This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Structure and function of protein, Subject name: Biochemistry
[{'content': 'The first gene therapy (somatic enzyme) was successfully done in \nSelect and explain. \nA. SCID, B. Phenylketonuria, C. Thalassemia, D. Cystic fibrosis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Deficiency of adenosine deaminase, a condition that affects lymphocytes paicularly, was the first disease to be treated by gene therapy. Deficiency of adenosine deaminase accounts for 15% of all cases of severe combined immunodeficiency (SCID)In 1990, Dr. William French Anderson introduced a new copy the gene, carried on a retroviral vector, into a 4-year-old girl suffering from severe combined immunodeficiency (Bubble boy disease).Ref: Harper 30th edition pg: 699', 'role': 'assistant'}]