Autism Spectrum Disorders (ASD)
Wikipost #3 - June 6, 2014
Autism is a neurological disorder that affects 1 in every 100 people; it can range for mild autism (Asperger’s syndrome) to severe autism (classical) and affects every person differently. Autism can result in amazing talents (savantism or savant syndrome) and/or severe disabilities many times simultaneously.
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Different disorders classified as and autism spectrum disorder.


Causes of Autism:
Autism is suspected to be a genetic disorder or at the very least have some genetic factor. Some scientists believe that the genes involved in autism only “set the stage” and that environmental factors trigger the disorder.
Scientists believe that the cause of autism is found in as many as a dozen genes. Mutations in these genes would make the child more susceptible to the disorder or directly cause some of the symptoms. Three of the genes that have been isolated are HOXA1 (involved in brain structures and nerves), RELN (Connections between nerve cells) and GABA pathway genes (communication between nerve cells).
HOXA1.jpg
The HOXA1 gene is found on chromosome 7.
RELN.jpg
The RELN gene is also found on chromosome 7.




Facts about Autism:
  • It’s 4 times more likely to affect boys than girls
  • There is no medical detection or cure for autism
  • Autism is a hidden disability - you can't always tell if someone has it
  • Only 15% of adults with autism in the UK are in full-time paid employment
  • Comorbid conditions often associated with autism include Fragile X, allergies, asthma, epilepsy, bowel disease, gastrointestinal/digestive disorders, persistent viral infections, PANDAS, feeding disorders, anxiety disorder, bipolar disorder, ADHD, Tourette Syndrome, OCD, sensory integration dysfunction, sleeping disorders, immune disorders, autoimmune disorders, and neuroinflammation.

How it Affects the Brain:
The parts of the brain affected by autism is different for women than it is for men, this usually results in different autistic behaviors for each gender. Autism can radically affect the way dendrites grow and develop, they can either be under-developed and have too few branches or they can be over developed and have branches that grow wildly, are too long, too thin and can be easily damaged. But the problems associated with autism aren’t caused by the death or damage of neurons; they are cause by the inability to make the correct connections with each other. Autism main affect two neurotransmitters, serotonin and glutamate, many scientists believe these may account for some autistic behaviors because serotonin affects both emotion and behavior while glutamate plays a role in neuron activity.
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Problems with dendrite growth found in people who have autism.


Parts of the Brain Affected:

Normal vs. Autistic:
Neurotypical
Autistic
Normal amount of nerve fibers making appropriate connections between the various regions of the brain
Excess nerve fibers communicating between various random parts of the brain
Normal neurotransmitters
Imbalances in neurotransmitters
Able to communicate their thoughts, desires and feelings clearly
Unable to communicate clearly or at all.
Can understand other people’s feelings and social cues Social interaction
Can’t relate to other people and do not pick up on social cues
Repetitive behaviors not present
Repetitive behaviors present in early childhood and needed for the person to feel comfortable and function on a daily basis

Sensitivity Issues & Social Problems:
Sensitivity issues do not affect all those who have autism, but are quite common. Any combination of sensitivity problem could be found in someone with autism and it is unlikely that two or more patients would have the same combination.
There are two types of sensitivity issues, hyposensitivity (under-sensitive) and hypersensitivity (over-sensitive).

Sense
Hyposensitive
Hypersensitive
Sight
  • Blurred vision
  • Objects appear dark or lose features
  • Poor depth perception
  • Objects appear bright or ‘jump’ around
  • Images may fragment
  • Easier focus on detail than whole object
Sound
  • Only hear sounds in one ear
  • May not hear certain sounds May enjoy crowded, noisy places
  • Sounds are magnified or distorted
  • Sensitive to sound
  • Can hear conversations from a distance
  • Inability to ignore sounds
Touch
  • Holds others tightly before any sensation is felt
  • High pain threshold
  • Self-harm
  • Enjoys having heavy objects on top of them
  • Touch can be painful and/or uncomfortable
  • Dislikes having anything on hands or feet
  • Can only wear certain types of
    clothing (textures)
Taste
  • Likes spicy foods
  • Will eat anything
  • Has sensitive taste buds
  • Unable to eat foods with certain textures
Smell
  • Have little or no sense of smell
  • May lick things to get a better sense of what they are
  • Any smell can be overpowering
  • Dislikes certain smells (perfume, shampoo, etc.)
Vestibular (Balance)
  • Need to rock, swing or spin to get sensory input
  • Difficulties with sports
  • Car sickness
  • Stopping quickly
  • Needs to have head upright and feet on the ground to feel comfortable
Proprioception (Body Awareness)
  • Cannot judge personal space
  • Difficulty avoid obstacles
  • May bump into people a lot
  • Difficulties with fine motor skills (manipulating small objects)
  • Moves whole body to look at something

*Synaesthesia is a rare disorder experienced by those with an Autism Spectrum Disorder (ASD) where the senses are ‘mixed up’, for example someone might hear the colour blue instead of see it.

