TaySachs Disease

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Tay-Sachs Disease
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What is Tay-Sachs Disease?

• A baby with Tay-Sachs disease appears healthy at
  birth
• Symptoms, which include a slowing in development,
  appear by six months of age.
• Gradually children lose motor skills and mental
  functions.

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• Over time, the child becomes blind, deaf,
  mentally retarded, paralyzed and non responsive
  to the environment.
• A child with Tay Sachs disease will usually die
  by age five.

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• Children with Tay-Sachs disease lack a vital
  enzyme, hexosaminidase A (Hex-A).
• Hex-A is needed for the body to break down a
  fatty waste substance found in brain cells.
• Without Hex-A, this substance accumulates
  abnormally and causes progressive damage until
  the nervous system can no longer sustain life.

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Inheritance

• Tay-Sachs is an inherited disease that only
  occurs when both parents carry a Tay-Sachs gene
  and each parent transmits the defective gene to
  their child.
• A child who inherits two Tay-Sachs genes (one
  from each parent) produces no functional Hex-A
  enzyme and is certain to develop Tay-Sachs
  disease.

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What if a person only has 1 gene for Tay-Sachs?
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• A person with only one Tay-Sachs gene is
  perfectly healthy, but is a Tay-Sachs carrier.

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What if BOTH parents are carriers?
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• When both parents are carriers, there is a 1 in 4
  (25) chance, with every pregnancy, of having a
  child with Tay-Sachs disease.
• When both parents are carriers, there is a 2 in 4
  (50) chance, with every pregnancy, of having a
  child who is a carrier.

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What if only one parent is a carrier?
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• When only one parent is a carrier, there is no
  chance the child will have Tay-Sachs diseas

http//www.tay-sachs.org/taysachs.php
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Huntingtons Disease
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What is Huntingtons Disease?
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• Huntington's disease is a progressive,
  degenerative disease that causes certain nerve
  cells in your brain to waste away.
• People with Huntingtons disease experience
  uncontrolled movements, emotional disturbances
  and mental deterioration.
• Symptoms dont develop until middle age (30 - 50
  years old)

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Inheritance

• Huntington's disease is an inherited condition
  caused by a single abnormal gene.
• Only one copy of the defective gene, inherited
  from either parent, is necessary to produce the
  disease.
• If one parent has the single faulty gene, the
  chance that an offspring will have the defect is
  50

http//www.mayoclinic.com/health/huntingtons-disea
se/DS00401/DSECTION1