A 7-month-old boy is brought to the physician by his parents due to irritability and white patches in his mouth. His past medical history is significant forchronic diarrhea and failure to thrive. The child is small for his age and ill-appearing. He is found to have a low blood T-lymphocyte count and severely decreased serum immunoglobulin. After thorough evaluation, an experimental treatment is proposed to his parents. The therapy consists of infecting the patient's cells with a retroviral vector containing the gene for a protein that is deficient in this patient. Which of the following proteins is most likely coded by this gene?

Question

A 7-month-old boy is brought to the physician by his parents due to irritability and white patches in his mouth.  His past medical history is significant forchronic diarrhea and failure to thrive.  The child is small for his age and ill-appearing. He is found to have a low blood T-lymphocyte count and severely decreased serum immunoglobulin. After thorough evaluation, an experimental treatment is proposed to his parents.  The therapy consists of infecting the patient's cells with a retroviral vector containing the gene for a protein that is deficient in this patient.  Which of the following proteins is most likely coded by this gene?

Quizplus · Accepted Answer

Eductional Objective: The second most common cause of severe combined immunodeficiency is autosomal recessive deficiency of adenosine deaminase, an enzyme necessary for the elimination of excess adenosine within cells.  Toxic levels of adenosine accumulate within lymphocytes in this condition, leading to lymphocyte cell death and resultant cellular and humoral immunodeficiency.  Patients with this condition can be treated with hematopoietic cell transplantation or gene therapy.

A 7-Month-Old Boy Is Brought to the Physician by His