OLIG3 (oligodendrocyte transcription factor 3) is a basic helix-loop-helix transcription factor that functions in neural cell specification and CNS development 1. In the spinal cord, OLIG3 participates in determining distinct specification programs for neuronal classes and regulating glial and neuronal cell differentiation during development and neural regeneration 2. OLIG3 expression is regulated by multiple signaling pathways including nodal, FGF, retinoic acid, BMP, and hedgehog signals along the dorsoventral axis of the embryonic CNS 1. During human thalamic development, OLIG3 marks the extent and boundaries of the thalamic proliferative zone, serving as a structural marker in the emerging thalamic protomap 3. Disease relevance: OLIG3 variants have been associated with multiple pathological conditions. A missense variant (p.Arg210Gly) in OLIG3 co-segregated with osteoarthritis in a Finnish family and was predicted pathogenic, suggesting a role in cartilage and bone physiology 4. OLIG3 at the 6q23 locus is a confirmed rheumatoid arthritis susceptibility gene 5, with the OLIG3/TNFAIP3 locus showing significant association with RA particularly in autoantibody-positive patients 6. GWAS studies identified OLIG3 association with tau neuropathology in progressive supranuclear palsy 7. These findings underscore OLIG3's broader role in immune-inflammatory and neurodegenerative disease susceptibility.