Synonyms: ST3GAL5-CDG
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.
Data from Orphanet are used to provide information on a disease's name, synonym(s), and overview. Reference: Access aggregated data from Orphanet at Orphadata. Orphadata: Free access data from Orphanet. © INSERM 1999. Available on http://www.orphadata.org. Data version April 2026
Newly diagnosed with
GM3 synthase deficiency?
Our RARE Concierge Services Guides are available to assist you by providing information, resources and connections as you navigate your rare disease journey.
Advocacy Organizations
CDG CARE
Our mission is to promote greater awareness and understanding of CDG, to provide information and support to families affected by CDG, and to advocate for and fund scientific research to advance the diagnosis and treatment of CDG.
CDG Canada
CDG Canada supports patients and families affected by Congenital Disorders of Glycosylation (CDG).
Genetic Epilepsy Team Australia
Collaboration of research and care
Louisiana Metabolic Disorders Coalition
We support, educate, and advocate for patients & families affected by metabolic disorders.
Mississippi Metabolics Foundation
Our mission at Mississippi Metabolics Foundation (MMF) is to advocate, educate, and support families in MS affected by genetic metabolic disorders/inborn errors of metabolism (IEM's). MMF promotes initiatives and further advancements in legislation, education, research, clinical trials, studies, therapies, targeted treatments, and eventual cures for IEM’s and all rare diseases.
Rare Epilepsy Network (REN)
Improving outcomes of people with rare epilepsies through an innovative collaborative infrastructure that drives urgent, patient-centered research, educaiton and advocacy.
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Clinical Trials
For a list of clinical trials in this disease area, please click here.