X-linked interleukin-1 receptor accessory protein-like 1 (IL1RAPL-1) belongs to the interleukin-1 receptor family. IL1RAPL-1 is detected at low levels in heart, skeletal muscle, ovary, skin, amygdala, and brain (caudate nucleus, corpus callosum, hippocampus, substantia nigra and thalamus). Defects in IL1RAPL1 are the cause of mental retardation X-linked type 21 (MRX21).The synthetic peptide used to raise the antibody Cat. No. 250714 is selected from a sequence within the center region of human IL1RAPL1. For blocking experiments, a 10 to 100 fold molar excess to antibody is recommended.