This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immune system, Subject name: Medicine
[{'content': 'All are true about Bloom syndrome except \nSelect and explain. \nA. Decreased levels of Igg, B. (downward arrow) IgM, C. Ig A absent, D. Raised IgE leveis', 'role': 'user'}, {'content': "Answer: A \nExplanation: Bloom's syndrome malignancies-Leukaemia, tongue, oesophageal, colonic, Wilms'tumourAR BLM gene Ref Davidson 23rd edition pg 587", 'role': 'assistant'}]