Williams syndrome
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Williams syndrome (Williams-Beuren syndrome) is a rare genetic disorder, occurring in fewer than 1 in every 20,000 live births. It is characterized by a distinctive, "elfin" facial appearance, an unusually cheerful demeanor, ease with strangers, mental retardation coupled with an unusual facility with language, a love for music, cardiovascular problems such as supravalvular aortic stenosis, and hypercalcemia.
Williams shares some features with autism, although persons with Williams syndrome generally possess very good social skills, to the point that this condition is sometimes called "cocktail party syndrome".
Most persons with Williams syndrome are missing about 21 genes on chromosome 7, including the gene for the production of elastin. Inability to produce this protein is likely the root of cardiovascular problems in this syndrome, and may be responsible for differences in brain development as well.
Another symptom of Williams syndrome is lack of depth perception and inability to visualize how different parts assmble into larger objects (for example: assembling a jigsaw puzzle). This problem is caused by a slight defect in the brain that creates a sparsity of of tissue in the visual systems of the brain. A team of researchers at the National Institute of Mental Health used functional magnetic resonance imaging (fMRI) to watch the blood flow of the brains of test subjects while they were performing two tasks involving spatial relations. Persons with Williams syndrome showed weaker activity in the section of the brain associated with spatial relations. Scans of brain anatomy of test subjects with Williams indicated a deficit of brain tissue in an area of the same section of the brain mentioned above. This deficit partially blocks transmission of visual information to the spatial relations region of the brain. In the test, all participants of the study measured in the average intelligence range to remove the possibility that the retardation aspect of Williams syndrome may have had an effect on the visual systems of the tested individuals.
See also
References
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External links
- Williams Syndrome Association (http://www.williams-syndrome.org)
- Williams-Beuren syndrome at Online Mendelian Inheritance in Man (http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=194050)
- Rare Deficit Maps Thinking Circuitry (http://www.sciencedaily.com/releases/2004/09/040902090929.htm)
- Williams Syndrome and Savant Syndrome (http://www.wisconsinmedicalsociety.org/savant/willsynd.cfm)
- Summary of Discussion of Williams Syndrome, Autism, and Consciousness (http://www.udel.edu/billf/willautconsc.html)fr:Syndrome de Williams