism characterized by cytoplasmic accumulation and urinary excretion of gram quantities of free sialic acid due to failure of feedback inhibition of the rate-limiting enzyme in the sialic acid synthesis pathway, UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE/MNK). To date, eight cases had been published worldwide, all with heterozygous missense variants at the allosteric site, specifically at Arginine 294 (formerly 263) and Arginine 297 (formerly 266) of GNE. The described cases so far have rather homogeneous clinical features which include developmental delay, mildly coarse features, hepatomegaly and prolonged neonatal jaundice. The apparent rarity of this disorder is hypothesized to be due to the variable and sometimes transient nature of the clinical features and to the absence of routine testing for urinary sialic acids. Here we present the ninth case of sialuria diagnosed in a child investigated because of clinical signs and symptoms and furthermore describe a novel pathogenic variant in the associated gene, GNE.


GNE Hepatomegaly Sialic acids Sialuria UDP acetylglucosamine-2-epimerase 



The authors would like to thank Dr. Marjan Huizing, Professor William Gahl and Professor Edwin Kirk for helpful discussion, Dr. Tim Wood for the cell fractionation and Samuel Wang, who did an initial literature search.


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Copyright information

© Society for the Study of Inborn Errors of Metabolism (SSIEM) 2018

Authors and Affiliations

  • Noelia Nunez Martinez
    • 1
  • Michelle Lipke
    • 2
  • Jacqueline Robinson
    • 1
  • Bridget Wilcken
    • 1
    • 3
    Email author
  1. 1.Centre for Medical GeneticsSydney Children’s HospitalRandwickAustralia
  2. 2.Queensland Lifespan Metabolic Medicine ServiceLady Cilento Children’s HospitalSouth BrisbaneAustralia
  3. 3.University of SydneyCamperdownAustralia

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