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HelpTest Code RB1 Eval RB1 Gene Evaluation
Clinical System Name
RB1 Gene Evaluation
Synonyms
Retinoblastoma
Sample Requirements
Specimen: Whole Blood
Container(s): 2 Lavender/EDTA
Preferred Vol: 4.0 mL per Lavender/EDTA tube ~8mL total
Minimum Vol: Infants/newborn: 2 EDTA tube (lavender top) of blood – approximately 1-2 mL per tube
Specimen: DNA
Container(s): Sterile plastic tube
Preferred Vol: 5-10 mcg at min volume 50 microliters
Minimum Vol:
Notes: Please include the concentration.
Notes: Signed informed consent is required.
Processing Instructions
Reject due to:
Spin: N
Aliquot: N
Temp: 2-8 C
Storage location: Affix large Cerner labels to tubes and place in refrigerator send-outs rack.
Off-site collection: Send whole blood refrigerated.
Stability
| Specimen Type | Temperature | Time |
|---|---|---|
| Whole blood | Room temp | 3 d |
| Whole blood | Refrigerated | 7 d |
| Whole blood | Frozen | N |
| Extracted DNA | Room temp | 3-4 d |
| Extracted DNA | Refrigerated | 1 y |
| Extracted DNA | Frozen | Indefinitely |
Availability
| STAT | TAT |
|---|---|
| N | 6-8 w |
Performing Laboratory
Genetic Diagnostic Laboratory, University of Pennsylvania School of Medicine
Department: Genetic Diagnostic Laboratory, University of Pennsylvania School of Medicine, 415 Anatomy-Chemistry Building, 3620 Hamilton Walk, Philadelphia, PA 19104
Phone Number: (215) 573-9161
Department
Department: Send Outs/Genetic
Phone Number: (206) 987-2563
Methodology
Method:
Sequencing: Sanger sequencing of all coding exons and flanking intronic regions of RB1 gene
Deletion/Duplication (Blood): A custom comparative genomic hybridization and single nucleotide polymorphism (CGH + SNP) array designed using Agilent technologies. This high-density array is designed to detect exonic and intronic copy number changes as small as 400 bp and 1.5kb, respectively, in the targeted gene(s). The analysis of the array hybridization data for targeted gene(s) is performed using Cytogenomics software (Agilent Technologies). These results may be confirmed by qPCR.
Note: If a copy number variation occurs that involves the terminal end of the RB1 gene, this assay will expand the analysis to chromosome 13q in order to define breakpoints occurring outside the targeted gene.
Analytical Volume:
Limitations:
Reference Range
Interpretive report is provided. The probability that a RB1 gene mutation will be detected in an index case depends upon whether the tumor is unilateral or bilateral, unifocal or multi-focal, whether we test tumor or blood, and whether the family history is positive or negative for disease. The sensitivity for bilateral retinoblastoma is ~94% for a germline mutation to be detected. Tumor analysis is recommended for individuals with a personal history of unilateral retinoblastoma and when the tumor tissue is available. Deep intronic mutations (non-coding sequences) might not be detected with sequencing.
Send Out Instructions
| Reference Test Name: |
Retinoblastoma: Sequence analysis with reflex to deletion/duplication analysis [Blood]
|
| Reference Test Number: | None specified |
| Instructions: | Ship ambient via FedEx. Samples are received Monday - Friday AM. U Penn does NOT accept Saturday delivery. If sample is drawn on a Friday, please refrigerate it until shipment on the following business day. Keep a copy of the requisition for our records. |
Description
Retinoblastoma is a malignant tumor of the developing retina that occurs in children, usually before the age of five years. Retinoblastoma may be unilateral or bilateral. Approximately 60% of patients have unilateral RB with a mean age at diagnosis of 24 months; approximately 40% of patients have bilateral RB with a mean age at diagnosis of 15 months. Germline mutations in the RB1 gene (chromosomal location 13q14) predispose individuals to retinoblastoma and increase the risk of developing other non-ocular tumors.
Special Instructions
Links to:
Genetic Diagnostic Laboratory, University of Pennsylvania School of Medicine