Gene therapy is an evolving medical technology used to treat genetic disorders. Depending on the target cell type, gene therapy can be classified as either somatic or germ-line.
(i) State which type of gene therapy (somatic or germ-line) has effects that can be inherited by the patient's offspring, and explain why. (ii) Compare somatic and germ-line gene therapy with respect to:
Some attempts at gene therapy using viral vectors to integrate a therapeutic gene into a host chromosome have resulted in unintended changes to the expression of other genes on that chromosome. Explain how inserting a new gene sequence into a chromosome could affect the functioning of neighboring genes.
Cystic fibrosis is a recessive disorder that can potentially be treated by introducing a functional copy of the normal allele into lung epithelial cells.
In contrast, Huntington's disease is a terminal neurological disorder caused by a dominant allele that codes for a mutated, toxic form of the huntingtin protein.
Suggest why standard gene addition therapy (introducing a normal, functional copy of the gene) is unlikely to be an effective treatment for Huntington's disease.
