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HelpTest Code LAB1850 Gaucher DNA Sequencing
Clinical System Name
Gaucher (GBA) DNA Analysis
Description
The Seattle Children's Hospital Molecular Laboratory offers different options for Gaucher DNA Analysis:
- Gaucher Disease full gene sequencing - Sequencing of all 11 exons and their flanking regions will detect greater than 98% of variants in individuals affected with Gaucher disease. This test is primarily used for genotyping confirmed cases or as a secondary confirmation of diagnosis. Sequencing can also be used for carrier testing.
- Gaucher Disease 11 Variant Panel - This 11 variant panel includes: N370S, L444P, 84GG, IVS2+1g>a, V394L, D409H, D409V, R463C, R463H, R496H, 55-bp deletion (exon9). This test is used to provide additional information regarding diagnosed patients, provide carrier testing for at-risk family members or general population screening. Detection rate is 96% in Ashkenazi Jewish population and 70% in non-Ashkenazi Jewish population, on average.
- Targeted Gene Variant Sequencing (LAB1915) - For targeted analysis of variants previously identified through clinical testing of a family member or research testing of the individual. Please review requirements and restrictions for testing.
Sample Requirements
Note: For patients who have had a whole blood transfusion, wait 10 days post transfusion to draw for genetic testing. No wait time is necessary for blood or saliva collection if the patient received leuko-reduced red cells or plasma.
Specimen: Whole blood, cord blood
Container(s): Lavender/EDTA, Yellow/ACD A or B
Preferred Vol: 3 mL
Minimum Vol: 1 mL
Note: Heparin samples (Green tops) are unacceptable.
Specimen: Extracted DNA from EDTA blood
Minimum: 10µg
Note: Isolation of nucleic acids for clinical testing must be performed in a CLIA-certified
laboratory or a laboratory meeting equivalent requirements as determined by the CAP
and/or the CMS. DNA concentration minimum 50 µg/mL; 260/280 ratio 1.70-2.00.
Specimen: Cultured cells
Acceptable: Fibroblasts
Container(s): T-25 flasks
Preferred Vol: 2 flasks
Processing Instructions
Reject due to: Heparin
Spin: No
Aliquot: No
Temp: Refrigerate
Storage location: Molecular Genetics box in CPA refrigerator #2
Off-site collection: Refrigerate blood samples until ready to ship. Transport all sample types at room temperature via overnight shipping.
Stability
| Specimen Type | Temperature | Time |
|---|---|---|
| Cultured cells | Room temp | 3 days |
| Whole blood, extracted DNA | Room temp | 3-5 days |
| Whole blood, extracted DNA | Refrigerated | 7 days |
| Extracted DNA | Frozen | ok |
Note: Whole blood samples > 7days may be submitted to be assessed by our lab for acceptability for testing.
Availability
| STAT | Performed | TAT |
|---|---|---|
| Contact lab | Monday - Friday | 2-3 weeks |
Performing Laboratory
Seattle Children's Laboratory
Department
Department: Molecular Genetics Laboratory
Phone: 206-987-3872
Lab Client Services: 206-987-2617
Lab Genetic Counselor: LabGC@seattlechildrens.org
CPT Codes
| Gaucher Full Gene Sequencing | 81479 |
| Gaucher 11 Mutation Panel | 81251 |
| Gaucher Targeted Variant Analysis | 81403 |
Methodology
Method:
Full gene sequencing - bi-directional sequencing of all 11 exons and exon-intron boundaries
11 Mutation Panel and Targeted Variant - bi-directional sequencing of targeted variants
Limitations: Mutations in the promoter region, large deletions, large duplications, or rare recombinant mutations may not be detected by this method.
Reference Range
Interpretive report will be provided
Requisition
Special Instructions
Links to: Gaucher Disease GeneReview
Clinical Utility
Gaucher disease type I is a treatable lysosomal storage disease leading to hepatosplenomegaly, anemia and thrombocytopenia, and skeletal involvement including osteoporosis, osteonecrosis, lytic lesions and Erlenmeyer flask deformity. Gaucher disease type II presents in infancy with severe neurologic and visceral involvement but without skeletal manifestations. Type III presents as Type I but with the addition of neurologic involvement. Inheritance is autosomal recessive. Type I Gaucher is common in the Ashkenazi Jewish population, with a prevalence of 1/450 – 1/1000.