Orphanet: GM3 synthase deficiency

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GM3 synthase deficiency

Disease definition

GM3 synthase deficiency is a rare congenital disorder of glycosylation due to impaired synthesis of complex ganglioside species initially characterized by irritability, poor feeding, failure to thrive and early-onset refractory epilepsy, followed by postnatal growth impairment, severe developmental delay or developmental regression, profound intellectual disability, deafness and abnormalities of skin pigmentation (mostly freckle-like hyperpigmented and depigmented macules). Visual impairment due to cortical atrophy (visible on magnetic resonance imaging), choreoathetosis and hypotonic tetraparesis usually appear gradually. Dysmorphic facial features may be associated.


Classification level: Disorder
  • Synonym(s):
    • ST3GAL5-CDG
  • Prevalence: -
  • Inheritance: -
  • Age of onset: -
  • ICD-10: E77.8
  • OMIM: 609056
  • UMLS: -
  • MeSH: -
  • GARD: -
  • MedDRA: -
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