This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
True about Bloom Syndrome - 
Select and explain. 
A. Decreased IgG, B. Decreased IgM, C. IgA absent, D. Increased IgE
B: Decreased IgM
Answer: B: Decreased IgM 
Explanation: None