Genetic Disorders
What are genetic disorders?
• You are born with them – they are inherited.
• Some are common, others are very rare
• Examples:
– World’s tallest man: Robert Wadlow (8 foot, 11.1
inches tall, overactive pituitary gland)
– “Tree man”: Dede Koswara (Epidermodysplasia
Verruciformis, form of HPV)
– Elephant Man: Joseph Carey Merrick
World’s Tallest Man
• Robert Wadlow (8 foot, 11.1 inches tall)
Robert
and his
father
“Tree Man”
• Dede Koswara (Epidermodysplasia Verruciformis, form of HPV)
When 10 years old, and out playing in
the forest, he cut his knee… warts
appeared and continued to grow.
These warts smelled and eventually
became extreme. He lost his family
and his job.
His GENETIC condition is a rare immune
deficiency syndrome, similar to AIDS,
where his body’s immune system is
very weak, which allowed the virus
(warts) to grow out of control.
Elephant Man
• Joseph Carey Merrick (Proteus Syndrome)
Starting
at the
age of 2,
strange
tumors
began to
grow all
over his
body.
Definitions
• Disease
– Impairment of the normal state of living, often in
response to environmental factors or infective
agents.
• Malnutrition, industrial hazards, climate
• Worms, bacteria, viruses
• Disorder
– Disturbance in, or abnormal, physical or mental
condition
• Syndrome
– Group of symptoms that together are
characteristic of a specific disease or disorder.
Heredity
Karyotype
 A picture of the
chromosomes from a
human cell arranged
in pairs by size and
banding pattern
 First 22 pairs are
called autosomes
 Last pair are the sex
chromosomes
 XX female or
XY male
7
How do you do a Karyotype?
• Cells that are dividing are collected –
– Amniocentesis
• Needle inserted into the uterus to collect fluid
and fetal skin cells
• Sample is shipped off to a Cytogenetics
Lab
– At the lab, the chromosomes in the nucleus
of the cells are isolated, dyed (so they can
be seen), then a picture is taken.
– Cells are then counted, sorted and another
picture is taken.
Lab
You are going to make your own karyotype
from cells taken from a human with a
genetic disorder.
First, Cut out the template that has one of
the chromosome pairs already in size order
and glue into your notebook.
Then, match up the chromosomes based on
size and banding pattern and glue them to
the template.
You will have an extra chromosome – find
where it goes and glue it in.
Then begin answering the questions in your
lab.
Karyotype Notation
• In one line, you will know everything you
need to know about the karyotype.
• Contains
– Number of chromosomes in Karyotype
– Sex chromosomes
– Where extra (+) or missing (-)
chromosomes are
Karyotype Notation
• Normal
46, XX
• Female
46, XY
• Male
• Abnormal
• 45, XY, -8
• Missing 1
chromosomes, Male,
at #8
• 47, XY, +18
• Extra Chromosome,
Male, at #18
Presentations
• Be Respectful to your fellow peers
– Listen to those who are presenting
– Pay attention to the presenter
– When presenting, be loud enough for all to hear
– Be proud of your work
Down Syndrome
• Trisomy 21 (Full: All cells)
• Physical symptoms: Flat face, upward slanted
eyes, short neck, small hands/feet.
• Other symptoms: Hearing problems, intestinal
problems, heart disease, skeletal problems, eye
problems.
• Not inherited – typically happens when an older
woman has a child. Chromosomes don’t separate
and the child gets an extra one.
• High risk: 1 in 100 women (age 40+) have a child
with Down Syndrome
Patau Syndrome
• Trisomy 13 (Full: all cells involved, Mosaic: Some cells
have extra copies, Translocation: rearrangement of
genetic material between chromosome 13 and
another)
• Physical symptoms: Cleft lip or palate, polydactyl,
hernias, small eyes, small head,
• Other symptoms: Mental retardation, seizures, heart
disease and/or failure, deafness, vision problems.
• Typically not inherited – typically happens when
chromosomes don’t separate during the formation of
eggs and sperm (Called Non-disjunction).
Translocation may be inherited.
• Rare: 1 in 16,000 newborns. *More than 80% die in
the first year after birth.
Kleinfelter’s Syndrome
• XXY Condition (Full: all cells or Mosaic: some
cells.)
• Physical symptoms: Weak muscles, less facial hair,
larger breasts, tooth decay.
• Other symptoms: Reduced strength, language
delay, quiet and shy, infertile, intellectual
problems.
• Not inherited – typically happens when
chromosomes don’t separate during the
formation of eggs and sperm.
• High risk: 1 in 500
Hermaphrodite
• Organism that is fully male and fully female.
