Chapter 1, Problem 18P

Researchers have successfully used gene therapy to ameliorate some human genetic diseases by adding a normal gene copy to cells whose genomes originally had only nonfunctional mutant copies of that gene. For example, a form of blindness due to the lack of a single protein called RPE65 has been reversed by introduction of a normal RPE65 gene to cells of the retina of adults.

a.	The success of this gene therapy approach provides us with clues about the role of the RPE65 protein in the retina. Do you think that RPE65 is needed for the proper development of the human eye?
b.	Can you see a potential difficulty in applying this gene therapy approach for diseases like microcephaly?