This presentation is for coursera students who have taken Understanding the Brain: The Neurobiology of Everyday Life with Dr. Peggy Mason

1. +
Tay –Sachs Disease
By: Sharmin Shanur
Student of Understanding the Brain: The Neurobiology
of Everyday Life

2. + Tay- Sachs Disease (The video from which my inspiration to
explore Tay-Sachs Disease came from)
http://www.youtube.com/watch?v=RzEpkBU-ITA

3. +
What is Tay- Sachs Disease?
 Tay-Sachs is an inherited disorder that destroys neurons in
both the brain and the spinal chord.
 Tay- Sachs occurs due to a mutation in the HEXA gene, which
carries instructions for making a portion of an enzyme called
beta-hexosaminidase A.
 Beta-hexosaminidase A plays a critical role in the brain and
spinal chord because it helps break down GM2 ganglioside and
acts as a recycling material.
 Mutations in HEXA disrupt beta-hexosaminidase A from
breaking down GM2 gangliosides.
 This can have deleterious repercussions because the substance
(GM2 gangliosides) will build up to toxic levels and cause the
destruction on neurons.

4. +
What is Tay-Sachs Disease? Cont.
 The most common form of Tay-Sachs is in the infantile form,
where kids appear to mentally and physically develop at a normal
rate but begin to slow down around the age of 3-6 months
 Initial symptoms begin with muscle atrophy and a lack of motor
movements
 However, as the disease progresses, children suffer seizures,
vision and hearing loss, intellectual disabilities, and eye
abnormalities.
 Most cases of Tay-Sachs are in the infantile form, however it can
occur in adolescents and adults.
 Symptoms for adolescents and adults are less severe, but include
ataxia, problems with movements, speech impediments, and mental
illness.

5. +
Tay- Sachs Disease

6. +
What Parts of the Nervous Systems
are Active?
 Throughout the progression of Tay-Sachs all parts of the nervous
system deactivate and are destroyed by the GM2 gangliosides.
 Basically in patients with Tay-Sachs, at the end of their lives, no
part of the nervous system is active.
 Based on the video on the first slide, one aspect of the brain that
seems to be active are the ocular motor verve, trochlear nerve,
and the abducens nerve (however in time these nerves will slowly
degenerate)
 The CNS (Central Nervous System) is destroyed by the
gangliosides
 Due to the atrophy of all parts of the nervous system, Tay-Sachs
patients will slowly lose motor control, voluntary muscle control, suffer
seizure, mental deficits, blindness, and paralysis of the limbs.
 Based on the symptoms aforementioned, it can be surmised that the
motor cortex is heavily affected by the build up of GM2 Gangliosides.

7. +
Which Parts of the Nervous System
Are Impaired
 As stated by the previous slide, the CNS is partially, if not
completely destroyed.
 Many Tay-Sachs victims suffer blindness therefore their
occipital lobe(dorsal and ventral streams) are heavily affected
 The cerebellum, which helps control motor behavior, is as
rendered for the worse. The cerebellum is also associated with
learning and considering that after the first few months of living,
Tay-Sachs victims fail to learn new motor behaviors.
 Tay-Sachs victims cannot make fine movements and therefore
their motor cortex is impaired.

8. +
How This Course Has Helped Me
Analyze the Events Around Me
 Quite frankly, upon entering this course, I was a complete novice
to the subject matter of neurobiology. I had absolutely no spatial
recognition of different parts of the brain and never knew that there
are different pathways in our brain that control different aspects of
our lives. Now whenever I see a person with Ataxia or
Huntington’s disease, I realize that their motor pathways have
been blocked or their cerebellum in having a few “technical
problems.” Also, even if I see a completely normal person, I can
analyze what controls their bodies, moods, memory, etc.
 However, I will say, neurobiology is still a subjects I lack a great
amount of knowledge of; but I do know that the lessons taught
here will help me exceed in the subject and understand far more
complex problems.

9. +
Bibliography (Websites Used)
 http://www.btbuddies.org.uk/about-high-grade-brain-
tumours/areas-of-the-brain-and-their-functions.html
 http://en.wikipedia.org/wiki/Eye_movement
 http://www.ninds.nih.gov/disorders/taysachs/taysachs.htm
 http://ghr.nlm.nih.gov/condition/tay-sachs-disease
 http://www.ntsad.org/
 http://www.genome.gov/10001220
 http://www.mayoclinic.org/diseases-conditions/tay-sachs-
disease/basics/definition/CON-20036799
 http://www.tay-sachs.org/taysachs_disease.php