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Williams syndrome
Classification and external resources
ICD-10 Q93.8
ICD-9 758.9
OMIM 194050
MedlinePlus 001116
eMedicine ped/2439
MeSH D018980

Williams syndrome (WS or WMS; also Williams–Beuren syndrome or WBS) is a rare neurodevelopmental disorder caused by a deletion of about 26 genes from the long arm of chromosome 7.[1] It is characterized by a distinctive, "elfin" facial appearance, along with a low nasal bridge; an unusually cheerful demeanor and ease with strangers; developmental delay coupled with unusual (for persons who are diagnosed as developmentally delayed) language skills; 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.[2]

Contents

Symptoms

The most common symptoms of Williams syndrome are mental retardation, heart defects, and unusual facial features. Other symptoms include: failure to gain weight appropriately and low muscle tone. Individuals with Williams syndrome are highly verbal and overly sociable (having what had previously been described as a "cocktail party" type personality), but lack common sense and typically have inhibited intelligence. Individuals with WS hyperfocus on the eyes of others in social engagements.[3] Phenotypically, patients tend to have widely spaced teeth, a long philtrum, and flattened nasal bridge.[4] Individuals with Williams syndrome also experience many cardiac problems, commonly heart murmurs and the narrowing of major blood vessels as well as supravalvular aortic stenosis (SVAS). Other symptoms may include many gastrointestinal problems, such as abdominal pain and diverticulitis, as well as hormone problems, the most common being hypercalcemia (elevated calcium levels in the blood). Hypothyroidism has been reported to occur in children, yet there is no proof of it occurring in adults, whereas diabetes has been reported to occur in adults with WS as young as 21 years old.[5]

People with Williams syndrome often have hyperacusis and phonophobia which resembles noise-induced hearing loss, but this may be due to a malfunctioning auditory nerve.[6][7] However, individuals with the WS can also tend to demonstrate a love of music[2], and appear significantly more likely to possess perfect pitch.[8]

There also appears to be a higher prevalence of left-handedness and left-eye dominance in those with Williams.[9] Individuals with Williams syndrome also report higher anxiety levels as well as phobia development, which may be associated with hyperacusis.[10]

Furthermore, individuals with Williams syndrome have problems with visual processing, but this is related to difficulty in dealing with complex spatial relationships rather than to issues with depth perception.[11]

While patients with Williams syndrome often have abnormal proficiency in verbal skills, they do not perform better on verbal tasks than average. This syndrome is characterized more by a deficiency in other areas of processing. Williams syndrome is notable in that respect in that it represents a double dissociation between verbal and spatial processing.

Treatment

Currently, there is no known cure for Williams syndrome. Suggestions include avoiding taking extra calcium and vitamin D, and treating high levels of blood calcium, if present. Blood vessel narrowing can be a significant health problem as well, and is treated on an individual basis. Physical therapy is helpful to patients with joint stiffness. Developmental and speech therapy can also help these children (for example, verbal strengths can help make up for other weaknesses). Other treatments are based on a patient's particular symptoms.[4] Guidelines published by the American Academy of Pediatrics include cardiology evaluations, developmental and psychoeducational assessment, and many other examination, laboratory, and anticipatory guidance recommendations.[12]

Cause

Williams Syndrome genes[13][14]
ASL · BAZ1B · BCL7B · CLDN3 · CLDN4
CLIP2 · EIF4H · ELN · FZD9 · FKBP6
GTF2I · GTF2IRD1 · HIP1 · KCTD7
LAT2 · LIMK1 · MDH2 · NCF1
NSUN5 · POR · RFC2 · STX1A · TBL2
TRIM50 · TRIM73 · TRIM74
WBSCR14 · WBSCR18 · WBSCR21
WBSCR22 · WBSCR23 · WBSCR24
WBSCR27 · WBSCR28

Williams syndrome is caused by the deletion of genetic material from the region q11.23 of chromosome 7. The deleted region includes more than 25 genes, and researchers believe that the loss of several of these genes probably contributes to the characteristic features of this disorder. CLIP2, ELN, GTF2I, GTF2IRD1, and LIMK1 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, learning disabilities, and other cognitive difficulties seen in Williams syndrome.[15]

Effects on the nervous system

Because of the multiple genes that are missing in people with Williams syndrome, there are many effects on the brain, including abnormalities in the cerebellum, right parietal cortex, and left frontal cortical regions. This pattern is consistent with the visual-spatial disabilities and problems with behavioral timing often seen in WS. Frontal-cerebellar pathways are involved in behavioral timing, and the parietal-dorsal areas of the neocortex handle visual processing that supports visual-spatial analysis of the environment (but not faces). People with WS are often affable and hyperverbal – often blurting – which demonstrates the decreased inhibition ability that stems from dorsal-frontal deficits.[16] There have also been studies that show that the amygdala of a person with Williams syndrome has greater volume than the average person's, and given that the amygdala controls a human's sense of fear, it can be seen why WS individuals can so willingly talk to anyone – including strangers.[17]

Epidemiology

Williams syndrome has an estimated prevalence of 1 in 7,500 to 1 in 20,000 births..[1]

In popular culture

In the feature film, Fish Don't Blink, Lea Thompson's character, Clara, is shown to have William's Syndrome. She is very friendly and can hear things which are too soft (like a noise from far away) for other people to hear, including what their giant, pet catfish, Charley, seems to be saying! "Clara has the developmental IQ of a child of 10"..."but I have the genius of a normal person"

Williams syndrome was featured in a 2007 episode of Law & Order: Special Victims Unit entitled "Savant," in which a girl with the condition is the only witness to the attack of her mother. The girl did not see the attacker but heard him speak, and her absolute pitch helped the police catch her mother's assailant.

