15q11.2 Duplication, FISH
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Detecting duplications of the 15q11.1-11.3 region in individuals with autistic spectrum disorders
As an adjunct to conventional chromosome analysis to confirm the origin of supernumerary marker chromosomes suspected of being derived from chromosome 15
To help resolve molecular MLPA analysis where 15q duplication is identified, but the structural origin of the duplication is unknown
Genetics Test Information Provides information that may help with selection of the correct test or proper submission of the test request
Useful to identify duplication of chromosome 15 in patients with autism or pervasive developmental delay.
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
Fluorescence In Situ Hybridization (FISH)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
15q11.2 Duplication, FISH
FISH (Fluorescence In Situ Hybridization)
FISH (Fluorescence In Situ Hybridization)
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Provide a reason for referral with each specimen. The laboratory will not reject testing if this information is not provided, but appropriate testing and interpretation may be compromised or delayed.
1. New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (Supply T576) is available in Special Instructions.
2. If not ordering electronically, submit a Cytogenetics/AFP Congenital Disorders Request Form (Supply T238) with the specimen.
Advise Express Mail or equivalent if not on courier service.
Submit only 1 of the following specimens:
Specimen Type: Blood
Container/Tube: Green top (sodium heparin)
Specimen Volume: 5 mL
1. Invert several times to mix blood.
2. Other anticoagulants are not recommended and are harmful to the viability of the cells.
Specimen Type: Amniotic fluid
Container/Tube: Amniotic fluid container
Specimen Volume: 20-25 mL
1. Optimal timing for specimen collection is during 14 to 18 weeks of gestation, but specimens collected at other weeks of gestation are also accepted. Provide gestational age at the time of amniocentesis.
2. Discard the first 2 mL of amniotic fluid.
1. Place the tubes in a Styrofoam container (Supply T329).
2. Fill remaining space with packing material.
3. Unavoidably, about 1% to 2% of mailed-in specimens are not viable.
4. Bloody specimens are undesirable.
5. If the specimen does not grow in culture, you will be notified within 7 days of receipt.
6. Results will be reported and also telephoned or faxed, if requested.
Specimen Type: Chorionic villi
Container/Tube: 15-mL tube containing 15 mL of transport media
Specimen Volume: 20-25 mg
1. Collect specimen by the transabdominal or transcervical method.
2. Transfer chorionic villi to a Petri dish containing transport medium (Supply T095).
3. Using a stereomicroscope and sterile forceps, assess the quality and quantity of the villi and remove any blood clots and maternal decidua.
Specimen Type: Skin biopsy
Container/Tube: Sterile container with sterile Hank's balanced salt solution (Supply T132), Ringer's solution, or normal saline
Specimen Volume: 4 mm diameter
1. Wash biopsy site with an antiseptic soap.
2. Thoroughly rinse area with sterile water.
3. Do not use alcohol or iodine preparations.
4. A local anesthetic may be used.
5. Biopsy specimens are best taken by punch biopsy to include full thickness of dermis.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Amniotic Fluid: 5 mL/Blood: 2 mL/Chorionic Villi: 5 mg/Skin Biopsy: 4 mm
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Cytogenetic abnormalities at the 15q11-q13 locus are reported in up to 4% of patients with autism spectrum disorders. Duplications in this chromosome region can occur as an interstitial tandem repeat or as a supernumerary isodicentric chromosome 15, leading to trisomy or tetrasomy of genes at the 15q11-q13 locus. The majority of interstitial tandem repeats in this region are not detectable by conventional chromosome analysis but can be identified by FISH. Supernumerary chromosomes can often be identified by conventional chromosome analysis but their origin must be confirmed by FISH analysis. Molecular analysis by multiplex ligation-dependent probe amplification (MLPA) can also detect duplications of chromosome 15q, but FISH analysis is necessary to distinguish between interstitial tandem duplication and a supernumerary marker.
The phenotype associated with these abnormalities depends largely on the amount of duplicated material, as well as parent of origin. Small dicentric markers with little 15q material duplicated are often familial and result in a normal phenotype. Larger dicentric 15 markers are usually new mutations and result in mild dysmorphic features, mental retardation, and behavioral abnormalities consistent with autism. Interstitial tandem duplications are associated with autistic spectrum disorders when maternally inherited, but paternally inherited duplications are less likely to cause phenotypic effects.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
An interpretative report will be provided.
Specimens with a normal signal pattern in metaphase and interphase cells are considered negative for this probe.
Specimens with a FISH signal pattern indicating duplication of the critical region (3 signals) will be reported as having a duplication of the region tested by this probe.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Because this FISH assay is not approved by the FDA, it is important to correlate 15q duplications by other established methods, such as clinical history or physical evaluation.
This test is not designed to identify 15q deletions or diagnose Prader-Willi/Angelman syndromes. The most appropriate test to identify 15q deletions or diagnose Prader-Willi/Angelman syndromes is PWDNA/81153 Prader-Willi/Angelman Syndrome, Molecular Analysis.
(Clinical pathologic correlative studies.)
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Mao R, Jalal SM, Snow K, et al: Characteristics of two cases with dup(15)(q11.2-q12): one of maternal and one of paternal origin. Genet Med 2000;2:131-135
2. Thomas JA, Johnson J, Peterson Kraai TL, et al: Genetic and clinical characterization of patients with an interstitial duplication 15q11-q13, emphasizing behavioral phenotype and response to treatment. Am J Med Genet 2003;119:111-120
3. Battaglia A: The inv dup(15) or idic(15) syndrome: a clinically recognizable neurogenetic disorder. Brain Dev 2005;5:365-369
4. Muhle R, Trentacoste S, Rapin I: The genetics of autism. Pediatrics 2004;113:472-486
Method Description Describes how the test is performed and provides a method-specific reference
This FISH test involves 2 commercially available DNA probes (D51S10 and SNRPN) and analysis is performed on metaphase cells and interphase nuclei. Analysis of metaphase cells is performed to determine whether the 15q duplication is the result of an interstitial duplication or a supernumerary dicentric marker. Since tandem 15q duplications of SNRPN may be difficult to detect on metaphase cells, interphase nuclei are scored to identify duplications, which are represented by the observation of 3 target probe signals. (Unpublished Mayo data)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Samples processed Monday through Sunday. Results reported Monday through Friday, 8 a.m.-5 p.m. CST.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
This test was developed using an analyte specific reagent. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
88271 x 2-DNA probe, each
88273-Chromosomal in situ hybridization
88291-Interpretation and report
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
|Result ID||Reporting Name||LOINC Code|
|G_481||Reason For Referral||42349-1|
|30147||Reveiwed By||In Process|