GM3 synthase deficiency

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GM3 synthase deficiency

ORPHA:370933Disease

Also called ST3GAL5-CDG

What it is

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.

Key facts

Inheritance
Autosomal recessive
Classified as
Disease

Gene

ST3GAL5Disease-causing germline mutation(s) (loss of function)

ICD-10 codes

E77.8filed under a broader ICD-10 category — shared with 56 other rare diseases

ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.

Related health topics

Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.

Cross-references

GARD 12059MONDO 0018274OMIM 609056

Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.

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