gene

• Gene Therapy


  A therapeutic strategy using genetic engineering techniques to cure diseases or disorders caused by a genetic problem
• Gene Therapy allows the correction of disease-causing mutations to prevent the onset of diseases
• Gene Editing


  A more precise technique than genetic engineering that targets a specific DNA sequence

  
• Genes

  The blueprint of life that carry the information responsible for an individual's traits
• DNA (Deoxyribonucleic Acid)

  The genetic material in our body cells that contains the instructions that direct cells to make proteins

  
• Genome


  The complete set of DNA or genes in a cell or organism

  
• Human Genome


  • Consists of DNA packed together in 46 chromosomes
  • Each chromosome contains 2 chromatids with sequences of DNA

  
• Genetic Disorders


  Diseases caused by a mutation or change in the DNA sequence of an individual
• Types of Genetic Disorders

  • Single-Gene Disorders
  • Chromosomal Disorders
  • Multifactorial Inheritance
• Single-Gene Disorders

  • Sickle Cell Anemia
  • Cystic Fibrosis
  • Tay-Sachs Disease
  • Duchenne Muscular Dystrophy
  • Hemophilia
  • Color Blindness
• Gene Therapy Methods

  • Randomly inserting a normal gene into the genome
  • Replacing the abnormal gene with the normal gene
  • Repairing the abnormal gene
  • Altering regulation of a particular gene
• Vectors

  Vehicles or agents used to introduce or insert genes into a cell
• Gene Therapy Vectors


  • Retrovirus
  • Adenovirus
  • Adeno-associated virus
  • Cis and trans-acting elements
  • Herpes simplex virus
• Non-viral Gene Therapy Method


  Injection of naked DNA
• Gene therapy


  A method of treating or preventing diseases by replacing, repairing, or turning on or off genes of a patient's cells
• Gene therapy

  • Helps treat genetic disorders that occur due to mutations that alter or inhibit protein functions
  • Focuses on correcting defective genes by: 1) Randomly inserting a normal gene into the genome, 2) Replacing the abnormal gene with the normal gene, 3) Repairing the abnormal gene, 4) Altering regulation of a particular gene
• Gene therapy methods


  1. Using vectors (Viral Methods) or without vectors (Non-viral Methods) to move DNA or genes to one cell

  2. Vectors are vehicles or agents used to introduce or insert genes into the cell
• Gene therapy vectors

  • Retrovirus
  • Adenovirus
  • Adeno-associated virus
  • Cis and trans-acting elements
  • Herpes simplex virus
• Non-viral method in gene therapy

  • Injection of naked DNA
  • Can produce DNA on a large scale
• Transgenic or genetically modified

  Cells, tissues, and organisms where gene therapy is employed
• Types of Gene Therapy

  • Somatic Gene Therapy
  • Reproductive Gene Therapy or Germ-line Cell Therapy
• Somatic Gene Therapy


  • The genes are introduced to cells in the target organ (non-sex cells) to produce enzymes needed by the body to function well without altering the organism's genetic make-up
  • The changes caused are not transferred to the offspring
• Reproductive Gene Therapy or Germ-line Cell Therapy

  • Involves introducing corrective genes to sex cells (sperm cells, egg cells) or 4-day old zygotes
  • The process removes the abnormalities that the offspring may inherit
• In gene therapy, the medical experts must correctly identify the genes responsible for the progression of the disease, the modified gene must reach the cell or target organ accurately, controlled, and effectively, and cells can reject modified genes because of the body's natural defense mechanism that causes most of gene therapy failures
• Two Approaches of Gene Therapy

  • Ex vivo - transfer of genes in cultured cells and will be reinjected to the body of the patient
  • In vivo - introduction of therapeutic gene into the vector injected directly to the body
• Non-viral vectors


  Depend on physical or chemical methods of delivering genetic material into a cell
• Viral vectors


  Built using a blueprint of a virus—not the actual virus itself. Scientists only use the parts of the blueprint of the virus that help with delivering genetic material
• Viruses provide an ideal model for delivering gene therapy to a host cell as they are very effective at entering a cell
• Benefits of Gene Therapy

  • Offers a cure for cancer, Parkinson's disease, AIDS, asthma, diabetes, heart diseases, and other hereditary diseases
  • Can replace defective cells
  • Has promising potential in the field of medicine and other related areas like agriculture
• Disadvantages of Gene Therapy

  • Modifying organisms means modifying their capabilities
  • Viral vectors could recover their ability to cause disease
  • Can damage the gene pool resulting in multigene disorder
  • High cost
  • Ethical issues
• Ethical Issues of Gene Therapy

  • How can good and bad uses of gene therapy be distinguished?
  • Who decides which traits are normal and which constitute a disability or disorder?
  • Will the high costs of gene therapy make it available only to the wealthy?
  • Could the widespread use of gene therapy make society less accepting of people who are different?
  • Should people be allowed to use gene therapy to enhance basic human traits such as height, intelligence, or athletic ability?
  • Is germline gene therapy ethical?
• Gene therapy has both positive and negative impacts on society, and understanding its potential benefits and risks and the awareness of its socio-scientific issues can help assess the usefulness of this technology