Fish Analysis, Smith-Magenis Syndrome

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Chromosomal Locus: 17p11.2

Pseudonyms: Smith Magenis syndrome, 17p11.2 deletion, RAI1 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 Smith-Magenis syndrome critical region in 17p11.2. Approximately 95% of patients with Smith-Magenis syndrome have deletions detectable by FISH.
Methods: A dual-color FISH analysis performed on metaphase cells using probes for Smith-Magenis critical region in 17p11.2 and a chromosome 17 control probe; analysis of 10 metaphase cells and 20 interphase cells
Indications for Use:
  • Patients suspected of having Smith-Magenis syndrome on the basis of clinical findings such as facial dysmorphology, brachycephaly, delayed speech and motor development, self-injurious behavior and sleep disturbances
  • Patients with a possible deletion of chromosome 17p by standard chromosome analysis