B4GALT6 (beta-1,4-galactosyltransferase 6) catalyzes the synthesis of lactosylceramide (LacCer) by transferring galactose from UDP-galactose to glucosylceramide 1. LacCer serves as the essential precursor for ganglioside biosynthesis, membrane-bound glycosphingolipids critical for CNS development, neuronal maturation, axonogenesis, and myelination. B4GALT6-derived LacCer regulates astrocyte activation in an autocrine manner and controls microglia/monocyte recruitment through CCL2 and GM-CSF production, contributing to neuroinflammation in multiple sclerosis models 2. Elevated B4GALT6 expression and LacCer levels are detected in MS lesions, making B4GALT6 inhibition a potential therapeutic strategy for neuroinflammatory disorders 2. Beyond CNS functions, B4GALT6 variants associate with thyroid function (FT4 levels) 3, glycemic traits and insulin resistance (HOMA-IR) in African populations 4, and age-related cataract risk through galactose metabolism pathways 5. B4GALT6 alterations in specific brain cell types (hippocampal microglia/neurons, cortical astrocytes) correlate with major depressive disorder pathology 6. These findings establish B4GALT6 as a multifunctional enzyme with significant roles in neuroinflammation, metabolic regulation, and psychiatric disorders, warranting further investigation as a therapeutic target.