What are the major hurdles for the success of gene therapy?
A. Short-lived nature – Before gene therapy can become a permanent cure for a condition, the therapeutic DNA introduced into target cells must remain functional & the cells containing the therapeutic DNA must be stable. Problems with integrating therapeutic DNA into the genome & the rapidly dividing nature of many cells prevent it from achieving long-term benefits. Patients require multiple treatments.
B. Immune response – Any time a foreign object is introduced into human tissues, the immune system is stimulated to attack the invader. Stimulating the immune system in a way that reduces gene therapy effectiveness is possible.
C. Multigene disorders – Some commonly occurring disorders, such as heart disease, high blood pressure, Alzheimer's disease, arthritis, & diabetes, are affected by variations in multiple genes, which complicate gene therapy.
D. Some therapies may breach the Weismann barrier (between soma and germ-line) protecting the testes, potentially modifying the germline, falling afoul of regulations in countries that prohibit the latter practice.
The major risks for gene therapy include:
A. Gene therapy can trigger the immune response in the patient, that could be harmful to them. Retroviruses has raised skepticism about their safety. Deactivated viruses are really deactivated?
B. Viral vectors may cause toxicity, infection, inflammation, etc.
C. Gene therapy may cause off-target effects— there is a risk that the new gene will insert itself into the path of another gene, disrupting its activity, or cause insertional mutagenesis.
D. Gene therapy may cause chronic granulomatous disease and cancer.
Ethicalissues and concernswithgenetherapyare:
A. Howcan"good" and "bad"usesofgenetherapybedistinguished?Whatactuallyhappenswhenthingsgowrong?Whodecideswhichtraitsarenormal&whichconstituteadisabilityordisorder(decidingproperindications)?
B. Dowehaveenoughknowledgetomaketherightdecisions?Areweabletocontrolgenetherapy?Aretheresituations,whengenetherapyisethicallymoreacceptable?Whatarethecostsforthistypeoftherapyandwhoispayingforit?Willthehighcostsofgenetherapymakeitavailableonlytothewealthy?
Couldthewidespreaduseofgenetherapymakesocietylessacceptingofpeoplewhoaredifferent?Whatisthesocioeconomicimpactofgenetherapyinoursociety?
D. Shouldpeoplebeallowedtousegenetherapytoenhancebasichumantraitssuchasheight,intelligence(IQ),orathleticability(socalledgeneticenhancement)?Whatisthepotentialimpactofgermlinegenetransferonfuturegenerations?
Whatarethemajorconcernswithgermlinegeneediting?
A. Someoftheconcernsraisedaboutsomaticgenetransferarerelatedtothepossibilitythatitcouldinadvertentlyleadtogermlinegenetransfer.Germlinegenetransferatthegamete and zygotestageshavesignificantrisks.
Beyondthemedicalriskstothepotentialchild,anumberoflong-standingethicalconcernsexistregardingthepossiblepracticeofgermlinegenetransferinbothhuman and nonhumancases.
Concernsinvolveissuesrangingfromtheautonomyoffutureindividualstodistributivejustice,fairness, and theapplicationofthesetechnologiesto"enhancement".Concernsrelatedtoeugenicsandsocialjusticeandequalaccesstotechnologies.
D. Unequalaccessandculturaldifferencesaffectinguptakecouldcreatelargedifferencesintherelativeincidenceofagivenconditionbyregion,ethnicgroup,orsocioeconomicstatus.
Which of the following statements aboutsomatic cell gene therapy (SCGT) are correct?
A. In somatic cell gene therapy (SCGT), the therapeutic genes are transferred into any cell other than a gamete, germ cell, gametocyte, or undifferentiated stem cell.
B. Any such modifications affect the individual patient only, and are not inherited by offspring.
C. Somatic gene therapy represents mainstream basic and clinical research, in which therapeutic DNA (either integrated in the genome or as an external episome or plasmid) is used to treat disease.
D. Most focus on severe genetic disorders, including immunodeficiencies, hemophilia, thalassemia, and cystic fibrosis. Such single gene disorders are good candidates for somatic cell therapy.
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