wk 14-genetic testing

• Genetic disorders


  Inherited conditions
• Types of genetic disorders

  • Single gene inheritance
  • Multifactorial inheritance
  • Chromosome abnormalities
  • Mitochondrial inheritance
• Single-gene (monogenic)


  Conditions that occur from a single gene mutation
• Complex (multifactorial)


  Disorders that stem from a combination of gene mutations and other factors
• Chromosomal


  Type of genetic disorder that affects the structures that hold the genes/DNA within each cell (chromosomes)
• Chromosomal disorders


  • Down syndrome (Trisomy 21)
• In healthcare we are interested in the 0.1% variation in our genome because it tells us what
• What the 0.1% variation in our genomes can tell us

  • Whether someone will develop a condition
  • Whether someone is more susceptible to a condition
  • Whether someone will react differently to a drug
• Cancer is the most common disease of the genome
• Inborn errors of Metabolism (IEM)

  Inherited metabolic disorders due to mutations in the genes (DNA) on the chromosomes
• Modes of Inheritance


  Autosomal recessive, autosomal dominant, and X-linked recessive are forms of Mendelian inheritance
• Humans have 23 pairs of chromosomes
• For each pair of chromosomes, one is inherited from the mother and one from the father
• One pair is the sex chromosomes; females have two X chromosomes, males have one X and one Y chromosome
• The non-sex chromosomes are called autosomes
• Genetic family history


  Drawing a genetic family history of an individual and their close family members to identify patterns that could indicate an inherited condition
• Genetic Counselling


  Helping patients understand the risks and benefits of genetic testing, the potential results and what they mean, how family members may be affected, the risk of passing on a health condition to children, and options if they have a child with an inherited health condition
• Forms of genetic testing

  • Diagnostic testing
  • Carrier testing
  • Predictive testing
• Genetic disorders


  Inherited disorders
• Diagnostic testing


  Identifying current disease states, including prenatal and newborn screening
• Carrier testing


  Determining whether an individual carries a certain genetic trait
• Predictive testing


  Used to determine whether a person has a genetic mutation that will lead to a late onset disorder
• Disorders for which genetic tests are available

  • Huntington's disease
  • Cystic fibrosis
  • Breast cancer
  • Down's syndrome
  • Sickle cell anaemia
  • Phenylketonuria
• Types of genetic disorders

  • Single gene inheritance
  • Multifactorial inheritance
  • Chromosome abnormalities
  • Mitochondrial inheritance
• Carrier testing


  Blood test that shows whether you or your partner carry a mutation linked to genetic disorders
• Prenatal screening


  Testing, usually involving blood testing from a pregnant person, that tells them how likely it is that a fetus could have a common chromosome condition
• Single-gene (monogenic)


  Conditions that occur from a single gene mutation
• Prenatal diagnostic testing


  Testing that uses a sample of fluid from the uterus (amniocentesis) to find out whether the developing fetus faces a higher risk for certain genetic disorders
• Newborn screening


  Test that uses a sample of a newborn baby's blood and is performed on all babies, detecting genetic disorders early in life to help the child receive timely care if needed
• Chromosomal tests (cytogenetics)


  Microscopic examination of chromosomes from cells in blood, amniotic fluid or fetal tissue to detect chromosomal changes
• Complex (multifactorial)


  Disorders that stem from a combination of gene mutations and other factors
• Until recent years it was only possible to detect large alterations on a chromosome involving many genes, but new techniques are making it much smaller defects</b>
• Tests for disorders involving a single gene

  In the past, these have been largely indirect, involving what the gene produces (protein) or another substance affected by it, rather than the gene itself
• Antibiotic resistance is due to changes in bacterial DNA that allow bacteria to adapt and survive the antibiotics designed to kill them
• Conditions with a genetic cause

  • Cystic fibrosis
  • Huntington disease
  • Sickle cell anaemia
• Chromosomal

  Type of genetic disorder that affects the structures that hold the genes/DNA within each cell (chromosomes)
• Autonomy


  The ability of a person to make considered judgments and decisions that lead to acts that foster self-reliance or independence
• Nonmaleficence


  The obligation not to harm others
• Chromosomal disorders

  • Down syndrome (Trisomy 21)
• Beneficence


  The obligation to help others further their important and legitimate interests when we can do so at minimal risk to ourselves