A 3 year old male presents with a skin rash and epistaxis. He has had several, severe sinopulmonary infections. A careful history reveals that his maternal uncle died of bleeding complications following an emergency cholecystectomy. What additional findings are likely in this case?

This clinical scenario is typical for Wiskott-Aldrich syndrome. This is a sex-linked recessive disorder presenting with the triad of thrombocytopenia, eczema, and recurrent sinopulmonary infections. Serum IgM levels are low but IgG, IgA, and IgE levels are increased. Patients have a defective response to polysaccharide antigens, which is due to a cytoskeletal defect in T cells that inhibits their binding to B cells. A CD4/CD8 ratio of < 1.5:1 is the pattern seen in AIDS due to selective tropism of the CD4+ T-helper cell population. Cerebellar ataxia is pa of the ataxia-telangiectasia syndrome. The ataxia develops between age 2 and 5. The defect is associated with a DNA repair enzyme deficiency. Elevated platelet count and increased serum levels of IgG, IgA, and IgE is not associated with a paicular syndrome. Polyclonal gammopathies result in an increase in immunoglobulin of more than one class. This benign alteration is frequently seen in viral or bacterial infections. Thrombocythemia may be associated with a myeloproliferative syndrome or with a secondary reactive process. Ref: Brooks G.F., Carroll K.C., Butel J.S., Morse S.A., Mietzner T.A. (2013). Chapter 8. Immunology. In G.F. Brooks, K.C. Carroll, J.S. Butel, S.A. Morse, T.A. Mietzner (Eds), Jawetz, Melnick, & Adelberg's Medical Microbiology, 26e.