ST8SIA5 encodes an alpha-2,8-sialyltransferase responsible for synthesizing complex gangliosides including GD1c, GT1a, GQ1b, GP1c, and GT3 from precursor molecules [PMID:UniProt]. The enzyme functions in glycosphingolipid biosynthesis within the Golgi membrane, catalyzing the addition of sialic acid residues to oligosaccharide chains through its alpha-N-acetylneuraminate alpha-2,8-sialyltransferase activity. ST8SIA5 expression is dysregulated in multiple disease contexts. In breast cancer, ST8SIA5 is significantly downregulated and participates in the glycosphingolipid biosynthesis pathway, suggesting altered ganglioside metabolism may contribute to cancer progression 1. The gene is associated with obesity phenotypes; DNA methylation at a CpG site (cg16170243) within the ST8SIA5 locus on chromosome 18.2 correlates with waist circumference in healthy individuals 2. Higher ST8SIA5 expression correlates with poor prognosis in stomach adenocarcinoma, with lower expression levels associated with improved patient survival 3. Variants in ST8SIA5 (rs79491311) associate with thinness-related phenotypes and interact with dietary factors and exercise in body weight regulation 4. In intervertebral disc degeneration, the lncRNA lnc-ST8SIA5-1:2 is upregulated in senescent nucleus pulposus cells 5, and ST8SIA5 represents a hub gene in valvular atrial fibrillation pathogenesis 6. These findings suggest ST8SIA5 plays roles beyond glycosphingolipid metabolism, potentially influencing metabolic disease, aging, and cardiac pathology.