These sensory issues contribute to social behavior displayed by some autistic people that could be considered rude or inappropriate to a ‘normal’ person. Things like; not respecting personal space, push people away or overreacting to simple touch could be consider inconsiderate to others while an autistic person would view these behaviors as normal.

Many people with autism are also poor at communicating with others; they often don’t understand facial expressions and body language or don’t make eye contact with the person they’re talking to. This coupled with possible language difficulties they might have can make communication an uncomfortable experience and the person may try and isolate themselves from these situations; they may be viewed as a loner, introvert or recluse.

Effects of Autism:
The extent to which each person is affected varies dramatically some people will never talk while other will be able to master many languages. Some people cannot perform simple addition while others can do advanced calculus.
Some people will be able to communicate with others and live an independent life while those with more severe autism may be disabled to the point where they will need a caretaker for the rest of their lives.
People with autism may have a higher-than-normal amount of the neurotransmitter serotonin in their brain which could lead to an increased chance for depression.

autism-spectrum-conditions.jpg
Anyone with autism could have extreme intelligence, severe disability or both.


References:
http://health.howstuffworks.com/mental-health/autism/autism3.htm
http://www.cam.ac.uk/research/news/autism-affects-different-parts-of-the-brain-in-women-and-men
http://www.childrenshospital.org/news-and-events/research-and-innovation-features/breaking-into-the-autistic-brain
http://www.autismspeaks.org/what-autism/facts-about-autism
http://www.autism.org.uk/about-autism/myths-facts-and-statistics/some-facts-and-statistics.aspx
http://nationalautismassociation.org/resources/autism-fact-sheet/
http://www.autism.org.uk/living-with-autism/understanding-behaviour/the-sensory-world-of-autism.aspx
https://www.nidcd.nih.gov/health/voice/Pages/Communication-Problems-in-Children-with-Autism-Spectrum-Disorder.aspx#3

Further Reading:
http://www.medicalnewstoday.com/info/autism/
http://psychcentral.com/news/2013/03/14/autism-affects-brains-of-children-adults-differently/52602.html
http://treatautism.ca/brain-chemicals/
http://www.webmd.com/brain/autism/autism-spectrum-disorders


Evolution of Marsupials - Wikipost #2

May 2, 2014

Definition:any animal of the order Marsupialia, comprising mammals having no placenta and bearing immature young that complete their development in a pouch on the mother's abdomen.


Examples of Marsupials:
Vombatus_ursinus_-Maria_Island_National_Park.jpg
Wombat
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A Tree Kangaroo and her joey.
Sarcophilus_harrisii_taranna.jpg
Tasmanian Devil




Opossum Wallpaper.jpg
Opossum, one of the few marsupials left in North America
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The koala, a native of Australia
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A kangaroo and her joey
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The extinct thylacine (Tasmanian Tiger)


This video shows the path that marsupials took from their assumed common ancestor to where they are today.

Where are Marsupials From?
Marsupials are believed to have evolved in North America and expanded into South America and the Pacific Rim of Asia. Many species of marsupial then migrated toward Australia and New Zealand, while quite a few of the species left in the Americas went extinct. The many different types of opossum are remnants of the marsupials that once called the Americas home.

Woolly-Opossum-003.jpg
Woolly Opossum
Water-Opossum-Alr1.jpg
Water Opossum
American opossum.jpg
Common/ American Opossum

How did Marsupials Evolve?
phylogenetictree.jpg
Possible phylogenetic tree for the origins of marsupials.

Marsupials are believed to have evolved from Sinodelphys szalayi and possum-like creature whose fossil was found in China, the start of the marsupial’s migration though the Americas and into Australia.
Figure_3.jpg
Sinodelphys szalayi, thought to be the common ancestor of all marsupials.

