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: Medicine
Ataxia telangiectasia is chracterised by all of the following except: 
Select and explain. 
A. Chronic sinopulmonary disease, B. Decreased level of a-fetoprotein, C. Chromosomal breakage, D. IgA deficiency
B: Decreased level of a-fetoprotein
Answer: B: Decreased level of a-fetoprotein 
Explanation: Increased levels of a fetoproteins is seen in ataxia telangiectasia. Ref: Harrison's Principles of Internal Medicine, 17th Edition O P Ghai Essential Pediatrics, 6th Edition