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
Which of the following disease is associated with adenosine deaminase deficiency? 
Select and explain. 
A. Chronic granulomatous disease, B. X-linked agammaglobulinemia, C. Severe combined immunodeficiency (SCID), D. Transient hypogammaglobulinemia of infancy
C: Severe combined immunodeficiency (SCID)
Answer: C: Severe combined immunodeficiency (SCID) 
Explanation: Adenosine deaminase deficiency is associated with the development of severe combined immunodeficiency. Adenosine deaminase enzyme conves adenosine and deoxyadenosine into inosine and deoxyinosine. In the absence of ADA, high intracellular levels of adenosine, deoxyadenosine, and their toxic phosphorylated metabolites cause apoptosis of lymphoid precursors, resulting in the viual absence of T lymphocytes, that is usually associated with marked reduction of B and NK lymphocytes. Ref: Williams Hematology, 8th Edition, Chapter 82; Harrisons Internal Medicine, 18th Edition, Chapter 316