The Genetic Revolution

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The Genetic Revolution

• Nasim Monfared
• Genetic Counsellor
• Childrens Hospital of
• Eastern Ontario
• November 12, 2012

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• Today
• History
• Genetics in the news
• General genetics
• Genetic testing
• Ethical issues
• Career choices?

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Historical

• Vampires thought to have a genetic condition
  called porphyria
• Porphyria
• Skin changes
• Teeth reddish tinge
• Pain
• Need to avoid sun

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Historical

• Witches of Salem thought to have a genetic
  condition called Huntingtons disease

• Huntingtons disease
• Uncontrolled movement
• Personality and intellect changes

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Historical

• The Elephant Man had a genetic condition called
  Proteus syndrome

• Proteus syndrome
• Atypical growth of bones, skin, and head

Joseph Merrick
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Historical

• Greek mythology cyclops, mermaids, etc.

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Historical

• Hemophilia in the Royal Family

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Genetics in the Media
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Why do I need to know about this stuff?!

• We all inherit genetic info from our parents
• We all pass on genetic info to our kids
• We are all at risk for something

BUT. Genetic does not always mean inherited
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General Genetics
Cells do the work of the body
Each cell contains a set of chromosomes inside
the nucleus
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Humans typically have 23 pairs of chromosomes in
each cell of the body
We get one copy of each chromosome from our
parents
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Which species has the most number of chromosomes?

• Maple tree
• Dog
• Butterfly
• Chimpanzee

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Chromosomes and Genes

• A chromosome is made up of DNA
• DNA makes up our genes
• How do we maintain the right number of cells?

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Mitosis

• Mitosis
• http//www.youtube.com/watch?vzGVBAHAsjJM

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Genomics

• What is Genomics?
• What is a gene?
• Genes are like recipes that tell the body how to
  grow and develop
• We all have about
• 25 000 genes in total!

Genes digest your food
Genes make your muscles move
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The Role of Genes

• It is important that our genes work properly
• Mutation A change in a gene that causes it not
  to work properly

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Effects of Mutations
Genes digest your food
Genes make your muscles move
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Cystic Fibrosis
1 in 25 Caucasians are carriers
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• Sickle cell disease

• Sickle-shaped hemoglobin
• Anemia
• Recurrent infection
• Splenomegaly
• Painful crises
• Autosomal recessive inheritance
• Mutations in beta-globin gene
• Heterozygote fitness

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Achondroplasia (Dwarfism)
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achondroplasia

• Short stature
• Macrocephaly
• Frontal bossing
• Midface hypoplasia
• Normal intelligence and lifespan
• Autosomal dominant inheritance
• Mutations in FGFR3 gene
• Father diastrophic dysplasia

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Marfan syndrome

• Tall, lanky stature
• Arachnodactyly
• Aortic dilatation
• Joint hypermobility
• Myopia
• Mutations in FBN1 gene

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Muscular Dystrophy

• Continual loss of muscle
• Affects boys
• Will need wheelchair around age 10

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Not all gene changes are bad!

• Gene changes make us all different

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Genetic Variation
DNA is 98 identical to human DNA
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Effects of Gene Changes
Tongue rolling
Is this trait thought to be dominant or recessive?
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Earlobe Attachment
Free Attached

• Ear lobes are either free (detached) or
  attached.

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Other Genetic Traits

• Mid-digit Hair
• Cheek Dimples
• Bushy eyebrows
• Freckles
• Widows peak

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Other Genetic Traits

• Red Hair
• Straight Hair
• Square Face
• Short eyelashes
• Long fingers

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Genetic Testing

• Genetic testing is available for over 1000
  conditions
• Reasons for genetic testing
• Diagnosis
• Carrier screening
• Newborn screening
• Presymptomatic testing
• Preimplantation genetic diagnosis
• Testing a pregnancy
• Forensics

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Looking at chromosomes

• Also called a karyotype
• Looks at NUMBER and SHAPE of chromosome
• Will often detect GENETIC conditions that are not
  INHERITED

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Chromosome analysis - FISH
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Down Syndrome (trisomy 21)
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Features of Down Syndrome
Eye folds
No eye folds
Hand crease
Weak muscles, tongue sticking out
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Gene Analysis

• DNA is isolated from blood
• Chemicals and electricity are used to look for
  changes in a specific gene

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• GENOMIC MICROARRAY

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• DYE SWAP AND ANALYSIS

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Genome Sequencing

• Why would someone want their genome sequenced?

