Familial variable immunodeficiency: autosomal dominant pattern of inheritance with variable expression of the defect(s).

In 1963, Rosen and Bougas reported the case of a woman with recurrent infection, marked elevation of 19S, and virtual absence of 7S gamma globulin. Recently, members of her family were found to have similar abnormalities: Ten of the 37 family members tested had elevated levels of serum IgM accompanied by a combined deficiency of IgG and IgA in three, and by a deficiency of either IgG or IgA in two. In five, an increase in IgM was the sole abnormality. Two children had deficiencies of IgG and IgA with normal serum levels of IgM. Ten of the 12 affected individuals had no IgD detectable by radial immunodiffusion and six had a low percentage of IgG-bearing B lymphocytes. A lack of correlation between the immunochemical abnormalities and either the presence or severity of clinical illness was observed. The presence of immunodeficiency in three generations and in both sexes of this family suggests an autosomal dominant mode of inheritance with variable penetrance of the defect.