IBTK (Inhibitor Of Bruton Tyrosine Kinase) is a Protein Coding gene. Diseases associated with IBTK include Agammaglobulinemia. Among its related pathways are B cell receptor signaling pathway (KEGG). Bruton tyrosine kinase (BTK) is a protein tyrosine kinase that is expressed in B cells, macrophages, and neutrophils. The protein encoded by IBTK binds to BTK and downregulates BTK’s kinase activity. In addition, the encoded protein disrupts BTK-mediated calcium mobilization and negatively regulates the activation of nuclear factor-kappa-B-driven transcription. IBTK has a pseudogene on chromosome 18. Alternative splicing results in multiple transcript variants encoding distinct isoforms.