Genetic Disorders

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Genetic Disorders

• Down Syndrome
• Hemophilia
• Sickle-Cell Anemia
• Turners Syndrome
• Klinefelters Syndrome
• Marfan Syndrome
• Albinism

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Downs Syndrome

• Chromosomal Mutation
• Afflicted persons have an extra chromosome 21.
• Mental Retardation, upward slant to the eyes,
  decreased muscle tone, small mouth
• About 1 in 900 babies will be diagnosed
• No treatment

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Nondisjunction- Failure of homologous chromosomes
to separate during meiosis
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Down Syndrome

• Diagnosed using a karotype a picture of
  chromosomes taken during Metaphase of mitosis and
  rearranged to place chromosomes in pairs.
• Presence of three chromosomes is called Trisomy.
  (Here it is trisomy-21)
• Higher percentages of occurrence in mothers over
  the age of 35

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Downs Syndrome
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Hemophilia

• Gene mutation on the X chromosome
• Creates faulty clotting factors so a broken blood
  vessel continues to bleed.
• Diagnosed using blood tests to check for the
  clotting factors
• 1 in 4,000 males
• More common in males because it is a recessive
  X-linked trait

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Hemophilia

• Afflicted persons inject themselves with clotting
  factors after an accident where bleeding wont
  stop on its own

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Sickle-Cell Disease

• Gene Mutation in a blood protein, resulting in
  malformed blood cells
• Found in African-Americans
• A simple blood test confirms diagnosis
• 1 in 375 African-Americans
• Bone marrow transplant can be successful in small
  children

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Sickle-Cell

• Causes anemia (fatigue) and blockage in blood
  vessels

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Turners Syndrome

• Chromosomal Mutation- a
• deletion of one X
• chromosome in females
• (XO- called monosomy)
• Females will have a short
• stature that may require treatment with growth
  hormone, women are sterile
• 1 in 2500 females will have Turners
• Diagnosed with an amniocentesis

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• Amniocentesis is a procedure in which a small
  sample of the amniotic fluid is taken from the
  amniotic sac (the fluid-filled bag that surrounds
  the fetus in a pregnant woman. It
• has the same genetic
• makeup as the fetus.

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Klinefelters Syndrome

• Chromosomal Mutation- afflicted males have an
  extra X chromosome- XXY
• The extra X causes the male to have some female
  features. Underdevelopment of testes and
  infertility
• Caused by nondisjunction of the sex chromosomes
• 1 in 1,000 births

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Klinefelters Syndrome

• Diagnosed in puberty due to presence of abnormal
  features
• Only treatment is testosterone at onset of puberty

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Marfan Syndrome

• Gene mutation in the gene that makes connective
  tissue
• Afflicted are abnormally tall, have long arms,
  hyperflexible joints, caved in chest, heart valve
  problems
• 1 in 10,000 births
• Most people are not diagnosed until an outlying
  problem discovered

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Marfan Syndrome

• Some hormone treatments available

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Albinism

• Gene mutation in the genes that produce melanin
  (the brown pigment found in the skin, hair, and
  eyes)
• Afflicted have blond hair, light colored eyes and
  very pale skin.
• Pale skin causes a higher chance for getting skin
  cancer, and visual impairments from lack of
  melanin in eyes

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Albinism

• Can happen in any race, and is common in animals
  as well
• 1 in 17,000 births

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• Cystic Fibrosis
• Inherited disorder that causes the over
  production of thick mucus that clogs the lungs
  and contributes to repeated infections.
• Avg. life span increased to 32 years.