This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Single Gene Disorders, Subject name: Pathology
[{'content': 'All of the following statements are true about Wiskott Aldrich syndrome, except: \nSelect and explain. \nA. Autosomal recessive disorder, B. Low serum IgM level, C. Thrombocytopenia, D. Eczema', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Wiskott-Aldrich syndrome X-linked recessive disease Characterized by thrombocytopenia, eczema, and a marked vulnerability to recurrent infection Mutation in gene encoding Wiskott-Aldrich syndrome protein (WASP), which is located at Xp11.23. IgM levels in the serum are low, but levels of IgG are usually normal. Paradoxically the levels of IgA and IgE are often elevated. The only treatment is HSC transplantation.', 'role': 'assistant'}]