Question

What is the permanent cure of adenosine deaminase (ADA) deficiency in children?
A. Bone marrow transplantation
B. Enzyme replacement therapy in which functional ADA is given to patient by injection
C. Infusion of genetically engineered lymphocytes (in which functional ADA- cDNA is introduced) into a patient's blood.
D. Introduction of genes isolated from the bone marrow cells which produce ADA, into the cells of the patient at early embryonic stages.

Answer 1

Hint: ADA (adenosine deaminase) is an enzyme present on ADA gene. It is an autosomal recessive disorder. It can diagnose by checking ADA levels in the blood. Isolation of genes from embryos and bone transplantation can be used to treat this disorder.

Complete answer:
Adenosine deaminase is an inherited disorder. It is a metabolic disorder. The mutation in ADA genes causes this disorder. It mainly affects the immune system and causes severe combined immunodeficiency (SCID). It was recognized as the first immunodeficiency disorder. The immune lacks the protection against bacteria, viruses, and fungi. This type of disorder is present in infancy, childhood, adolescence, or adulthood.The growth of the affected children is slower than the healthy children. The development is delayed in affected children.
The Adenosine deaminase enzyme is attached to the ADA gene. If there is a decreased level of ADA in blood then the person has ADA deficiency. Bone marrow transplant, ADA enzyme in PEG vehicle can be used for the treatment of this disorder. The treatment ADA is a very complex process. Enzyme replacement therapy involves the injection of ADA to the patient. Introduction of genes isolated from bone marrow cells, it produces ADA, into the cells of the patient at early embryonic stage. It can only cure permanently with the help of gene therapy.

Hence, the correct answer is option (D).

Note: ADA deficiency is inherited in an autosomal recessive manner in the chromosome. It means that the defect in the gene is responsible for the disorder. It is not sex linked chromosome disorder. ADA enzyme functions to eliminate a molecule called deoxyadenosine. It converts deoxyadenosine to deoxyinosine which is not harmful. The parent of the individual carries one copy of the defective gene.