Tumor necrosis factor receptor superfamily member 27, also known as XEDAR and EDA2R, is a type III transmembrane protein of the TNFR superfamily. EDA2R consists of extracellular domain (ECD) with 3 cysteine-rich repeats and a single transmembrane domain but lacks an N-terminal signal peptide. EDA2R is widely expressed, notably in embryonic basal epidermal cells and maturing hair follicles. Even though it does not contain a cytoplasmic death domain, EDA2R can associate with Fas and induce EDA-A2 dependent apoptosis. Its transcription is directly induced by p53, and it mediated cell death is p53 dependent. it is down-regulated in breast, colon, and lung cancers, particularly in cases with p53 mutations. It also plays a role in EDA-A2 induced skeletal muscle degeneration and osteoblast differentiation. Mutations in the EDA gene are associated with the X-linked form of Hypohidrotic Ectodermal Dysplasia (HED), a disease typically characterized by abnormal hair, teeth and sweat glands.