A web-based reality show "The Specials" features a young man, Lewis, who has Williams Syndrome in addition to four other housemates who have Down Syndrome.[18]

Briefly mentioned in the episode "No More Mr. Nice Guy" on House as a possible diagnosis for the patient's affliction.

MTV aired a show called "How's Your News?" which features three cast members with Williams Syndrome.

References

  1. ^ a b Martens MA, Wilson SJ, Reutens DC (2008). "Research Review: Williams syndrome: a critical review of the cognitive, behavioral, and neuroanatomical phenotype". J Child Psychol Psychiatry 49 (6): 576–608. doi:10.1111/j.1469-7610.2008.01887.x. PMID 18489677. 
  2. ^ a b Dobbs, David (July 8, 2007). "The Gregarious Brain.". New York Times. http://www.nytimes.com/2007/07/08/magazine/08sociability-t.html. Retrieved 2007-09-25. "If a person suffers the small genetic accident that creates Williams syndrome, he’ll live with not only some fairly conventional cognitive deficits, like trouble with space and numbers, but also a strange set of traits that researchers call the Williams social phenotype or, less formally, the “Williams personality”: a love of company and conversation combined, often awkwardly, with a poor understanding of social dynamics and a lack of social inhibition." 
  3. ^ Riby DM, Hancock PJ (2008). "Viewing it differently: Social scene perception in Williams syndrome and Autism". Neuropsychologia 46 (11): 2855–60. doi:10.1016/j.neuropsychologia.2008.05.003. PMID 18561959. 
  4. ^ a b "Williams Syndrome". MedlinePlus Medical Encyclopedia. 2009
  5. ^ Colleen A. Morris, Howard M. Lenhoff, Paul P. Wang (2006). Williams–Beuren syndrome: research, evaluation, and treatment. pp. 107–132. 
  6. ^ Gothelf D, Farber N, Raveh E, Apter A, Attias J (February 2006). "Hyperacusis in Williams syndrome: characteristics and associated neuroaudiologic abnormalities". Neurology 66 (3): 390–5. doi:10.1212/01.wnl.0000196643.35395.5f. PMID 16476938. http://www.neurology.org/cgi/pmidlookup?view=long&pmid=16476938. 
  7. ^ Johnson LB, Comeau M, Clarke KD (April 2001). "Hyperacusis in Williams syndrome". J Otolaryngol 30 (2): 90–2. doi:10.2310/7070.2001.20811. PMID 11770962. 
  8. ^ Sacks O (May 1995). "Musical ability". Science 268 (5211): 621–2. doi:10.1126/science.7732360. PMID 7732360. 
  9. ^ Van Strien JW, Lagers-Van Haselen GC, Van Hagen JM, De Coo IF, Frens MA, Van Der Geest JN (2005). "Increased prevalences of left-handedness and left-eye sighting dominance in individuals with Williams–Beuren syndrome". J Clin Exp Neuropsychol 27 (8): 967–76. doi:10.1080/13803390490919119. PMID 16207621. 
  10. ^ Blomberg S, Rosander M, Andersson G (2006). "Fears, Hyperacusis and musicality in Williams syndrome". Res Dev Disabil 27 (6): 668–80. doi:10.1016/j.ridd.2005.09.002. PMID 16269236. 
  11. ^ Van der Geest JN, Lagers-van Haselen GC, van Hagen JM, et al. (October 2005). "Visual depth processing in Williams–Beuren syndrome". Exp Brain Res 166 (2): 200–9. doi:10.1007/s00221-005-2355-1. PMID 15965761. 
  12. ^ Committee on Genetics, American Academy of Pediatrics (1 May 2001). "Health care supervision for children with Williams syndrome". Pediatrics 107 (5): 1192–2004. PMID 11331709. http://aappolicy.aappublications.org/cgi/content/full/pediatrics;107/5/1192. 
  13. ^ Merla G, Howald C, Henrichsen CN, et al. (August 2006). "Submicroscopic deletion in patients with Williams–Beuren syndrome influences expression levels of the nonhemizygous flanking genes". Am. J. Hum. Genet. 79 (2): 332–41. doi:10.1086/506371. PMID 16826523. 
  14. ^ Schubert C, Laccone F (November 2006). "Williams–Beuren syndrome: determination of deletion size using quantitative real-time PCR". Int. J. Mol. Med. 18 (5): 799–806. PMID 17016608. http://www.spandidos-publications.com/ijmm/article.jsp?article_id=ijmm_18_5_799. 
  15. ^ "Williams syndrome – Genetics Home Reference". The U.S. National Library of Medicine. 2010. [1]
  16. ^ Cozolino, Louis. The Neuroscience of Human Relationships: Attachment and the Developing Social Brain. 2006. 289–91.
  17. ^ Anna Järvinen-Pasley, Ursula Bellugi, Judy Reilly, Debra L. MILLS, Albert Galaburda, Allan L. Reiss and Julie R. Korenberg (2008). Defining the social phenotype in Williams syndrome: A model for linking gene, the brain, and behavior. Development and Psychopathology, 20 , pp 1–35 doi:10.1017/S0954579408000011
  18. ^ Website: The Specials

Further reading

External links

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