Human Genetic engineering

RAB 8 Barisal

Introduction:

Human genetic engineering is the alteration of an individual’s genotype with the aim of choosing the phenotype of a newborn or changing the existing phenotype of a child or adult.

It holds the promise of curing genetic diseases like cystic fibrosis. Gene therapy has been successfully used to treat multiple diseases, including X-linked SCID, chronic lymphocytic leukemia (CLL),[  and Parkinson’s disease. In 2012, Glybera became the first gene therapy treatment to be approved for clinical use in either Europe or the United States after its endorsement by the European Commission.

It is speculated that genetic engineering could be used to change physical appearance, metabolism, and even improve mental faculties like memory and intelligence, although for now these uses are limited to science fiction.

History

Gene therapy trials on humans began in 2004 on patients with severe combined immunodeficiency (SCID). In 2000, the first gene therapy “success” resulted in SCID patients with a functional immune system. These trials were stopped when it was discovered that two of ten patients in one trial had developed leukemia resulting from the insertion of the gene-carrying retrovirus near an oncogene. In 2007, four of the ten patients had developed leukemia.[7] Work is now focusing on correcting the gene without triggering an oncogene. Since 1999, gene therapy has restored the immune systems of at least 17 children with two forms (ADA-SCID and X-SCID) of the disorder

Human genetic engineering is already being used on a small scale to allow infertile women with genetic defects in their mitochondria to have .

children. Healthy human eggs from a second mother are used. The first mother thus contributes the 23 chromosomes of the nuclear genome, which contain the majority of the child’s genetic information, while the second mother contributes the mitochondrial genome, which contains 37 genes. The child produced this way has genetic information from two mothers and one father. The changes made are germline changes and will likely be passed down from generation to generation, and, thus, are a permanent change to the human genome

Other forms of human genetic engineering are still theoretical. Recombinant DNA research is usually performed to study gene expression and various human diseases. This includes the creation of transgenic animals, such as mice.

Applications

Genetic engineering can be broken down into two applications, somatic and germline. Both processes involve changing the genes in a cell through the use of a vector carrying the gene of interest. The new gene may be integrated into the cell’s genetic material through recombination, or may remain separate from the genome, such as in the form of a plasmid. If integrated into the genome, it may recombine at a random location or at a specific location (site-specific recombination) depending on the technology used.

Somatic cell therapy

As the name suggests, somatic cell therapy alters the genome of somatic cells. This process targets specific organs and tissues in a person. The aim of this technique is to correct a mutation or provide a new function

in human cells. If successful, somatic cell therapy has the potential to treat genetic disorders with few therapeutic options. This process does not affect the genetics of gametic cells within the same body. Any genetic modifications are restricted to a patient individually and cannot be passed on to their offspring.

Several somatic cell gene transfer experiments are currently in clinical trials with varied success. Over 600 clinical trials utilizing somatic cell therapy are underway in the United States. Most of these trials focus on treating severe genetic disorders, including immunodeficiencies, haemophilia, thalassaemia, and cystic fibrosis. These disorders are good candidates for somatic cell therapy because they are caused by single gene defects. While somatic cell therapy is promising for treatment, a complete correction of a genetic disorder or the replacement of multiple genes in somatic cells is not yet possible. Only a few of the many clinical tries are in the advanced stages.

Germline cell therapy

Germline cell therapy alters the genome of germinal cells. Specifically, it targets eggs, sperm, and very early embryos. Genetic changes made to germline cells affect every cell in the resulting individual’s body and can also be passed on to their offspring. The practice of germline cell therapy is currently banned in several countries, but has not been banned in the US.

Theoretically, germline cell therapy could treat or cure individuals who are predisposed to certain genetic disorders before birth. This process has not been attempted on humans, but has been applied to some plants and various animal species.. Several problems have arisen with this

method, including only partial or multiple insertions of the desired gene, inaccurate placing of the desired gene in to the genome, and interference with other critical genes in the genome. While most defects are detectable in embryos, it is likely that some would be overlooked. Animal studies have shown that gene transformations involving the early embryo can be more effective than somatic cell transformations. However, attempts of germline cell transfer on human embryos will not be attempted unless the inefficient transformation that occurs during germline cell therapy is overcome.