No one is entirely certain how the pouch possessed by most marsupials came to be, this may be because it is a soft tissue trait or because we have yet to find any fossil record of the species that first started evolving the pouch. However, there are, in general, many different types of pouches present in modern marsupials that are perfectly adapted to their environment.


Modern Marsupials

Today’s marsupials sport pouches that either face forwards, backwards or are merely a fold of skin to guard the young until they’re old enough to be left alone in the nest.

Marsupials like kangaroos and other jumping or climbing individuals have a forward facing pouch so that their young don’t fall out while on the move. Other marsupials, such as the wombat, benefit from their backwards facing pouch because they dig and tunnel regularly; the direction of their pouch ensures that it doesn’t fill up with dirt and suffocate the young. Koala’s, however, have a backwards facing pouch despite being climbers because of this they have evolved and muscle that hold the pouch closed while on the move.
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The forward pouch on a kangaroo.
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Backwards facing pouch on a wombat.
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The unique backwards pouch in present on the koala.


Further Reading:
http://www.pbs.org/wnet/nature/episodes/kangaroo-mob/marsupials-the-evolution-backstory/7464/
Discusses the difference between marsupial mammals and placental mammals and where they may have branched off from one another.

http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1000436
Migration of marsupials and how the different types from different places are linked.

http://www.ucmp.berkeley.edu/mammal/marsupial/marsupial.html
Shows the different types of marsupials present today and mentions some of the extinct ones.

http://animals.about.com/od/marsupials/a/marsupial-facts.htm
Discusses the traits of marsupials and how the differ from placental mammals

References:
http://www.thefreedictionary.com/marsupial
http://www.nhc.ed.ac.uk/index.php?page=493.168.256
http://www.nhc.ed.ac.uk/index.php?page=24.134.165.254
http://www.reddit.com/r/askscience/comments/1qvksp/
http://www.palaeontologyonline.com/articles/2012/fossil-focus-marsupials/








Wikipost #1
Proteus Syndrome

Proteus syndrome first caught the public’s attention when one of the most famous cases, Joseph Merrick, better known as the “Elephant Man”, became part of a human oddities show in a traveling fair during the 1880’s and attracted the attention of Surgeon Frederick Treves who used Merrick’s publicity to raise funds and put him in a nursing home. Because proteus syndrome only affects less than 1 in 1 million people worldwide and is not inherited from a parent, it was not officially identified until 1979.
Joseph_Merrick_carte_de_visite_photo,_c__1889.jpg
Joseph Merrick - the "Elephant Man"

Causes and Symptoms

Proteus syndrome is caused by a mutation in the AKT1 gene in the 14th chromosome. It causes an asymmetrical overgrowth of bones, skin and other tissues; it can also cause neurological abnormalities such as including intellectual disability, seizures, and vision loss. This disorder can also increase one’s risk of developing noncancerous (benign) tumors and blood clots in the arms and legs.


Chromosomes.jpg
Chromosome 14 - location of the AKT1 gene
AKT1.jpg
AKT1 gene


Misdiagnosis

Hemihyperplasia is often mistaken for proteus syndrome because of similar overgrowth, but is actually different in many aspects. For instance hemihyperplasia causes the overgrowth of one half of the body instead of just affecting random parts. It also differs because in being congenital (evident at birth), hemihyperplasia is evident at birth while proteus syndrome only becomes evident at the age of 6 to 18 months.

There is also evidence that hemihyperplasia is hereditary which also differs from proteus syndrome which caused by a mutation in the AKT1 gene during early development before birth.

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Hemihyperplasia




Similar Disorders

Sellars’ syndrome is a condition that is unique to only one person, Mandy Sellars. This condition was originally diagnosed as proteus syndrome because of the overgrowth that on occurred in Sellars’ legs, but was proved to be a mutation in the PIK3CA gene of chromosome 3 and not the AKT1 gene that causes proteus.




MandySellars.jpg
Mandy Sellars only know case of sellars' syndrome





Further Reading:

http://www.mandysellars.com/
http://www.genome.gov/27544873

http://ghr.nlm.nih.gov/condition/proteus-syndrome
http://dermnetnz.org/systemic/proteus.html

Sources:
http://ghr.nlm.nih.gov/condition/proteus-syndrome
https://www.genome.gov/27544895
http://www.proteus-syndrome.org/proteus-syndrome/
http://www.healthline.com/health/hemihypertrophy-hemihyperplasia#Overview