– Snails and slugs
• Intersex (preferred term for humans)
– Have both testicular and ovarian tissues (not fully both)
– 1 out of 2,000 children born
– 46, XX Ovaries inside, but have a “penis-like” external
genitalia
– 46, XY Testes normal, malformed or absent, and genitalia
normal, malformed or female in nature.
– 47, XXY or 47, XXX or 45, X0 Typical genitalia, no mixtures
Spina Bifida
• Myelomeninocele, Spina bifida occulta
– Most common forms
• Happens in 1 out of 800
births
• What is it?
– Birth defect
– Backbone/spine don’t close before birth
– Many times, there is a sac sticking out of the back.
• Normally, in the 1st
month of pregnancy,
the two sides of the
backbone join together
to cover the spinal
cord, nerves and
meninges.
Spina Bifida Babies
• Must handle carefully!
• Need surgery to repair spine.
• Typically present:
– Hydrocephalus
– Hip dislocation
– Weakness or paralysis of hips/legs/feet
– Lack of sensation
– Abnormal feet/legs
– Bladder problems
Spina Bifida Children and Adults
• Length of life typically
not effected.
• Many wear braces,
corrective shoes, and/or
are confined to a
wheelchair.
• Get many UTI’s
• Hydrocephalus
Causes of Spina Bifida
•
•
•
•
Don’t really know –
Could be low folic acid
Could be a virus
Could be inherited
Autism
• What is it?
– Neurodevelopment disorder
• Problems with social interactions and communication
–
–
–
–
Unresponsive
Withdrawn
Avoid eye contact
Can’t empathize (don’t understand feelings/expressions)
• Repetitive behaviors, or an avoidance of behaviors
– Rocking, spitting, mumbling
– Avoidance of water, rooms, colors
• Food textures
• Don’t do well with change – need structure
What causes Autism?
• Thought to be genes AND environment.
– DNA – hereditary
– Chemicals in the brain
• Natural interactions
• Foods eaten
• Environmental factors
How is Autism treated?
• There is no cure
• Educational interventions
– Extra help in learning modalities and techniques
• Behavioral interventions
– Training to develop social and language skills
• Dietary interventions
– Alteration of food to accommodate needs
• Medications
Goldenhar Syndrome
• Congenital
– Means: appears at birth
• Ranges in severity, typically unilateral
– Means: affects one side
• Abnormalities typically involve:
–
–
–
–
–
–
–
–
bones of the face (cheekbones and jaw),
bones of the spine (minor to severe scoliosis)
eyes (up to blindness)
Ears (up to deafness)
Heart
Lungs
Kidneys
Skin tags or pits
Goldenhar Syndrome
What is it like?
• How do you feed a child with a cleft palate?
– http://www.cleftline.org/parents/feeding_your_b
aby (Getting Started)
• How do you communicate?
– Verbally and non-verbally – ASL
• How do you cope?
– You learn, you educate, and you take things one
day at a time.
Jeremy Dale’s Story
Jeremy Dale
• Taken from: http://www.cleftline.org/story_of_the_month/feb04
written by George and Kristine Dale
• “Our son, Jeremy, was born on September 12, 1999. Like typical
parents, we were very excited about the birth of our first child and
were confident that the most perfect little baby would be coming
soon. Our perfect little baby did arrive — 7 weeks early and, a shock
to us, was born with a severe facial abnormality. Jeremy was 3
lbs/10 oz and 16 ½” long and was diagnosed with Goldenhar
syndrome. For Jeremy, Goldenhar syndrome meant a large left
facial cleft, extreme cleft palate, the absence of his left ear, an
underdeveloped left eye and 2 hemi-vertebrae located in the
middle of his spine and at the top of his spine causing congenital
scoliosis. Jeremy was immediately admitted to the NICU and stayed
there for almost 6 weeks.”
Jeremy Dale
• 1st facial surgery February 2000
• 2nd facial surgery 2 weeks later – February 2000
• 3rd facial surgery – March 2000 (after he reached 20
pounds – to repair palate)
• October 2001 – spine surgery (then body cast for 4
months because of scoliosis)
• Total of 9 surgeries in the first 4 years with many more
to come.
• Other than all the medical needs, he is a typical child –
loves to play music, watch TV, etc. He communicates
by sign language because he can not speak.
Jeremy Dale’s Story Continued
• “We’ve all had our struggles with stares and
comments from people who don’t
understand, but we handle each one as it
comes. We try to explain Jeremy’s condition
and educate as many people as we can. To
those who know and love Jeremy, he is still
that ‘perfect’ little baby boy who was born 4
years ago.”