Current studies

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Regulations

Policies on genetic modification tend to fall in the realm of general guidelines about human-involved biomedical research. Universal restrictions and documents have been made by international organizations to set a general standard on the issue of involving humans directly in research.[citation needed]

One key regulation comes from the Declaration of Helsinki (Ethical Principles for Medical Research Involving Human Subjects), last amended by at the World Medical Association’s General Assembly in 2008.[17] This document focuses on the principles physicians and researchers must consider when involving humans as the research subject. Additionally, the Statement on Gene Therapy Research initiated by the Human Genome Organization in 2001 also provides a legal baseline for all countries. HUGO’s document reiterates the organization’s common principles researchers must follow when conducting human genetic research including the recognition of human freedom and adherence to human rights, and the statement also declares recommendations for somatic gene therapy including a call for researchers and governments to attend to public concerns about the pros, cons and ethical concerns about the research.[

United States

No federal legislation specifically lays out protocol and restrictions about either germline or somatic human genetic engineering. Instead, this subject is governed by overlapping regulations from local and federal agencies. Included agencies, from the Department of Health and Human Services, are the Food and Drug Administration and the Recombinant DNA Advisory Committee of the National Institutes of Health. Additionally, researchers who wish to receive federal funds when conducting research about an investigational new drug application, which is commonly the case for somatic human genetic engineering, are required to obey international and federal guidelines dealing with the protection of human test subjects

The National Institutes of Health (NIH) mainly serves as the gene therapy regulator for federally funded research institutions and projects. Privately funded human genetic research can only be recommended to voluntarily follow their regulations. NIH provides funding for lab research that develops or enhances devices utilized in human genetic engineering and to evaluate the ethics and quality of science present in current research labs. The NIH maintains a mandatory registry of human genetic engineering research protocols from all federally funded projects. An advisory committee to the NIH published a set of guidelines on the manipulation of genes. The document for the NIH guidelines discusses safety considerations for the lab as well as for any human patient test subject. A wide range of various experimental types which involve any type of gene transfer or alteration are discussed. Several sections specifically pertain to human genetic engineering including Section III-C-1. This section states the review process researches must undergo and the aspects that are considered when attempting to be approved to begin clinical research involving human genetic transfer into a patient. This document is an important tool required for scientists to follow in order to further scientific progress in the field of somatic cell therapy.

The United States Food and Drug Administration (FDA) regulates the quality and safety of gene therapy products and supervises how these products are implicated clinically. Therapeutic alteration of the human genome falls under the same regulatory requirements as any other medical treatment. Research involving human subjects, such as clinical trials, must be reviewed and approved by the FDA and an Institutional Review Board.

Ethics

The potential for new technologies and genetic modifications brings along many ethical and moral concerns. Some of these concerns include the belief that every fetus has an inherent right to remain genetically unmodified, the belief that parents hold the rights to modify their unborn offspring, and the belief that every child has the right to be born free from preventable diseases.[24]

The ability to alter the course of human development ranks among the most significant changes in modern science to date. The sex and eye color of a child can be planned in advance. A test for the presence or absence of certain genes can be performed, and if the results indicate an embryo that will not reach “normalcy”, that embryo can be aborted. The potential for curing diseases and enhancing human capabilities is immense. Stems cells that are capable of becoming almost any cell in the body can be obtained and cloned. The question that must be asked is: Even if we can do such things, should we do such things? What benefits could these technologies have for the human population?

