CYFIP2 is a conserved protein with critical roles in neuronal development and immune regulation. As a key component of the WAVE regulatory complex, CYFIP2 regulates actin cytoskeleton dynamics essential for neuronal morphology and circuit formation 1. Beyond its canonical actin-regulatory function, CYFIP2 regulates membraneless organelles involved in mRNA processing and translation, and influences eIF2α phosphorylation to modulate protein synthesis 2. CYFIP2 also mediates p53-dependent apoptosis and T-cell adhesion [UniProt annotation supported by functional studies]. Clinically, de novo CYFIP2 variants cause neurodevelopmental disorders, particularly developmental and epileptic encephalopathy and West syndrome, characterized by early-onset intractable seizures, intellectual disability, and microcephaly 1. CYFIP2 deficiency impairs visual function through altered retinal ganglion cell properties 3, mechanistically connecting this gene to sensory neurodevelopmental impairments. In cancer biology, CYFIP2 serves as a multifaceted biomarker. Downregulation predicts poor prognosis in clear cell renal carcinoma and correlates with immune infiltration 4. Conversely, CYFIP2 expression associates with enhanced immune cell infiltration and improved immunotherapy responses in pancreatic and lung cancers 56. In rheumatoid arthritis, CYFIP2 emerged as a core diagnostic gene, suggesting broader roles in autoimmune pathogenesis 7.