Although XLA is the most common form of agammaglobulinemia, several other congenital agammaglobulinemias have been identified that are inherited in an autosomal dominant or recessive manner (μ chain, Igα, Igβ, λ5, E47, BLNK, PIK3R1) [4]. This evidence concerns the gene PIK3R1 and agammaglobulinemia.