Question

Explain enzyme replacement therapy to treat adenosine deaminase deficiency. Mention two disadvantages of this procedure.

Answer 1

Enzyme replacement therapy or ERT is a medical treatment which includes replacing an enzyme in patients in whom that particular enzyme is deficient or absent. This is done by giving the patient an intravenous infusion containing that enzyme.

Adenosine deaminase (ADA) is one form of SCID, which is a disease deficiency causing malfunctioning of the immune system. The disease is caused by a mutation in a gene on chromosome 20 which codes for the enzyme ADA. So, to treat ADA deficiency, enzyme replacement therapy is used which involves repeated injection of the ADA enzyme.

However, there are certain disadvantages:

• Not all patients are suited for this treatment.
  
• Some organs and tissues are treated more readily than others and there are problems with gauging efficacy.
  
• They are expensive, thereby limiting access to patients.