The effect of BTK gene mutations on protein function and relation with genotype and phenotype at Bruton disease

The protein encoded by BTK gene plays a crucial role in B-cell development. Mutations in this gene cause X-linked agammaglobulinemia , which is an immunodeficiency characterized by the failure to produce mature B lymphocytes, and associated with a failure of Ig heavy chain rearrangement. Bruton's tyrosine kinase (Btk), a Tec-family tyrosine kinase, is essential for B-cell function. People suffering from a genetic disease called X-linked agammaglobulinemia have fewer fully mature B-cells than most people and are extremely susceptible to bacterial infections. The disease is caused by mutations in the gene (Btk), which is involved in B-cell development. We have studied the roles of individual mutations in the domains of BTK gene and determined the structure of the mutations. This structure allows us to discuss how the point mutations may inactivate BTK and subsequently cause XLA. The mutations is interpreted in terms of the genomic organization of the BTK gene and the disease course in individual patients. The database of XLA‐causing identified mutations in Btk, the BTKbase and HGMD It has been reported.