A mutation in Bruton's tyrosine kinase as a cause of selective anti-polysaccharide antibody deficiency

Children and adults can have recurrent infection with invasive encapsulated bacterial pathogens such as Streptococcus pneumoniae as a result of a sele ctive inability to respond to polysaccharide antigens. We have identified a mutation in the gene encoding Bruton's tyrosine kinase in a male patient w ith selective anti-polysaccharide antibody deficiency.