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| The Kleberg Cytogenetics Laboratory offers a fluorescence in situ hybridization (FISH)-based assay for identifying the deletion of the distal short arm of the X chromosome associated with Kallmann syndrome. Clinical Features:The features of X-linked Kallmann syndrome primarily include hypogonadotropic hypogonadism and anosmia (inability to smell), however the phenotype is variable. Some males have large deletions of Xp22.3 and manifest several clinical features including Kallmann syndrome and ichthyosis (steroid sulfatase deficiency). Reasons for Referral:Patients with clinical features suggestive of X-linked Kallmann syndrome may be tested for deletions of Xp22.3 by FISH. Carrier testing is available for female relatives if the affected male has been tested previously in our laboratory and has been shown to have a deletion. 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 or in cases of extremely low or absent unconjugated estriol on a maternal serum screen (performed in conjunction with FISH for STS deficiency). 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 Kallmann syndrome is performed on metaphase chromosomes using a probe specific for this locus. The absence of a hybridization signal indicates a deletion. Patients with clinical features of both ichthyosis and Kallmann syndrome may have a contiguous gene deletion syndrome that can be identified by using both the Kallmann syndrome FISH probe and the steroid sulfatase gene FISH probe. Individuals with isolated Kallmann syndrome who are not deleted by FISH may have a mutation in the KAL 1 gene or may have an autosomal form of the disorder. 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, 88273, 88271, 88291 References:1. Hou, et al. (1999) J. Formos. Med. Assoc. 6: 448-451. Forms: >> Cytogenetics
Requisition Test Code:8469 |