Abnormal humoral immune function with defective antibody production and low circulating B-cell numbers are the hallmark of agammaglobulinemia. In many of these patients, a recessive X-linked pattern of inheritance is noted, and the underlying molecular defect resides within a variety of aberrations in the BTK gene; however, a similar phenotype in females and an inability to demonstrate BTK abnormalities in some males suggested the involvement of other genes. Indeed, in recent years, a better understanding of B-lymphocyte development and function has permitted the determination of the etiology in some of these autosomal inherited agammaglobulinemia patients.

This article summarizes the known cases of autosomal recessive human agammaglobulinemia as well as other putative defects in B-cell maturation and activation predicted by animal models.