Familial Hypogammaglobulinemia With Variable Serum Immunoglobulins: Concordance With Lymphocyte Ecto-5′-Nucleotidase Deficiency

Four male subjects from two generations of a black family were found to have variable expression of hypogammaglobulinemiaand also to be moderately deficient in the lymphocyte plasma membrane enzyme, 5′-nucleotidase. The inheritance pattern of the immune abnormality is compatible with X linkage. The affected patients had normal numbers of complement receptor-bearing lymphocytes, variably depressed proportions of IgM- and IgD-bearing lymphocytes, and impaired ability to synthesize antibody after specific antigenic stimulation. In this family, the 5′-nucleotidase deficiency and the pattern of inheritance suggest that the different types of hypogammaglobulinemia may represent a variable expression of a common underlying genetic abnormality.