CYLD also known as cylindromatosis 1, USPL2, CYLD1 is encodes a cytoplasmic protein with three cytoskeletal-associated protein-glycine-conserved (CAP-GLY) domains that functions as a deubiquitinating enzyme. CYLD plays a crucial role in cellular signaling pathways by acting as a deubiquitinating enzyme, essential for regulating protein degradation and maintaining cellular homeostasis. This function helps prevent misfolded protein accumulation and modulates signaling molecule activity, influencing cell proliferation and apoptosis. CYLD gene mutations can lead to familial cylindromatosis, characterized by multiple benign skin tumors called cylindromas, which may become infected and cause significant disfigurement and discomfort.