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The Kleberg Cytogenetics Laboratory offers a fluorescence in situ hybridization (FISH)-based assay for identifying the deletions on 17p11.2 associated with Smith-Magenis syndrome. Clinical Features:Smith-Magenis syndrome is associated with a distinct phenotype of brachycephaly with midface hypoplasia, short, broad hands, mental retardation, sleep disturbances and self-abusive behavior. Reasons for Referral:Patients with clinical features suggestive of Smith-Magenis Syndrome may be tested for deletions of 17p11.2 by FISH simultaneously with high-resolution chromosomal analysis (if not previously performed). Prenatal diagnosis may be performed if an affected family member has been studied in our laboratory and shown to have a deletion detectable by FISH. Please call regarding all prenatal samples. Testing Methodology:FISH is the application of fluorescently labeled DNA molecules to metaphase chromosomes and interphase nuclei for the detection of chromosome abnormalities and alterations. It is a rapid, reliable and direct approach for identifying patients with microdeletions or microduplications. FISH analysis for Smith-Magenis syndrome is performed on metaphase chromosomes. The absence of a hybridization signal indicates a deletion. The Kleberg Cytogenetics Laboratory uses a FLI 1 gene probe for detecting deletions in the Smith-Magenis syndrome critical region on 17p11.2. The majority of deletions are detected using high-resolution chromosome analysis, however, FISH is helpful for confirming the deletion in unclear cases or for detecting submicroscopic deletions. Specimen Requirements:Whole blood in sodium heparin (green-top) tubes: Shipping and Handling:All tubes must be labeled with the patient's testname and date of birth, and a completed requisition form must accompany each sample. If the laboratory is billing the patient's insurance, please enclose a copy of the insurance card. Ship specimens for overnight delivery at ambient temperature. Please notify the laboratory of incoming samples. Turnaround Time:7-10 days CPT Codes and Prices:88230, 88271, 88273, 88291 References:1. Chen, et al. (1995) Am. J. Hum. Genet. 56: 175-182. Forms: >> Cytogenetics
Requisition Test Code:8478 |