Fish Analysis, Williams Syndrome

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Chromosomal Locus: 7q11.23

Pseudonyms: Williams-Beuren syndrome, 7q11.23 deletion, Elastin gene deletion
TURNAROUND TIME: 7 to 10 days
TESTING METHODOLOGY: Fluorescence in situ hybridization
  • Collect: 3-5 mL peripheral blood in sodium heparin (green) for children and adults; 1-2 mL peripheral blood in sodium heparin (green) for newborns
  • Min. Collection: 1 mL for newborns; 2 mL for children and adults
  • Transport: peripheral blood in sodium heparin (green) at 20-25°C
  • Stability: Ambient: 24 hours; Refrigerated: 72 hours; Frozen: unacceptable
  • Unacceptable Conditions: Frozen or clotted specimens; specimens in anticoagulants other than sodium heparin

A Cytogenetics Laboratory Test Requisition must accompany the specimen. Contact the Cytogenetics Laboratory at 918-502-1722 to obtain further information.

Test Summary: Test can detect microdeletions of the Williams syndrome critical region including the elastin (ELN) gene in 7q11.23. Approximately 99% of patients with Williams syndrome have a deletion detectable by FISH.
Methods: A dual-color FISH analysis performed on metaphase cells using a probe for the ELN gene on chromosome 7q11.23 and a chromosome 7 control probe; analysis of 10 metaphase cells and 20 interphase cells
Indications for Use:
  • Patients suspected of having Wlliams syndrome on the basis of clinical findings such as distinct facial features, growth retardation, supravalvular aortic stenosis, developmental delay and unique personality