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
[{'content': "An 8-month-old boy baby is evaluated because of repeated episodes of pneumococcal pneumoniA Serum studies demonstrate very low levels of IgM, IgG, and IgA This patient's condition is related to a deficiency of which of the following proteins? \nSelect and explain. \nA. Adenosine deaminase, B. Class III MHC gene, C. Gamma chain of the IL-2 receptor, D. Tyrosine kinase", 'role': 'user'}, {'content': "Answer: D \nExplanation: As the history is of recurrent infections with bacteria (pneumococcal pneumonia), it indicates primary humoral immunodeficiency. As this is occurring in a 8-month old male child, it indicates X-linked agammaglobulinaemia also called as buon's agammaglobulinaemia. In this disorder there is deficiency of the enzyme tyrosine kinase, which is required for B cell maturation", 'role': 'assistant'}]