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 characterised 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: Ans. is 'b' i.e., Decreased levels of a fetoproteins Ataxia telangiectasia o Ataxia Telangiectasia (AT) is an autosomal recessive disorder. o It is due to mutation of AT gene located on chromosome 11. o There is defective DNA repair that results in multiple chromosomal breaks. Clinical manifestations o Present in first decase of life. o Feature are : - i) Oculocutaneous telengiectasia ii)Neurological -4 Ataxia, dysahria, extensor plantar response, myoclonic jerks, areflexia, distal sensory deficity. iii) Immunodeficeincy --) Thymic hypoplasia with cellular and humoral (IgA and IgG2) immunodeficeincy. iv) Recurrent pulmonary infections v) Endocrine disorders ---> Tye I DM vi) Premature aging vii) Malignancies Lymphoma, Hodgkin's disease, acute T cell leukemia, breast cancer. and a-feto protein and carcino-embryonic antigen are increased