A 1-Year-Old Boy Is Evaluated for a Suspected Immune Deficiency

Multiple Choice

A 1-year-old boy is evaluated for a suspected immune deficiency.He has a history since birth of eczema,recurrent rashes,and diarrhea.His white blood cell count (WBC) count is 6.75/uL (normal values: 5.0-10.8 × 103 uL) with a normal differential.Platelet count is 35,000 (normal values: 150,000-350,000/uL) ,and the platelets are small.His IgG is 750 mg/dL (normal values: 600-1,500 mg/dL) .IgM is 30 mg/dL (normal values; 75-150 mg/dL) .IgA is 475 mg/dL (normal values: 50-125 mg/dL) .IgE is 750 mg/dL (10-50 mg/dL) .The boy's blood is typed as O-positive,and he does not have anti-A or anti-B antibodies.Flow cytometry performed on his blood shows 11% CD19 (normal values: 5%-20%) and 50% CD3 cells (normal values: 60%-80%) with a normal ratio of CD4:CD8.T-cell function tests are abnormal.This boy most likely has:

A) Bruton's tyrosine kinase deficiency.
B) Wiskott-Aldrich syndrome.
C) DiGeorge anomaly.
D) ataxia telangiectasia.