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Kendra's picture



    Over Winter Break, I watched massive amounts of television, including multiple marathons of Law and Order: Special Victims Unit. Overall, I am a huge fan of the show but one episode in particular stood out to me. Entitled 'Savant', the storyline of this episode involved a little girl who was the only witness to her mother's attack, the catch being that she did not actually see the attacker, but only heard him speak. It was her absolute pitch that enabled the investigators to eventually pinpoint her mother's assailant. The little girl was -not surprisingly- classified as a musical genius but also a person who has a condition called Williams Syndrome, a condition whose upside is the heightening of both social friendliness and ability for musical talent. Watching this episode of Law and Order SVU only heightened my interest in learning more about mental disorders. I wondered why some people- and not others- developed conditions such as Williams syndrome and more specifically what eventually happens to the brain structure of people with Williams syndrome? Most importantly, how does the gene depletion that occurs during Williams syndrome cause the overfriendly personality that most people with Williams have?
First identified in 1961 by Dr. J.C.P. Williams of New Zealand, Williams syndrome was noticed in a number of young cardiac patients at Greenlane Hospital in Auckland [1]. Dr. Williams noticed that some of the patients were "small in stature, had elfin facial features and seemed friendly but in some ways were mentally slow" [1] Because of the rarity of Williams Syndrome, it was put on the back burner of the study of mental disorders until the early 1990's, when scientific investigators began to be attracted to Williams syndrome on two fronts. The first being that the "dramatic peaks and valleys in the abilities of affected individuals will provide a new window to the organization and adaptability of the normal brain" [2] and the second being the eventual uncovering of the genetic abnormalities that are ultimately responsible for Williams syndrome. On the surface, people with Williams syndrome love to be very amiable and either listen to or make music, but beneath the surface, Williams syndrome is caused by a faulty recombination during meiosis, when the DNA's double helix is divided into two separate halves. In Williams, 25 teeth on chromosome 7 are torn loose during the separation and this DNA strand eventually forms an embryo where "the segment of the DNA missing those 25 genes can't do its work" [1]. How does losing 25 genes in the embryonic state of a human cause that same person to be inclined to friendliness and a good ear for music?
Though Williams syndrome is a rare genetic disorder only affecting 1 in 7,500 people, the missing genes and the environment of the person with Williams is what makes this condition difficult to live with. In studying the social behavior of Nicki Hornbaker, a 19 year old with Williams syndrome two famed neuroscientists, Albert Galaburda and Allan Reiss concluded from modern genetics: "genes do shape behavior and personality, and they do so by creating brain structures and functions that favor certain abilities and appetites more than others" [1]. Although genes are a strong determinant of how the brain will ultimately be structured, it is the environment of the person with Williams syndrome that further develop the structures of the brain. According to Reiss, people with Williams struggle to understand space and abstraction but readily finds it a reward listening to speech and looking at faces [1]. As an infant encounters more of these rewarding experiences, these neurons gain more strength while other neural connections begin to diminish.
    Galaburda and Reiss' work further went on to show that the genes deleted were in fact "patterning genes", genes that essentially direct both embryonic development and brain formation. With these patterning genes missing, the balance between certain areas of the brain are underdeveloped and in the case of those with Williams syndrome, there is an imbalance between the dorsal and ventral areas of the brain which causes people with Williams syndrome to have a weakness in some cognitive area and great strengths in other areas. Those with Williams syndrome typically perform better on tasks involving spoken language and memorization rather than on visual-spatial tasks like drawing and writing. [3].
    The brain structure of a person with Williams syndrome has long been debated since the research is not nearly complete, but speculations that have been raised adds a sense of clarity tot he root cause of Williams syndrome. One study concerning the brain structure of those with Williams suggests that the primary auditory cortex and the plenum temporal are unusually enlarged in people with Williams, but this had only been proven on a small number of Williams brains [2]. One of the more recent findings in the brain of a Williams person was a dead neural connection between the orbitofrontal cortex (OFC) and the amygdala. This is significant because with this disconnect came misunderstandings of possibly dangerous social situations in people with Williams. Because the OFC prioritize certain behaviors in social contexts and communicates with the amygdala when faced with threatening faces, this disconnect causes a Williams person to be overly friendly to strangers and unable to pick up social queues, such as sarcasm or irony.  If those with Williams are unable to pick up these social queues because of their brain structure caused by the missing genes, these neural circuits are unable to be developed and will ultimately be lost.
    The best way for researchers to clearly rationalize their set of observations concerning Williams syndrome, they decided to compare those with Williams to a group of normal children as well as people with a genetic disorder that had been studied long before Williams, Down syndrome. After analyzing the number of tests between the three groups of children, it was found that Williams children performed better in different skills than the Down syndrome children and in some cases, the opposite was true. Because the Williams children did better than the Down children in verbal exercises and the Down children proved to be better in visual activities such as copying a drawing shows that "deficits in the two groups may stem from different brain anatomy" [2]. Recognizing these differences between these two syndromes help scientists see these disorders in a different light. No longer did being mentally challenged mean that the person was not talented outside of the initially believed mental capacity of a skill. People with Williams do lack social cognition and suffer from many physical ailments, such as premature aging, but many of them are extremely talented when it comes to music, language skills and being overall friendly. Learning about the research behind Williams syndrome allows the reader to witness the other side of being mentally challenged, and accepting the way in which these genes ultimately affect ones brain structure enables us to consider other skills that also make the person who they are, a 'savant' of sorts.

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Paul Grobstein's picture

more on sociability and the brain

See The Friendly Gene, and my comments on it. What CAN one make of both the similarities and the differences between Williams and Down's syndromes? What are they telling us about the brain in relation to interpersonal interactions? Probably also relevant is autism and psychopaths and sociopaths.