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: Answer is B (Decreased levels of a fetoproteins) Persistance of very high levels of oncofetal proteins, including alpha fetoproteins and carcinoembryonic antigens is of diagnostic value - Harrison All other features mentioned as options are characteristics of Ataxia-telengiectasia