ST8SIA3

Chr 18

ST8 alpha-N-acetyl-neuraminide alpha-2,8-sialyltransferase 3

Also known as: SIAT8C, ST8SiaIII

NCBI Gene: 51046 ENSG00000177511 UniProt: O43173

This highly constrained gene encodes a sialyltransferase that catalyzes the transfer of sialic acid to form oligosialic and polysialic acid modifications on N-linked glycoproteins and glycolipids, particularly in the striatum where it regulates protein distribution in lipid rafts. Mutations cause autosomal recessive intellectual disability with seizures and spasticity, typically presenting in early childhood. The gene shows strong intolerance to loss-of-function variants (pLI 0.86, LOEUF 0.41), suggesting haploinsufficiency is not well tolerated.

ResearchSummary from RefSeq, UniProt

Enables alpha-N-acetylneuraminate alpha-2,8-sialyltransferase activity and identical protein binding activity. Involved in several processes, including ganglioside biosynthetic process; glycoprotein metabolic process; and sialylation. Predicted to be located in Golgi membrane. [provided by Alliance of Genome Resources, Jul 2025]

ResearchGenerating clinical summary…

Clinical highlights

Interpreting a novel variant

This gene is strongly intolerant of loss-of-function variation in the population, so LoF variants warrant close attention. No curated mechanism annotation is available — see the mechanism card for the computational prediction and its caveats.Based on population constraint only.

Active trials

Pubs (1 yr)

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P/LP submissions

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P/LP missense

0.41

LOEUF

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Mechanism

Some data sources returned errors (1)

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