Molecular biologist Lee M. Silver has posited that unlike Aldous Huxley’s Brave New World, where a totalitarian government employs eugenics to control the genetic makeup within society, the use of gene therapy to design children will be spread through what he calls “free market eugenics” (Silver 315). Wealthy families will opt to design their child with genetic advantages because other families are doing so. Silver believes this use of germline gene therapy will mean wealthy families pass down enhanced traits to their children, potentially disadvantaging poorer families that cannot afford the technology. (Silver 313) However, according to James Hughes, it is possible that Medicaid will cover the costs for fertility services, eliminating the inequality

Pros

The science of genomics is able to identifying which genes cause specific diseases. Through genetic testing, it has become much easier to make a diagnosis for many genetic conditions. This testing supplies the ability to test pre-symptomatic individuals, at-risk individuals, and carriers to determine whether they will develop a specific condition. It is particularly useful to people who intend to have children, and want to ensure they will not pass their genetic condition to their offspring. Current advances include preimplantation genetic diagnosis, which allows for embryos to be created in vitro, and only those embryos that are not affected by a specific genetic disorder will be implanted in the woman’s uterus.

Another beneficial aspect of genetic engineering is the potential to cure numerous genetic diseases. The majority of genetic disorders are cause by single point mutations in the DNA. By somatic cell therapy, these diseases can be easily cured. Additionally, the implementation of germline cell therapy can not only cure many other genetic diseases, but can also prevent the passing of the disease to the next generation.

Genetic engineering also allows the potential for human enhancements. Humans value intelligence, beauty, strength, endurance, and certain personality characteristics and behavioral tendencies. If these traits were found to be due to a genetic component, humans could be improved to obtain those traits. Many people try to improve themselves already through diet, exercise, education, cosmetics, and plastic surgery. Humans try to do these things for themselves and parents try to provide these things for their children. Exercising to improve strength, dexterity, and fitness is a worthwhile goal. Pursuing education to increase mental

capabilities is considered a praiseworthy act. Accomplishing these goals through genetics could be more efficient and completely worthwhile.[27]

Cons

The techniques for genetic engineering have not yet been perfected. Problems occurring during the transformation of new genes could cause multiple or incomplete insertions or insertions into the wrong locations. Until the transformation process is perfected, mistakes during this phase have the potential to cause more harm than good.

Since genetic manipulations may one day be able to not only affect disease resistance, but could also affect appearance, intelligence, and personality, it is suggested[by whom?] that human genetic engineering could lead to genetic discrimination. Even though DNA is only one aspect of development, those who have undergone some form of genetic engineering may be enhanced to have qualities that are desired by the species. Optimization of human traits by genetic modifications may be considered a form of eugenics, and could lead to social issues between humans that have been “engineered” and humans that have not.

Concerns have also been raised over gene doping, which is defined by the World Anti-Doping Agency as “the non-therapeutic use of cells, genes, genetic elements, or of the modulation of gene expression, having the capacity to improve athletic performance”. Genetic enhancements could improve athletic performance by increasing muscle growth, blood production, endurance, oxygen dispersal or pain perception. This process has already been implemented in animal models, leading to mice with increased muscle mass and stamina. This procedure has no yet been

perfected in large animal models, making it very risky for athletes to use these methods.

 Conclusion:(Genetic neglect)

Future genetic intervention technologies will allow parents the ability to provide genetic inputs for their children. Hammond (2010) compared the differences between conventional neglect and genetic neglect. Conventional neglect being defined as providing bad environmental inputs, such as a parent failing to feed her child or shaking her child. Genetic neglect being defined as failing to prevent genetic disorders, such as hereditary spastic paraplegia, when a parent has the ability to do so. Hammond stated that parents who could provide adequate genetic input for their children, but fails to do so, is guilty of genetic neglect, which she argued is just as severe as conventional neglect and that we are “morally obliged to use some genetic interventions to prevent some serious genetic disabilities and diseases

