Test Description:
Angelman syndrome (AS) is a genetic disorder that affects approximately 1 in 15,000 individuals and causes severe developmental delay wtih minimal or no speech. Affected individuals also have a movement or balance disorder presenting as an ataxic gait or tremulous limb movements. Unique behaviors such as frequent laughter and uplifted, flexed arms when walking are common. Microcephaly and seizures are present in most.
Submicroscopic deletions of chromosome 15 (15q11.2) are detected by fluorescence in situ hybridization (FISH). Deletions are identified in approximately 68% of Angelman syndrome patients. Note that a significant portion of patients with Angelman syndrome have no deletion identifiable by FISH on chromosome 15, and may instead have uniparental disomy (UPD) or an imprinting defect. Methylation analysis is recommended to identify patients with UPD or imprinting defects associated with Angelman syndrome. Methylation analysis for Angelman syndrome is clinically available through our DNA Diagnostic Laboratory. Please see this test entry for details and specimen requirements.
Methods:
A FISH probe specific to the 15q11.2 region on chromosome 15 (D15S10) is utilized. At least 50 metaphase cells are analyzed for deletion detection. We are also able to detect duplications for this locus, which are associated with autism in some individuals. This test was developed and its performance characteristics determined by Vysis, IL as required by the CLIA 1988 regulations. Our laboratory has established and verified the test’s accuracy and precision. It has not been cleared or approved for specific uses by the U.S. Food and Drug Administration. However, the FDA has determined that such clearance is not necessary to use this test for clinical purposes.
Specimen Requirements:
7 cc of whole blood in sodium heparinized vacutainer (green top tube). Other specimens can also be tested. Please contact the laboratory at (517) 353-2032 or 1-877-TEST-DNA for more information regarding specimen requirements for non-blood samples.
Shipping Instructions:
Ship immediately or via overnight delivery at room temperature to the MSU Cytogenetics Laboratory, B123 Life Sciences Bldg, East Lansing, MI 48824. For specimen transport, call 517-353-2032 or 1-877-TEST-DNA. For specimens obtained on the weekend, call our pager at 517-229-6130. Please leave a return phone number and our weekend staff will contact you.
Turnaround Time: 7 days
Test CPT Codes: 88271, 88273, 88291