Based on limited published evidence, SSX2B is an X-chromosome X with unclear intrinsic function in normal physiology. SSX2B has been identified as a fusion partner in synovial sarcoma, where it participates in SS18-SSX2B translocation fusion genes detectable by RNA sequencing 1. Additionally, placental SSX2B expression was identified through transcriptome analysis and Mendelian randomization as potentially causally associated with early childhood BMI trajectories and obesity risk, suggesting a role in developmental growth regulation 2. However, the molecular mechanisms underlying these associations remain unknown.