References

  1. ^ Singer, Peter; Kuhese, Helga. Bioethics: An Anthology.
  2. ^ Fischer, A.; Hacein-Bey-Abina, S.; Cavazzana-Calvo, M. (2010). “20 years of gene therapy for SCID”. Nature Immunology 11 (6): 457–460. doi:10.1038/ni0610-457. PMID 20485269. edit
  3. ^ Ledford, H. (2011). “Cell therapy fights leukaemia”. Nature. doi:10.1038/news.2011.472. edit
  4. disease: A double-blind, sham-surgery controlled, randomised trial”. The Lancet Neurology 10 (4): 309–319. doi:10.1016/S1474-4422(11)70039-4. PMID 21419704. edit
  5. ^ Gallagher, James. (2 November 2012) BBC News – Gene therapy: Glybera approved by European Commission. Bbc.co.uk. Retrieved on 15 December 2012.
  6. ^ Richards, Sabrina. “Gene Therapy Arrives in Europe”. The Scientist. Retrieved 16 November 2012.
  7. ^ Press release from the European Society of Gene Therapy
  8. ^ a b c “Genetically altered babies born”. BBC News. 2001-05-04. Retrieved 2008-04-26.
  9. ^ Fulvio Mavilio, Giuliana Ferrari. Genetic modification of somatic stem cells: The progress, problems and prospects of a new therapeutic technology. EMBO Rep. 2008 July; 9(S1): S64–S69. doi: 10.1038/embor.2008.81. PMCID: PMC3327547.
  10. ^ Hanna, K., 2006, Germline Gene Transfer, National Human Genome Research Institute,
  11. ^ 2013, Human Cloning and Genetic Modification, Association of Reproductive Health Officials,
  12. ^ 2013, Gene Therapy, American Medical Association,
  13. ^ Retroviral Integrations in Gene Therapy Trials
  14. ^ “New leukemia treatment exceeds ‘wildest expectations'”. MSNBC. 2011-10-08.
  15. ^ “Chimeric Antigen Receptor–Modified T Cells in Chronic Lymphoid Leukemia”. New England Journal of Medicine. 2011-09-25.
  16. ^ Zinc-finger Nuclease Editing of Human cxcr4 Promotes HIV-1 CD4+ T Cell Resistance and Enrichment
  17. for Medical Research Involving Human Subjects). October 2008.<http://www.wma.net/en/30publications/10policies/b3/17c.pdf>]
  18. ^ Human Genome Organization. HUGO Ethics Committee. Statement on Gene Therapy Research. April 2001.
  19. ^ Isasi, Nguyen, Knoppers. National Regulatory Frameworks Regarding Human Genetic Modification Technologies (Somatic and Germline Modification). Genetics & Public Policy Center. October 2006 >
  20. ^ National Institutes of Health. NIH Guidelines for Research Involving Recombinant or Synthetic Nucleic Acid Molecules. Revised March 2013.
  21. ^ U.S. Department of Health & Human Services. The National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research. The Belmont Report: Ethical Principles and Guidelines for the Protection of Human Subjects of Research. 18 April 1979.
  22. ^ U.S. Food and Drug Administration. Application of Current Statutory Authorities to Human Somatic Cell Therapy Products and Gene Therapy Products. Federal Register. Vol. 58. No. 197. 14 October 1993.
  23. ^ U.S. Department of Health and Human Services. Food and Drug Administration. Center for Biologics Evaluation and Research. Guidance for Industry: Guidance for Human Somatic Cell Therapy and Gene Therapy. March 1998.
  24. ^ Buchanan, A., Powell, R. (2011). Breaking Evolution’s Chains: The Prospect of Deliberate Genetic Modification in Humans. J Med Philos, 36(1): 6-27 first published online January 12, 2011doi:10.1093/jmp/jhq057]
  25. ^ Designer Babies: A Right to Choose?

^ Lewitt, P. A.; Rezai, A. R.; Leehey, M. A.; Ojemann, S. G.; Flaherty, A. W.; Eskandar, E. N.; Kostyk, S. K.; Thomas, K. et al. (2011). “AAV2-GAD gene therapy for advanced Parkinson’s

^ [World Medical Association. 59th General Assembly. World Medical Association Declaration of Helsinki (Ethical Principles.

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