A rare dysgammaglobulinemia characterized by low or undetectable serum levels of immunoglobulin class D (IgD). It is an uncommon primary antibody deficiency. It is most likely an inherited immunodeficiency. It may be caused by decreased or inefficient production of IgD from progenitor B cells without any corresponding decreases in the other isotypes. Most affected persons are asymptomatic and do not appear to be at increased risk for infection.