UGDH (UDP-glucose 6-dehydrogenase) is a cytosolic hexameric enzyme that catalyzes the conversion of UDP-glucose to UDP-glucuronic acid (UDP-GlcUA), a critical metabolic step with dual roles in normal physiology and disease 1. Primary function: UGDH is essential for biosynthesis of complex glycosaminoglycans including chondroitin sulfate and heparan sulfate, and is required for proper embryonic development and brain/neuronal development 2. Mechanism: The enzyme catalyzes two NAD+-dependent oxidation reactions converting the C6 hydroxyl of UDP-glucose to a carboxylate, generating UDP-GlcUA required for hyaluronan, proteoglycans, and glucuronide conjugate production 2. Disease relevance: Biallelic UGDH variants cause developmental and epileptic encephalopathy (DEE) with reported effects on cardiac valve and brain development, and dystroglycanopathy 2. Clinical significance: UGDH is upregulated in multiple cancer types and promotes tumor progression through multiple mechanisms: tyrosine phosphorylation enhances lung cancer metastasis 3, while post-translational modifications (lactylation, O-GlcNAcylation) regulate its activity and extracellular matrix remodeling to suppress anti-tumor immunity [PMID:40150862; 47]. UGDH expression correlates with chemotherapy resistance in colorectal and hepatocellular carcinoma [PMID:40311992; 54], positioning it as both a prognostication marker and therapeutic target in oncology.