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Sanger sequencing

• DNA sequencing - the Sanger method
• How the sequence of bases in a DNA molecule is
  determined.
• http//www.dnalc.org/view/15479-Sanger-method-of-D
  NA-sequencing-3D-animation-with-narration.html

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Preimplantation Genetic Diagnosis (PGD)

• Type of testing that can be used with in vitro
  fertilization
• In vitro fertilization Creating an embryo
  outside of the womans body and then put it back
  into her uterus

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Preimplantation Genetic Diagnosis (PGD)

• Removal of one cell from an embryo
• Test the cell for a genetic condition
• Pick the embryo that does not have the condition

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Direct-to-consumer genetic testing

• CF
• BRCA genes
• Tay Sachs
• Thalassemias
• Heart disease
• Diabetes
• Alzheimers disease

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• http//www.youtube.com/watch?v8JTw2RpDo9ofeature
  related

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Stem cells in use

• Are There Different Types of Stem Cells?
• Somatic Stem Cell Therapy Using a Bone Marrow
  Transplant to Cure Leukemia
• Peripheral Blood Stem Cells
• Umbilical Cord Blood Stem Cells

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Ethical Issues
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Ethics and Genetics

• Who should know your personal genetic
  information?
• Your boss? An insurance company? Your family?
• Who owns and controls genetic information?
• How does your genetic information affect the way
  you think about yourself? The way your friends
  think about you?
• How does genetic testing affect different
  cultures?

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Ethics and Genetics

• Should we test for conditions if there is no
  treatment?
• Should parents be allowed to test their kids for
  conditions that start when the kid is an adult?
• How do we make sure that your doctors know enough
  about genetics?
• Therapies and Prevention- How are we already
  putting our new knowledge of the human
  genome into practice?
• http//www.insidedna.org.uk/content/?tagtherapy

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Ethics Cases
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Case Mr. F and George

• Mr. F is 42 his son George is 21
• They come for genetic counselling for advice.
• George wants to be tested for Huntington disease.
• This is a progressive, fatal inherited brain
  condition where individuals develop symptoms in
  their 30s, 40s and 50s.
• There is a 50 chance that Mr. F has inherited
  the gene for Huntington disease and, if so, a 50
  chance he has passed it along to his son George.

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Case Mr. F and George

• Mr. F has a 50 chance of getting the gene for
  Huntington disease from his dad
• If Mr. F has it, George is at 50 risk of also
  having it.

Mom
Dad
?
Mr. F
?
George
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Scenario Mr. F and George

• Mr. F does not show symptoms and he does not want
  to be tested.
• He prefers to live his life and make decisions
  without knowing if he has the condition.
• George wants to know if he has inherited the
  condition so he can plan for the future.

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Case Mr. F and George

• If George gets tested and is found to carry the
  gene, his father, Mr. F, must also carry the
  gene.
• The two men agree that, since they talk about
  everything, it would be impossible for George to
  keep his test result a secret from his father.

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The Right To Know

• Does George have a right to know whether or not
  he carries a disease gene even if it interferes
  with his father's wish not to know his genetic
  status?

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The Right Not To Know

• Does Mr. F have a right not to know?

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Other ethical issues

• Testing children
• Sex-selection
• Abortion
• Adoption

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Ethics and Genetics

• The amount of information we have learned about
  genetics over the past 20 years has raised many
  ethical issues
• Part of the Human Genome Project was to explore
  these issues
• We need to consider the impact of genetic
  information on you, your family, and your
  community

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Careers in Genetics

• Geneticist Clinical, Laboratory, Research
• Genetic Counsellor
• Bioinformatician
• Biostatistician/Epidemiologist
• Biomedical Engineer
• Forensic investigator
• Cytogenetic technologist
• Molecular technologist
• Ethicist
• Microbiologist
• Research Scientist (Biotechnology,
  pharmaceuticals, etc)

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Where to get more information

• Online (not every website gives true information)
• The Hospital for Sick Children
• http//www.sickkids.ca/childphysiology/cpwp/Geneti
  cs/geneticsintro.htm
• Canadian Association of Genetic Counsellors
• https//cagc-accg.ca/component/option,com_frontpag
  e/Itemid,1/
• Welcome Trust Foundation
• http//www.wellcome.ac.uk/
• American Society of Human Genetics
• www.ashg.org/
• Nasim Monfared 613-737-7600 x 1374
  nmonfared_at_cheo.on.ca

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Thank you!