Statement I: ADA deficiency disorder is caused due to the excessive synthesis of gene for adenosine deaminase.
Statement II: It affects the human immune system.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Only statement II is correct.
Statement I: ADA deficiency disorder is caused due to the excessive synthesis of gene for adenosine deaminase. — False. ADA deficiency is caused by the deletion of the gene for the enzyme adenosine deaminase. The gene is missing, so the enzyme is not made at all; nothing is made in excess.
Statement II: It affects the human immune system. — True. Adenosine deaminase is needed for the immune system to work. Without it, the body cannot fight infections well. In 1990, a 4-year-old girl with this disorder received the first clinical gene therapy.
NCERT Extract:
Gene Therapy – “… The first clinical gene therapy was given in 1990 to a 4-year old girl with adenosine deaminase (ADA) deficiency. This enzyme is crucial for the immune system to function. The disorder is caused due to the deletion of the gene for adenosine deaminase.”