Mutations

• Mutation


  A change in an organism's genetic code, alternatively called variation
• Mutations


  • Can happen as an error in DNA replication or an organism's exposure to a mutagen (a chemical or physical factor that can kickstart changes in DNA; ex. UV radiation, the chemical in tobacco products, etc.)
  • Some are inherited as they can be passed down from parent to offspring (ex. hemophilia)
• Somatic Mutation


  Occurs after conception, do not get passed on genetically, occurs anywhere in the body except for egg and sperm cells (ex. cancer)
• De Novo Mutation


  Occurs in an organism's egg or sperm cells, can be passed on to all of its offspring's cells
• Substitution


  One nucleotide is substituted for a different one
• Missense Mutation


  Creates a different protein that might not work as intended (ex. sickle cell anemia)
• Nonsense Mutation


  Can stop production, resulting in a fragment rather than a protein (ex. cystic fibrosis)
• Silent Mutation


  Creates the same protein with different genetic codes; affects when and how proteins are made
• Deletion


  Nucleotides get deleted
• Insertion


  Extra nucleotides get inserted
• Frameshift Mutation


  The entire protein-building process is thrown off (since genetic codes are read by threes)
• Chromosomal Mutation


  Mutation of chromosomes
• Ways Genetic Mutation Can Happen

  • Disruption in Chromosomal Structure
  • Disruption in Chromosome Number
• Deletion


  A part of a chromosome gets deleted and its height increases
• Duplication


  A part of a chromosome gets duplicated and its length increases
• Inversion


  Sections of DNA are flipped or reversed within the chromosome
• Insertion


  A segment gets inserted into another chromosome
• Translocation


  A segment from each chromosome gets interexchanged
• Chromosomal Abberation


  Structure of a chromosome gets altered and disrupted
• Aneuploidy


  The presence of an abnormal number of chromosomes in a cell
• Genetic Disorders


  Disorders caused by defective genes inherited from parents
• Hemophilia


  • Rare genetic disorder where blood does not clot properly due to insufficient clotting factors
• Symptoms of Hemophilia


  • Anemia - due to easy breakdown of sickle cells, leading to fatigue
  • Pain Crises - intense pain caused by blocked blood flow in various body parts
  • Swelling of Hands and Feet - resulting from blocked circulation
  • Frequent Infections - due to spleen damage
  • Delayed Growth or Puberty
  • Vision Problems
• Causes of Hemophilia


  Inherited from parents with a defective gene
• Cancer


  A group of diseases where abnormal cells grow uncontrollably and spread to other part of the body
• Symptoms of Cancer


  • Persistent Cough - with thick mucus
  • Wheezing
  • Exercise Intolerance
  • Recurrent Lung Infections
  • Digestive Issues - foul-smelling stools, poor weight gain, and intestinal blockage
• Causes of Cancer


  Various genetic and environmental factors
• Treatment for Cancer


  Depends on cancer type and stage
• Sickle Cell Anemia


  • An inherited blood disorder where red blood cells become sickle-shaped, causing blockages and damage
• Symptoms of Sickle Cell Anemia

  • Anemia - shortage of red blood cells due to rapid breakdown
  • Pain Crises - extreme pain from blocked blood flow
  • Swelling of Hands and Feet
  • Frequent Infections
  • Delayed Growth or Puberty
  • Vision Problems
• Causes of Sickle Cell Anemia

  Defective gene affecting mucus and secretions
• Treatment for Sickle Cell Anemia

  Managing symptoms and preventing complications
• Cystic Fibrosis


  • An inherited disorder damaging lungs, digestive system, and other organs due to thickened secretions
• Symptoms of Cystic Fibrosis

  • Respiratory Signs - cough, wheezing, and lung infections
  • Digestive Signs - poor weight gain, greasy stools, and intestinal blockage
• Causes of Cystic Fibrosis

  Defective gene affecting mucus and secretions
• Treatment for Cystic Fibrosis

  Daily care, improved screening, and treatments
• Duchenne Muscular Dystrophy (DMD)


  • A rapidly progressive genetic disorder primarily affecting boys
• Symptoms of Duchenne Muscular Dystrophy

  • Onset - between ages 2 and 4
  • Muscle Weakness - begins in legs and pelvis, progressing to other areas
  • Calf Muscle Hypertrophy - enlarged calf muscles
  • Difficulty Walking - worsens over time
  • Frequent Falls - waddling gate and toe walking
  • Fatigue
  • Cardiomyopathy - heart muscle weakness
  • Breathing Difficulties
  • Cognitive Impairment - learning difference
• Causes of Duchenne Muscular Dystrophy

  • Mutation in the DMD gene (X-linked recessive inheritance)
  • Lack of the protein dystrophin, leading to muscle fiber breakdown
• Treatment for Duchenne Muscular Dystrophy


  • No cure, but management focuses on symptom relief and improving quality of life
  • Medications (ex. corticosteroids) and therapies (physical and occupational)