Clinical Definition Hypogammaglobulinemia is a decreased level of immunoglobulins (i.e., antibodies). Because of the decrease in disease-fighting immunoglobulins, hypogammaglobulinemia can cause an increased susceptibility to certain diseases and infections. Although its etiology is not always known, it may be present from birth or acquired later in life. In Our Own Words Hypogammaglobulinemia is a condition…