Williams Syndrome

 

Introduction

Williams Syndrome is a relatively common genetic disorder, found in 1:10,000 live births.  The disorder results from a deletion on chromosome 7q11.23, a region including the Elastin gene.  This deletion results in variable phenotypes.

 

Clinical Features

  • Characteristic "Elfin" facies.

    elfin.jpg
    http://www.physio-pedia.com/images/7/7c/Williams_Syndrome_Girl.jpg
     
  • Vascular Anomalies commonly include supravalvular aortic stenosis (shown below), however deficiency of elastin can lead to narrowing in any artery.  These vascular anomalies can lead to hypertension.


    as.jpg
    http://wfffun.info/diseases/aortic-supravalvular-stenosis-2/
     
  • Impaired cognition and impaired development with a friendly, outwardly social personality.
  • Endocrine abnormalities, which include short stature, hypercalcemia (irritability, vomiting, constipation, muscle cramps), diabetes mellitus, and hypothyroidism.
  • GU/Kidney abnormalities, such as dysfunctional voiding and nephrolithiasis.
  • Sensitivity to sound and sleep problems.

Patients with Williams Syndrome are good at auditory rote memory and specific aspects of language and are described as having a "cocktail party personality" because of their friendliness .

social.jpg

Nicki Hornbaker, born with Williams syndrome, prepares a cartwheel for her mother. http://www.nytimes.com/2007/07/08/magazine/08sociability-t.html?pagewant...

 

Diagnosis

The diagnosis is clinical, based upon the following features:

  • Dysmorphic facial features
  • Supravalvular aortic stenosis or renal artery stenosis
  • Global cognitive impairment with higher verbal IQ than performance IQ

Clinical diagnosis should be confirmed with FISH (fluorescent in-situ hybridization).

http://2.bp.blogspot.com/-T-swipG-g1U/TiXEdnwbwqI/AAAAAAAAAFw/YAowhGcM0yo/s1600/FISH+test.jpg

FISH assay demonstrating a positive and negative test for Williams Syndrome.  http://2.bp.blogspot.com/-T-swipG-g1U/TiXEdnwbwqI/AAAAAAAAAFw/YAowhGcM0y...

 

Management

The AAP provides guideslines for continued management of childrens with Williams Syndrome (click image below).

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Once diagnosed, children need specialized routine care including:

  • BP measurements in all 4 extremities
  • ECHO
  • Renal ultrasound, possibly VCUG analysis with renal function studies (BUN/Creatinine), UA, serum/urine calcium
  • Audiologic testing at 6-12 months
  • Thyroid function studies

 

Individuals with Williams Syndrome also need annual evaluations of BP, Physicals, Development, Cardiac, Auditory and Visual testing because problems in these areas are often progressive.

 

Furthermore, children with Williams Syndrome in general are smaller than average children of similar age, so special growth charts specific for those with Williams should be used.  The Williams Syndrome association provides modified growth charts (link).

growth.jpg

Modified growth chart for males with Williams Syndrome.  https://williams-syndrome.org/sites/williams-syndrome.org/files/Growth_c...

 

Special Considerations

  • These children should NOT take multivitamins because of inherently increased vitamin D, and should be diligent with use of sunscreen to decrease production of vitamin D.
  • These children also need periodic cardiovascular evaluations as cardiovascular problems are progressive.

 

Resources

Emotional & support resources can be beneficial for families affected by Williams Syndrome to allow for networking with others in a similar situation. Support groups should be offered, in addition to the services of a social or case worker as needed.

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https://williams-syndrome.org/

References

1. Committee on Genetics. “Health Care Supervision for Children with Williams Syndrome” Pediatrics Vol. 107 No. 5 May 1, 2001 pp. 1192 -1204