SPTBN1 encodes βII-spectrin, a ubiquitously expressed cytoskeletal protein that forms micrometer-scale networks associated with plasma membranes and plays critical roles in central nervous system development and function 1. The protein functions as a structural component of the cytoskeleton and serves as an adapter protein for transforming growth factor-β (TGF-β) signaling, facilitating Smad3/Smad4 complex formation 2. βII-spectrin is essential for proper cytoskeleton organization and dynamics, membrane protein localization, and cellular scaffolding 3. Pathogenic heterozygous SPTBN1 variants cause an autosomal dominant neurodevelopmental syndrome characterized by developmental delays, intellectual disability, autistic features, seizures, and behavioral abnormalities 13. These variants lead to haploinsufficiency effects that compromise βII-spectrin stability and disrupt binding to molecular partners 1. Beyond neurodevelopment, SPTBN1 acts as a tumor suppressor in hepatocellular carcinoma by stabilizing SOCS1 and downregulating inflammatory responses 4. The protein also regulates metabolic processes, with therapeutic targeting showing promise for treating diet-induced liver disease and preventing cancer development 56. These findings establish SPTBN1 as a multifunctional protein critical for neurological development and cellular homeostasis.