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Retinoblastoma via the RB1 Gene

Summary and Pricing

Test Method

Sequencing and CNV Detection via NextGen Sequencing using PG-Select Capture Probes
Test Code Test Copy GenesTest CPT Code Gene CPT Codes Copy CPT Codes Base Price
4501 RB1 81479 81479,81479 $640 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
4501RB181479 81479,81479 $640 Order Options and Pricing

Pricing Comments

This test is also offered via our exome backbone with CNV detection (click here). The exome-based test may be higher priced, but permits reflex to the entire exome or to any other set of clinically relevant genes.

An additional 25% charge will be applied to STAT orders. STAT orders are prioritized throughout the testing process.

Turnaround Time

18 days on average for standard orders or 13 days on average for STAT orders.

Please note: Once the testing process begins, an Estimated Report Date (ERD) range will be displayed in the portal. This is the most accurate prediction of when your report will be complete and may differ from the average TAT published on our website. About 85% of our tests will be reported within or before the ERD range. We will notify you of significant delays or holds which will impact the ERD. Learn more about turnaround times here.

Targeted Testing

For ordering sequencing of targeted known variants, go to our Targeted Variants page.

EMAIL CONTACTS

Genetic Counselors

Geneticist

  • Hannah Cox, PhD

Clinical Features and Genetics

Clinical Features

Retinoblastoma (RB) is the most common intraocular cancer in childhood, with onset usually before five years of age. Incidence is one case per 15,000-20,000 livebirths worldwide. The most common presenting sign of RB is a white pupillary reflex (leukocoria), which reflects light (e.g., photographic flash) and blocks view of the red retina. Heritable retinoblastoma presents at a younger age than does nonheritable disease (Dimaras et al. Lancet 379(9824):1436-46, 2012). Approximately 40% of patients affected with RB are affected unilaterally and 60% of patients bilaterally. Children with germline RB1 variants are also at a risk of pinealomas which occur in the pineal gland of the brain. Other cancers which typically occur later adolescent or adult life are osteosarcomas, soft tissue sarcomas, or melanomas (Lohmann and Gallie. GeneReviews. 2010).

Genetics

Retinoblastoma is caused by variants in the RB1 gene, which is a tumor suppressor that is involved in cell cycle regulation (G1 to S phase; Lohmann and Gallie. GeneReviews. 2010). The pRB protein is phosphorylated by a cyclin-dependent kinase complex. Upon phosphorylation, the binding activity of the pocket domain is lost, resulting in the release of cellular proteins involved in cell cycle progression. Most variants lead to complete nonfunctional pRB activity leading to faulty cell cycle arrest upon cellular stresses; however, some variants have residual activity which can lead to low-penetrance retinoblastoma (Bremner et al. Am J Hum Genet 61:556–70, 1997). Most variants are specific to families, suggesting a high rate of variants at the RB1 locus and usually through the paternal germline (Dimaras et al. Lancet 379(9824):1436-46, 2012). An inherited mutated copy of RB1 predisposes a child to ocular cancer and loss of the other allele is involved in the progression to retinoblastoma along with other cancer pathways.

Clinical Sensitivity - Sequencing with CNV PG-Select

Overall clinical sensitivity using molecular analysis of the RB1 gene is approximately 95% (Rushlow et al. Hum Mutat 30: 842–51, 2009). About 75% of cases are caused by single nucleotide changes and small indels, which can readily be detected by sequencing. About 10% of cases are due to hypermethylation of the RB1 promoter and will not be detected by sequencing (Lohmann and Gallie. GeneReviews. 2010). Gross deletions and duplications occur in up to 16% of RB1 variants. Approximately 10-12% variants are due to hypermethylation of the RB1 promoter and will not be detected by deletion and duplication analysis (Lohmann and Gallie. GeneReviews. 2010).

Testing Strategy

This test provides full coverage of all coding exons of the RB1 gene, plus ~10 bases of flanking noncoding DNA. We define full coverage as >20X NGS reads or Sanger sequencing.

Indications for Test

Individuals with a clinical presentation of retinoblastoma, especially bilateral ocular tumors or a family history of retinoblastoma. Individuals with unilateral retinoblastoma and no family history should also be tested. This test is specifically designed for heritable germline variants and is not appropriate for the detection of somatic variants in tumor tissue.

Gene

Official Gene Symbol OMIM ID
RB1 614041
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Disease

Name Inheritance OMIM ID
Retinoblastoma AD 180200

Related Test

Name
Melanoma Panel

Citations

  • Bremner et al. (1997). "Deletion of RB exons 24 and 25 causes low-penetrance retinoblastoma." Am J Hum Genet 61:556–70. PubMed ID: 9326321
  • Dimaras et al. (2012). "Retinoblastoma." Lancet 379(9824):1436-46. PubMed ID: 22414599
  • Lohmann and Gallie. GeneReviews. 2010
  • Lohmann and Gallie. GeneReviews. 2010. PubMed ID: 20301625
  • Rushlow et al. (2009). "Detection of mosaic RB1 mutations in families with retinoblastoma." Hum Mutat 30: 842–51. PubMed ID: 19280657

Ordering/Specimens

Ordering Options

We offer several options when ordering sequencing tests. For more information on these options, see our Ordering Instructions page. To view available options, click on the Order Options button within the test description.

myPrevent - Online Ordering

  • The test can be added to your online orders in the Summary and Pricing section.
  • Once the test has been added log in to myPrevent to fill out an online requisition form.
  • PGnome sequencing panels can be ordered via the myPrevent portal only at this time.

Requisition Form

  • A completed requisition form must accompany all specimens.
  • Billing information along with specimen and shipping instructions are within the requisition form.
  • All testing must be ordered by a qualified healthcare provider.

For Requisition Forms, visit our Forms page


Specimen Types

Specimen Requirements and Shipping Details

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ORDER OPTIONS

View Ordering Instructions

1) Select Test Method (Backbone)


1) Select Test Type


2) Select Additional Test Options

STAT and Prenatal Test Options are not available with Patient Plus.

No Additional Test Options are available for this test.

Note: acceptable specimen types are whole blood and DNA from whole blood only.
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