Prader-Willi syndrome, Deletion 15q11.2, SNRPN, FISH, for Genetic Diagnosis

Prader-Willi syndrome, Deletion 15q11.2, SNRPN, FISH, for Genetic Diagnosis
WSLH Department: Cytogenetics
WSLH Test Code:871F30
Includes:FISH analysis of 10 cells for deletion of the SNRPN gene in 15q11.2
Methodology:**(CPT Codes: 88271, 88273)** Fluorescence in situ hybridization performed on metaphase cells using DNA probes (LSI Prader-Willi/Angelman Region SNRPN, dual color; Vysis, Inc) specific for 15q11.2 (SNRPN), simultaneously with a probe for 15p11.2 (D15Z1) in the short arm of chromosome 15 and a probe for 15q22 (PML) as controls.
Availability:Monday-Friday 7:45 AM - 4:30 PM, Saturday 7:45 AM - 12:00 PM
Turn-around Time:Approximately 10-14 days, (Reports are issued Monday-Friday 7:45 AM - 4:30 PM)
Recommended Uses:Detection of deletion 15q11.2 associated with Prader-Willi syndrome; phenotypic features include obesity, food seeking behaviors, infantile hypotonia and failure to thrive, developmental delay.
Contraindications: 
Specimen Requirements:1-2 ml whole blood collected in sodium heparin vacuum type tube
Collection Kit/Container: 
Patient Preparation: 
Collection Instructions:Draw blood using aseptic techniques into a sterile sodium heparin vacuum type tube. Invert tube to mix. If using larger tubes, draw full tube of blood to avoid over-treatment with anti-coagulant.
Specimen Handling and Transport:Store and transport specimens at room temperature (may transport with coolant during hot, >85 degrees, weather). Specimens must be received by the laboratory within 24 hours of collection.
Unacceptable Conditions:Blood that is collected in EDTA, sodium citrate, or other anti-coagulants is not acceptable. Blood that is clotted or hemolyzed is not acceptable. Blood must not be frozen. Plasma and serum are not acceptable.
Requisition Form:Cytogenetics Lab Genetic Diagnosis Form #131
Required Information:Laboratory regulations require the following minimum information to be provided on the requisition form for a specimen to be accepted for testing: Patient name or unique identifier; date and time of collection, patient date of birth and sex, specimen type/site of collection, test request(s), reason for referral, clinician name and UPIN/NPI, and address for reporting results. Please be certain that name/identifier on the form matches that on the specimen label.
Results include:Deletion 15q11.2 detected/not detected. Karyotype written using International System for Human Cytogenetic Nomenclature (ISCN) 2013 and interpretation of results.
Limitations:Very small deletions, point mutations, uniparental disomy, and imprinting abnormalities are not detected by this assay. Negative FISH results do not rule out a diagnosis of Prader-Willi syndrome.
Additional Tests Recommended:Methylation specific PCR is recommended as the primary test for Prader-Willi syndrome with FISH used to follow-up abnormal results to differentiate between deletion and uniparental disomy/imprinting abnormalities. Blood chromosome analysis is recommended to look for other causes of the abnormal phenotype. The FISH analysis may be performed as an independent test if chromosome analysis and/or MSPCR was performed previously.
Additional Comments:If FISH assay is not performed in conjunction with chromosome analysis there is an additional charge for processing the specimen.
Additional Tests Performed: 

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