WILLIAMS SYNDROME

'Williams syndrome' (also 'Williams-Beuren syndrome') is a rare genetic disorder, occurring in fewer than 1 in 7,500 live births. It is characterized by a distinctive, "elfin" facial appearance, along with a low nasal bridge; an unusually cheerful demeanor and ease with strangers, coupled with unpredictably occurring negative outbursts; mental retardation coupled with unusual (for persons who are diagnosed as mentally retarded) language skills; a love for music; and cardiovascular problems, such as supravalvular aortic stenosis and transient hypercalcaemia. The syndrome was first identified in 1961 by Dr. J. C. P. Williams of New Zealand.^[1]

Contents

Symptoms

Relativity and Perception

Cause

References

External links

Symptoms

Williams syndrome shares some features with autism (such as difficulty understanding the state of mind of conversational partners^[2]) and Fetal alcohol syndrome (e.g., certain facial features, possible mental retardation, and negative potential outbursts),^[3] although persons with Williams generally possess very good social skills, such that this condition is sometimes called "cocktail-party syndrome". Temple Grandin, author of ''Thinking in Pictures'', has claimed that the brain abnormalities of Williams syndrome are the opposite of those of autism.^[4] There also appears to be a higher prevalence of left-handedness and left-eye dominance in those with Williams,^[5] and cases of absolute pitch appear to be significantly higher amongst those with the condition.^[6]

Relativity and Perception

Another symptom of Williams syndrome is lack of depth perception and an inability to visualize how different parts assemble into larger objects (in assembling jigsaw puzzles, for example). This problem is caused by a defect in the brain that creates a sparsity of tissue in the visual systems of the brain. When asked to perform tasks involving spatial relations, with their brains scanned by fMRI, people with Williams Syndrome showed weaker activity in the dorsal area of the brain, which is along the top and back of the brain and associated with vision and spatial relations. (fMRI measures brain activity by measuring blood flow through different parts of the brain.)
When asked to copy a picture, those with Williams Syndrome drew the small details while those diagnosed with Down Syndrome drew the big picture.

Cause

Williams syndrome is caused by the deletion of genetic material from the region q11.2 of chromosome 7. The deleted region includes more than 20 genes, and researchers believe that the loss of several of these genes probably contributes to the characteristic features of this disorder. , ELN, , , and are among the genes that are typically deleted in people with Williams syndrome. Researchers have found that loss of the ''ELN'' gene, which codes for the protein elastin, is associated with the connective-tissue abnormalities and cardiovascular disease (specifically supravalvular aortic stenosis (SVAS) and supravalvular pulmonary stenosis (SVPS)) found in many people with this syndrome. Studies suggest that deletion of ''LIMK1'', ''GTF2I'', ''GTF2IRD1'', and perhaps other genes may help explain the characteristic difficulties with visual–spatial tasks. Additionally, there is evidence that the loss of several of these genes, including ''CLIP2'', may contribute to the unique behavioral characteristics, mental retardation, and other cognitive difficulties seen in Williams syndrome.

References

1. "The Gregarious Brain," by David Dobbs. The New York Times, July 8, 2007. [1]
2. "Rare Disorder Offers Fresh Insight into Language" by Rhitu Chatterjee. National Public Radio. 10 Jul 2006 (text only). [2]
3. CDC. (2004). ''Fetal Alcohol Syndrome: Guidelines for Referral and Diagnosis''. Can be downloaded at http://www.cdc.gov/fas/faspub.htm
4. Interview with Temple Grandin at Wrong Planet Page accessed 5 October 2006
5. Van Strien JW, Lagers-Van Haselen GC, Van Hagen JM, De Coo IF, Frens MA, Van Der Geest JN. "Increased prevalences of left-handedness and left-eye sighting dominance in individuals with Williams-Beuren syndrome." ''J Clin Exp Neuropsychol.'' 2005 Nov;27(8):967-76. PMID 16207621.
6. Musical Ability, , Oliver, Sacks, Science, 1995

External links

★ Williams Syndrome Association

★ Williams Syndrome and Savant Syndrome

★ Summary of Discussion of Williams Syndrome, Autism, and Consciousness

★ Williams Syndrome: It's Not a Fairy Tale from National Public Radio, 14 October 2006

★ Musical Behavior in a Neurogenetic Developmental Disorder: Evidence from Williams Syndrome

★ The Gregarious Brain by David Dobbs, New York Times Magazine, July 8, 2007.

★ Williams Syndrome Foundation homepage