SPATA13 (spermatogenesis associated 13) is a guanine nucleotide exchange factor (GEF) that regulates small GTPase signaling with diverse biological roles. As a GEF, SPATA13 activates RAC1 and CDC42 while inhibiting RHOA, thereby controlling cell migration, adhesion dynamics, and cytoskeletal reorganization through PI3K and AKT1-dependent pathways 1. The protein localizes to the nucleus and associates with kinetochore complexes during mitosis, suggesting roles in cell cycle regulation 1. SPATA13 contributes to multiple disease processes. Mutations in SPATA13 cause primary angle-closure glaucoma (PACG), with increased GEF activity dysregulating mitosis in ocular tissues 1. In bone regeneration, circular SPATA13 RNA promotes osteogenic differentiation of periodontal ligament stem cells via a miR-485-5p/BMP7 regulatory axis 2. SPATA13-AS1 variants associate with bronchodilator response in pediatric asthma, particularly in African American populations 34, and SPATA13 emerges as a susceptibility gene for autoimmune thyroid disease 5. In breast cancer, SPATA13 variants show gene-environment interactions with age at menarche for estrogen receptor-positive disease risk 6. In the central nervous system, SPATA13 modulates social behavior and nocturnal activity, with knockout mice showing subordinate social hierarchy and altered voluntary activity 7. Placental SPATA13 expression mediates genetic associations with metabolic traits including waist-hip ratio 8.