Which of the following is a feature of Wiskott-Aldrich syndrome?

Wiskott-Aldrich syndrome is a rare X-linked immunodeficiency disorder that is characterized by a triad of features: eczema, thrombocytopenia (low platelet counts), and immunodeficiency. One of the key immunological abnormalities associated with this condition is hypogammaglobulinemia, which refers to low levels of antibodies (immunoglobulins) in the blood. This deficiency predisposes affected individuals to recurrent infections and can lead to severe complications.

In Wiskott-Aldrich syndrome, the patients often have a decreased ability to generate antibodies in response to infections or immunizations due to the underlying immunologic defect. This is why hypogammaglobulinemia is a hallmark feature of the syndrome.

The other potential choices do not relate to Wiskott-Aldrich syndrome. Excessive hair growth is not associated with this condition and could relate to other disorders or hormonal imbalances. Chronic kidney disease is not a recognized feature of Wiskott-Aldrich syndrome, and myopathy, which refers to muscle disease, is also unrelated. Therefore, identifying hypogammaglobulinemia as a feature aligns perfectly with the immunological compromise that defines this syndrome.