DNA icon

Familial Exudative Vitreoretinopathy 1 (FEVR1) via the FZD4 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
FZD4 81479 81479,81479 $990
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
8869FZD481479 81479,81479 $990 Order Options and Pricing

Pricing Comments

Our favored testing approach is exome based NextGen sequencing with CNV analysis. This will allow cost effective reflexing to PGxome or other exome based tests. However, if full gene Sanger sequencing is desired for STAT turnaround time, insurance, or other reasons, please see link below for Test Code, pricing, and turnaround time information. If the Sanger option is selected, CNV detection may be ordered through Test #600.

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).

The Sanger Sequencing method for this test is NY State approved.

For Sanger Sequencing click here.

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; Ober et al. 1980). 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).


FEVR has been linked to five different loci (EVR1 to EVR5). EVR1, EVR3 and EVR4 are located on 11q13–23; EVR2 is on 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; Toomes et al. 2004; Toomes and Downey 2011). 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 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 Wnt signaling pathway, which is highly conserved among species and plays an important role in eye organogenesis and angiogenesis (Warden et al. 2007; Nikopoulos et al. 2010).

FZD4 encoded protein Frizzled 4 is a ligand receptor containing seven transmembrane domains and a cysteine-rich domain (CRD). FZD4 is widely expressed in neurons, endothelial cells, and mural cells of the retinal vasculature (Ye et al. 2009). FZD4 binds to Wnt ligands and activates the Wnt/β-catenin signaling pathway in conjunction with the coreceptors LRP5 and LRP6 (Logan and Nusse 2004; Masckauchán and Kitajewski 2006). NDP encoded Norrin is reported to be a highly specific ligand for FZD4 (Ye et al. 2009: Paes et al. 2011). Together, all the four genes (FZD4, LRP5, NDP and TSPAN12) are responsible for only 50% of the FEVR cases, indicating the significant genetic heterogeneity of FEVR and that additional FEVR genes remain to be identified (Poulter et al. 2010).

So far, about 60 pathogenic variants, mostly missense and nonsense, in FZD4 have been reported to be causative for autosomal dominant FEVR. No gross deletions have been reported in this gene (Human Gene Mutation Database).

Clinical Sensitivity - Sequencing with CNV PGxome

Toomes et al. (2004) reported that together, FZD4 and LRP5 mutations account for 35% of FEVR cases in their familial exudative vitreoretinopathy (FEVR) patient cohort (15% LRP5 and 20% FZD4), (Toomes et al. 2004). A molecular study done in 20 families diagnosed with FEVR identified FZD4 mutations in 8 families (40%), (Boonstra et al. 2009).

Testing Strategy

This test provides full coverage of all coding exons of the FZD4 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), and relatives of patients with known FZD4 mutations.


Official Gene Symbol OMIM ID
FZD4 604579
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


Name Inheritance OMIM ID
Familial Exudative Vitreoretinopathy AD 133780


  • Boonstra F.N. et al. 2009. Investigative Ophthalmology & Visual Science. 50: 4379-85. PubMed ID: 19324841
  • Logan CY, Nusse R. 2004. The Wnt signaling pathway in development and disease. Annu. Rev. Cell Dev. Biol. 20: 781–810. PubMed ID: 15473860
  • Masckauchán TNH, Kitajewski J. 2006. Wnt/Frizzled signaling in the vasculature: new angiogenic factors in sight. Physiology (Bethesda) 21: 181–188. PubMed ID: 16714476
  • Nikopoulos K. et al. 2010. Human Mutation. 31: 656-66. PubMed ID: 20340138
  • Ober RR, Bird AC, Hamilton AM, Sehmi K. 1980. Autosomal dominant exudative vitreoretinopathy. Br J Ophthalmol 64: 112–120. PubMed ID: 7362811
  • Paes KT, Wang E, Henze K, Vogel P, Read R, Suwanichkul A, Kirkpatrick LL, Potter D, Newhouse MM, Rice DS. 2011. Frizzled 4 Is Required for Retinal Angiogenesis and Maintenance of the Blood-Retina Barrier. Investigative Ophthalmology & Visual Science 52: 6452–6461. PubMed ID: 21743011
  • Poulter J.A. et al. 2010. American Journal of Human Genetics. 86: 248-53.  PubMed ID: 20159112
  • Toomes C, Downey L. 2011. Familial Exudative Vitreoretinopathy, Autosomal Dominant. In: Pagon RA, Adam MP, Bird TD, Dolan CR, Fong C-T, Smith RJ, and Stephens K, editors. GeneReviews(®), Seattle (WA): University of Washington, Seattle. PubMed ID: 20301326
  • Toomes C. et al. 2004. American Journal of Human Genetics. 74: 721-30. PubMed ID: 15024691
  • Warden S.M. et al. 2007. Seminars in Ophthalmology. 22: 211-7.  PubMed ID: 18097984
  • Ye X, Wang Y, Cahill H, Yu M, Badea TC, Smallwood PM, Peachey NS, Nathans J. 2009. Norrin, frizzled-4, and Lrp5 signaling in endothelial cells controls a genetic program for retinal vascularization. Cell 139: 285–298. PubMed ID: 19837032


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

loading Loading... ×


An error has occurred while calculating the price. Please try again or contact us for assistance.

View Ordering Instructions

1) Select Test Method (Platform)

1) Select Test Type

2) Select Additional Test Options

No Additional Test Options are available for this test.

Note: acceptable specimen types are whole blood and DNA from whole blood only.
Total Price: loading
Patient Prompt Pay Price: loading
A patient prompt pay discount is available if payment is made by the patient and received prior to the time of reporting.
Show Patient Prompt Pay Price
Copy Text to Clipboard