Today

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Todays Date Here

• Objective Here!

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Brainteaser

• What is the center of gravity?

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Human Genetic Disorders
And Karyotypes
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What is a Karotype?

• A picture of the collection of chromosomes found
  in an individuals cells
• Tells you the chromosome of
• an organism
• 46 in humans
• Tells you the sex of an organism
• XX Female XY Male
• Can indicate whether or not a chromosomal
  abnormality is present.

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Karyotype

• MALE

• FEMALE

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Chromosomal Abnormalities

• Monosomy

• Trisomy

• the condition in which a diploid cell is missing
  a chromosome

• the condition in which a diploid cell has an
  extra chromosome

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Nondisjunction Disorders

• Caused by an abnormal number of a particular
  chromosome

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Types of Chromosomal Abnormalities

• Down Syndrome
• Extra 21st Chromosome
• Symptoms
• Distinctive shaped eyes
• Cognitive heart abnormalities
• Simian folds
• Below average cognitive ability
• Protruding tongue
• Short limbs

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Types of Chromosomal Abnormalities

• Turners Symdrome
• 1 X chromosome and no match
• Symptoms
• Short stature
• Webbed neck
• Broad chest
• Non-functioning ovaries
• sterility

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Types of Chromosomal Abnormalities

• Klienfelters Syndrome
• 2 X chromosomes and 1 Y
• Most common chromosomal abnormality
• Symptoms
• Underdeveloped male sex characteristics
• Reduced fertility
• Slightly feminime characteristics
• Potential language impariment

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Autosomal Recessive Disorders

• Requires the inheritance of two recessive alleles
• Error found on chromosomes 1 - 22

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Cystic Fibrosis (CF)

• Monogenic
• Cause deletion of only 3 bases on chromosome 7
• Fluid in lungs, potential respiratory failure
• Common among Caucasians1 in 20 are carriers
• Therefore is it dominant or recessive?

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Sickle Cell Anemia

• An inherited, chronic disease in which the red
  blood cells, normally disc-shaped, become
  crescent shaped. As a result, they function
  abnormally and cause small blood clots. These
  clots give rise to recurrent painful episodes
  called "sickle cell pain crises".

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Albinism

• Inability to make melanin which gives
  pigmentation to hair, eyes, and skin
• Mutation in the tyrosinase gene on chromosome 11
• Tyrosinase is an enzyme that functions in the
  production of melanin
• Is it monogenic or chromosomal?

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Phenylketonuria (PKU)

• One of the most common causes of mental
  retardation
• Mutation in gene for the enzyme phenylalanine
  hydroxylase on chromosome 12
• This enzyme converts the amino acid phenylalanine
  to the amino acid tyrosine

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Phenylketonuria or PKU

• People with PKU cannot consume any product that
  contains aspartame.
• PKU is a metabolic disorder that results when the
  PKU gene is inherited from both parents
  (recessive or dominant? Monogenic or
  chromosomal?)
• Caused by a deficiency of an enzyme which is
  necessary for proper metabolism of an amino acid
  called phenylalanine.

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Tay-Sachs disease

• Monogenic, autosomal recessive
• Central nervous system degrades, ultimately
  causing death.
• Most common among people of Jewish, eastern
  Europe descent.
• About 1/30 American Jews are carriers of
  Tay-Sachs disease

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Autosomal Dominant Disorders

• Require the inheritance of only one copy of the
  allele
• Found on chromosomes 1 - 22

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Achondroplasia

• The most common form of dwarfism
• 1/25,000 births result in achondroplasia
• Caused by a mutation in the gene for the
  Fibroblast growth factor receptor 3 protein
• This protein functions in normal bone growth
• This gene is found on chromosome 4

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Marfan Syndrome

• People with Marfan characteristically are tall
  with very long limbs and fingers
• It is believed that Abraham Lincoln had Marfan
  Syndrome
• Many times people do not know they have the
  disease and yet are susceptible to aortic rupture
• 1/5,000 people in the US have Marfan Syndrome

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Huntingtons Disease

• Huntington's disease (HD) is an inherited,
  degenerative brain disorder which results in an
  eventual loss of both mental and physical
  control. The disease is also known as
  Huntington's chorea. Chorea means "dance-like
  movements" and refers to the uncontrolled motions
  often associated with the disease.

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X-Linked Recessive

• Females have to inherit two copies of the gene
• Males have to inherit one copy on the X from
  their mother

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Hemophilia, the royal disease

• Hemophilia is the oldest known hereditary
  bleeding disorder.
• Caused by a recessive gene on the X chromosome.
• There are about 20,000 hemophilia patients in the
  United States.
• One can bleed to death with small cuts.

• The severity of hemophilia is related to the
  amount of the clotting factor in the blood. About
  70 of hemophilia patients have less than one
  percent of the normal amount and, thus, have
  severe hemophilia.

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X-linked Inheritance pedigree chart
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Hemophilia

• About 18,000 people (almost all male) in the US
  have hemophilia
• 400 babies in the US each year are born with
  hemophilia
• In the 1980s approximately 10,000 children were
  infected with HIV because of transfusions for
  hemophilia
• With proper treatment, hemophiliacs can live a
  normal life

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Fragile X Syndrome

• Most common cause of genetic mental impairment
• Mutation in the Fragile X Mental retardation
  protein believed to help brain cells develop
  function normally

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Fragile X Syndrome

• In the promoter region for the FMR1 gene, there
  are CGG repeats
• In the normal gene there are 6 40 repeats
• In the abnormal gene there may be hundreds of
  repeats
• The more CGG is repeated the more severe the
  disease
• Heterozygous females make enough FMR to have
  normal intelligence
• 1/2000 males have Fragile X 1/4,000 females

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Fragile X