BTBD3 (BTB domain containing 3) is a protein-coding gene that serves as a key regulator of neuronal development and dendritic morphogenesis. In the developing brain, BTBD3 acts as a regulator of dendritic field orientation during sensory cortex development and directs dendrites toward active axon terminals [based on UniProt annotation]. The gene appears to play important roles in thalamic nuclear regionalization, as evidenced by its expression patterns in the thalamic mantle layer where it contributes to establishing the molecular thalamic protomap 1. BTBD3 has been implicated in several psychiatric and neurological conditions. Genome-wide association studies have identified significant associations between BTBD3 variants and obsessive-compulsive disorder, with one variant near BTBD3 exceeding genome-wide significance thresholds in trio analysis 2. The gene has also been associated with temperament traits, specifically showing significant association with the Harm Avoidance-Fatigability scale in personality studies 3. Additionally, BTBD3 serves as a target for multiple microRNAs including miR-9, miR-181c, and let-7i, suggesting its expression is tightly regulated during both normal development and disease states 4 5. The gene's involvement in neurodevelopmental processes and its dysregulation in psychiatric disorders highlight its clinical significance in understanding brain development and mental health conditions.