Q.ELISA is a technique based on the principles of antigen-antibody reactions. Can this technique be used in the molecular diagnosis of a genetic disorder such as Phenylketonuria?

Step 1. Recall ELISA's operating principle: it works purely on antigen-antibody recognition, detecting a specific antigen or the antibody raised against it in a sample — which is exactly why it is so effective for infections (like HIV) where the body's immune system reacts to a foreign pathogen protein. Step 2. Recall what phenylketonuria (PKU) actually is: a genetic metabolic disorder caused by a mutation in the gene for the enzyme phenylalanine hydroxylase, which leaves the body unable to break down the amino acid phenylalanine properly. Step 3. Compare the two: PKU involves no foreign antigen and provokes no antibody response — the defective enzyme is the patient's own protein, just malfunctioning, so there is nothing for an antigen-antibody assay like ELISA to bind and detect. Step 4. State what would actually work instead: PKU is diagnosed by measuring elevated blood phenylalanine levels biochemically, or …

Compare ELISA's antigen-antibody detection principle against what PKU actually is (a metabolic enzyme-gene defect with no foreig …

• Assuming any 'molecular diagnostic' technique works for any genetic disorder, without checking whether an antigen-antibody reaction is actually involved. …