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| The Kleberg Cytogenetics Laboratory offers a fluorescence in situ hybridization (FISH)-based assay for identifying deletions associated with isolated aniridia and WAGR syndrome. Clinical Features:Aniridia is a developmental defect of the eye that may occur sporadically or may be inherited in a family. In the majority of cases, aniridia is an isolated finding, however, it may rarely occur as part of the contiguous gene deletion syndrome, WAGR (Wilms tumor, aniridia, genitourinary anomalies and mental retardation). The features of WAGR are variable and affected individuals are at an increased risk to develop Wilms tumor. Reasons for Referral:Patients with isolated aniridia or clinical features suggestive of WAGR syndrome may be tested for deletions of 11p13 by FISH simultaneously with high-resolution chromosomal analysis (if not previously performed). Approximately 20-30% of patients with aniridia will have an abnormality of 11p detectable by high-resolution chromosome studies. 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 aniridia/WAGR syndrome is performed on metaphase chromosomes. Our laboratory uses a panel of 4 FISH probes that span the region of WT1 and PAX 6. The presence of a single hybridization signal for any of the probes indicates a deletion of that region. The majority of patients with WAGR will be deleted with one or more of these probes. If an affected individual is found to be deleted for the WT1 (Wilms tumor) probe, they will need to be monitored for the development of Wilms tumor. The probability of a deletion being detected for patients with isolated aniridia is lower. Patients with isolated aniridia and a negative FISH test may have a mutation in PAX 6 not detectable by this assay. 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, 88271x3, 88273, 88280, 88291 References:1. Crolla J, et al. (2002) Am. J. Hum. Genet. 71: 1138-1149. Forms: >> Cytogenetics
Requisition Test Code:8450 |