A sex-linked agammaglobulinaemia caused by defective B cell function because of a mutation in the gene encoding Bruton's tyrosine kinase (btk, 659 aa), one of the Tec family. Btk interacts with other tyrosine kinases such as fyn, lyn, and hck, which are activated upon stimulation of B- and T-cell receptors. Itk is the T-cell homologue of btk. The exact mechanism by which btk regulates B-cell differentiation is unclear, but btk interacts with the phosphatidyl inositol signalling pathway. Sab selectively inhibits btk.
Subjects: Medicine and Health.