IL1R1 encodes the human gene, Interleukin 1 receptor, type I. It may also be known as: Interleukin-1 receptor type 1; IL-1R-1; IL-1RT-1; IL-1RT1; CD121 antigen-like family member A; Interleukin-1 receptor alpha; IL-1R-alpha; Interleukin-1 receptor type I; CD antigen CD121a; CD121A; D2S1473; IL1R. The encoded protein has an amino acid length of 569 and a mass of 65.4 kDa. Other isoforms may exist. IL1R1 is a member of the Interleukin-1 receptor family. Homologs of this gene exist in other organisms, including: Mouse.