GM3 synthase deficiency
Findings
No curated finding names GM3 synthase deficiency yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
GM3 synthase deficiency is characterized by recurrent seizures (epilepsy) and problems with brain development. Within the first few weeks after birth, affected infants become irritable and develop feeding difficulties and vomiting that prevent them from growing and gaining weight at the usual rate. Seizures begin within the first year of life and worsen over time. Multiple types of seizures are possible, including generalized tonic-clonic seizures (also known as grand mal seizures), which cause muscle rigidity, convulsions, and loss of consciousness. Some affected children also experience prolonged episodes of seizure activity called nonconvulsive status epilepticus. The seizures associated with GM3 synthase deficiency tend to be resistant (refractory) to treatment with antiseizure medications.
Definition from the Mondo Disease Ontology (MONDO:0018274), read 2026-09-29. CC BY 4.0.
- Inheritance
- Autosomal recessive inheritance
- Onset and course
- Infantile onset · Neonatal onset
HPO, annotations 2026-09-02
Features
15 features
What the disease is reported to present with, and how often among people who have it — never how often a feature means the disease. HPO, annotations 2026-09-02.
- Bilateral tonic-clonic seizureHPOHP:0002069
- 8 of 8 reported patients
- Developmental regressionHPOHP:0002376
- 8 of 8 reported patients
- Developmental stagnation at onset of seizuresHPOHP:0006834
- 8 of 8 reported patients
- Failure to thriveHPOHP:0001508
- 8 of 8 reported patients
- Global brain atrophyHPOHP:0002283
- 8 of 8 reported patients
- Global developmental delayHPO
Genes
1 gene
Germline variants in the gene encoding each protein, as classified by GenCC submitters, each in their own words. Limited, disputed and refuted submissions are listed too.
- ST3GAL5HGNC:10872
- Definitive · ClinGen · Autosomal recessive · 2022
- Definitive · G2P · Autosomal recessive · 2019
- Strong · Labcorp Genetics (formerly Invitae) · Autosomal recessive · 2023
- Strong · PanelApp Australia · Autosomal recessive · 2025
Where it sits
Other names
10 names
Resolves to: GM3 synthase deficiency
- Also called
- Amish infantile epilepsy syndromedisorder of lactosylceramide alpha-2,3-sialyltransferase activityepilepsy syndrome, infantile-onset symptomaticinfantile-onset symptomatic epilepsy syndrome - developmental stagnation - blindnessinfantile-onset symptomatic epilepsy syndrome-developmental stagnation-blindness syndromelactosylceramide alpha-2,3-sialyltransferase activity diseasesalt & pepper syndromesalt and pepper developmental regression syndromeSPDRSST3GAL5-CDG