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Familial Exudative Vitreoretinopathy via the RCBTB1 Gene

Summary and Pricing

Test Method

Exome Sequencing with CNV Detection
Test Code Test Copy GenesTest CPT Code Gene CPT Codes Copy CPT Codes Base Price
RCBTB1 81479 81479,81479 $990
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
11867RCBTB181479 81479,81479 $990 Order Options and Pricing

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

Click here for costs to reflex to whole PGxome (if original test is on PGxome Sequencing platform).

Click here for costs to reflex to whole PGnome (if original test is on PGnome Sequencing platform).

Turnaround Time

3 weeks on average for standard orders or 2 weeks 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.


Genetic Counselors


  • Dana Talsness, PhD

Clinical Features and Genetics

Clinical Features

Familial exudative vitreoretinopathy (FEVR) is an inherited ocular disorder characterized by abnormal vascularisation of the peripheral retina. FEVR penetrance is reported to be close to 100%, but shows a variable clinical expression, even within families. At the milder end of the disease spectrum, individuals are asymptomatic or may have a small area of avascularity in the peripheral retina, whereas at the severe end, individuals are legally blind during the first decade of life (Toomes et al. 2004. PubMed ID: 14737064). The secondary retinal pathologies include retinal folds and detachment in association with retinal traction, subretinal or intraretinal exudation, and fibrovascular proliferation at the junction between vascularised and non-vascularised retina. Rarely, retinoschisis and giant retinal tears have been reported (Toomes and Downey 2011. PubMed ID: 20301326).


FEVR has been linked to five different loci (EVR1 to EVR5). EVR1, EVR3 and EVR4 are located on 11q13–23; EVR2 is on the X-chromosome and EVR5 is on chromosome 7. The EVR4 locus has been reported as extremely rich in genes that are associated with a range of retinal disorders like Best disease (BEST1), oculocutaneous albinism (TYR), retinitis pigmentosa (ROM1), Usher’s syndrome (MYO7A), Bardet Biedel syndrome (BBS1) and inflammatory vitreoretinopathy (CAPN5) (Bamashmus et al. 2000. PubMed ID: 10729291; Toomes et al. 2004. PubMed ID: 15024691).

FEVR is genetically heterogeneous and exhibits autosomal dominant (AD), autosomal recessive (AR) and X-linked inheritance (XL) with AD being the most common mode. So far, four primary causative genes, LRP5 (low-density lipoprotein 5), FZD4 (frizzled 4), NDP (norrin), and TSPAN12 (tetraspanin-12,) have been identified. The proteins encoded by these genes act as ligand and receptors in the Wnt signaling pathway, which is highly conserved among species and plays an important role in eye organogenesis and angiogenesis (Warden et al. 2007. PubMed ID: 18097984). Together, all four genes are responsible for only 50% of the FEVR cases, indicating the significant genetic heterogeneity of FEVR, and that additional FEVR genes involved in Wnt signaling pathway remain to be identified (Poulter et al. 2010. PubMed ID: 20159112).

Pathogenic variants in RCBTB1 have been implicated in autosomal recessive isolated and syndromic Retinal Dystrophy (Coppieters et al. 2016. PubMed ID: 27486781), autosomal dominant Coats disease, and autosomal dominant familial exudative vitreoretinopathy (Wu et al. 2016. PubMed ID: 26908610). About 5 pathogenic variants RCBTB1 have been reported to be causative (Human Gene Mutation Database). Missense variants have reported in patients with retinal disorders. Of note, pathogenic variants that result in truncated proteins and lead to haploinsufficiency of RCBTB1 have been reported in patients with Coats disease and FEVR (Coppieters et al. 2016. PubMed ID: 27486781; Wu et al. 2016. PubMed ID: 26908610)

Clinical Sensitivity - Sequencing with CNV PGxome

Due to the genetic heterogeneity and limited number of cases, predicting clinical sensitivity is challenging. Analytical sensitivity should be high because all pathogenic variants reported are detectable by sequencing.

Testing Strategy

This test provides full coverage of all coding exons of the RCBTB1 gene plus 10 bases of flanking noncoding DNA in all available transcripts along with other non-coding regions in which pathogenic variants have been identified at PreventionGenetics or reported elsewhere. We define full coverage as >20X NGS reads or Sanger sequencing. PGnome panels typically provide slightly increased coverage over the PGxome equivalent. PGnome sequencing panels have the added benefit of additional analysis and reporting of deep intronic regions (where applicable).

Dependent on the sequencing backbone selected for this testing, discounted reflex testing to any other similar backbone-based test is available (i.e., PGxome panel to whole PGxome; PGnome panel to whole PGnome).

Indications for Test

All patients with symptoms suggestive of familial exudative vitreoretinopathy (FEVR). This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in RCBTB1.


Official Gene Symbol OMIM ID
RCBTB1 607867
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


  • Bamashmus et al. 2000. PubMed ID: 10729291
  • Coppieters et al. 2016. PubMed ID: 27486781
  • Human Gene Mutation Database (Biobase).
  • Poulter et al. 2010. PubMed ID: 20159112
  • Toomes and Downey 2011. PubMed ID: 20301326
  • Toomes et al. 2004. PubMed ID: 14737064
  • Toomes et al. 2004. PubMed ID: 15024691
  • Warden et al. 2007. PubMed ID: 18097984
  • Wu et al. 2016. PubMed ID: 26908610


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

If ordering a Duo or Trio test, the proband and all comparator samples are required to initiate testing. If we do not receive all required samples for the test ordered within 21 days, we will convert the order to the most effective testing strategy with the samples available. Prior authorization and/or billing in place may be impacted by a change in test code.

Specimen Types

Specimen Requirements and Shipping Details

PGxome (Exome) Sequencing Panel

PGnome (Genome) Sequencing Panel

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