Karyotyping

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Karyotyping

• Does it all add up?

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Karyotype a picture of paired chromosomes

• Match chromosomes basted on
• Size biggest pair is pair 1 smallest is pair 22
• and banding pattern (staining pattern)
• First 22 pairs of chromosomes are called
  autosomes
• Last pair of chromosomes are called the sex
  chromosomes.
• Determine gender. XX are females and XY are
  males.

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Arrange chromosomes by size biggest to smallest
autosomes
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How do you get the chromosomes to know?

• Blood samples
• Amniocentesis

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Amniocentesis
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Amniocentesis

• First remove cells
• Culture/grow cells
• Find cells going through mitosis metaphase.
  Why?
• Stain chromosomes
• Take picture
• Pair up chromosomes count. Normal? Abnormal?
• Inform parents. Counsel parents.

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Cri-du-chat

• This syndrome is caused by a deletion of the end
  of the short (p) arm of chromosome 5.
• Found in people of all ethnic backgrounds, more
  common in females by a 3-1 ratio.
• Abnormal rate of growth of the larynx-- The cry
  is said to have a cat like quality, which is how
  the syndrome got the name "cry of the cat."
• Unusual facial features microcephalic (small
  head size).
• They do not grow and develop at a normal rate.
• Hypotonia or poor muscle tone often inhibits the
  development of eating habits.
• About 30 of all children suffer from congenital
  heart defect.
• All patients with cri du chat show signs of
  mental retardation.

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Cri-du-chat
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Cri-du-chat karyotype
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Downs Syndrome

• The result of an extra copy of chromosome 21.
  People with Down syndrome have 47 chromosomes.
• Down syndrome affects 1700 children and alters
  the child's phenotype either moderately or
  severely
• characteristic facial features, short stature
  heart defects
• susceptibility to respiratory disease, shorter
  lifespan
• prone to developing early Alzheimer's and
  leukemia
• often sexually underdeveloped and sterile,
  usually some degree of mental retardation.
• Down Syndrome is correlated with age of mother
  but can also be the result of non-disjunction of
  the father's chromosome 21.

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Downs Syndrome
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Downs Syndrome

• Different forms trisomy (3) of 21st chromosome

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Philadelphia translocation
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Philadelphia translocation

• Philadelphia chromosome or Philadelphia
  translocation is a specific chromosomal
  abnormality that is associated with chronic
  myelogenous leukemia (CML). It is the result of a
  reciprocal translocation between chromosome 9 and
  22
• 95 of people with CML have this abnormality

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Philadelphia translocation
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Tuners syndrome

• Common symptoms of Turner syndrome include
• Short stature
• Lymphedema (swelling) of the hands and feet Broad
  chest (shield chest) and widely spaced nipples
• Low hairline
• Low-set ears
• Reproductive sterility
• Rudimentary ovaries
• Amenorrhoea, or the absence of a menstrual period
  
• Increased weight, obesity
• Shield shaped thorax of heart
• Shortened metacarpal IV
• Small fingernails

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Turners Syndrome
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Turners Syndrome
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Klinefelters syndrome

• Don't make as much of the male hormone
  testosterone
• Teenagers with Klinefelter's syndrome may have
  less facial, body hair, may be less muscular
• By adulthood, XXY males look similar to males
  without the condition, although they are often
  taller. They are also more likely than other men
  to have certain health problems, such as
  autoimmune disorders, breast cancer, vein
  diseases, osteoporosis, and tooth decay.

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Klinefelters Syndrome
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Jacobs

• Males affected with XYY are
• sometimes taller than average
• increased risk of learning disabilities and
  delayed speech and language skills.
• Developmental delays and behavioral problems have
  also been documented, but these characteristics
  vary widely among affected boys and men.
• Most males affected with XYY have normal sexual
  development and are able to conceive children.
• About 1 in 1,000 males worldwide are affected
  with 47, XYY syndrome.

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Jacobs syndrome
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Triple X chromosome

• females. 11000 live births - healthy and fertile
  - usually cannot be distinguished from normal
  female except by karyotype

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Edwards Syndrome
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Edwards Syndrome

• Individuals with trisomy 18 often have
• a low birth weight a small, abnormally shaped
  head a small jaw and mouth clenched fists with
  overlapping fingers heart defects and
  abnormalities of other organs.
• Due to the presence of several life-threatening
  medical problems, many infants with trisomy 18
  die within their first month. Five percent to 10
  percent of children with this condition live past
  their first year.
• Most cases of trisomy 18 are not inherited, but
  occur as random events during the formation of
  eggs and sperm.

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Patau Syndrome
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Patau Syndrome

• Serious eye, brain, circulatory defects as well
  as cleft palate. 15000 live births. Children
  rarely live more than a few months.
• Complications begin almost immediately.
  Complications may include
• congenital heart disease.
• Breathing difficulty or lack of breathing (apnea)
  
• Deafness
• Feeding problems
• Heart failure
• Seizures
• Vision problems