Identification of a new Bruton’s tyrosine kinase (BTK) mutation associated with a mild phenotype in a child with X‐linked agammaglobulinemia (XLA)

Summary This study reports a new X‐linked agammaglobulinemia (XLA) mutation and its phenotypic features in a 6½‐year‐old boy. Different clinically defined subtypes of XLA may exist according to different genetic alterations and to other defect signalling molecules or pathways of B cell maturation.