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Cone-Rod Dystrophy via the CABP4 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
CABP4 81479 81479,81479 $990
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
4109CABP481479 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

Cone-rod dystrophy (CORD/CRD) is a rare hereditary retinal disorder with a worldwide prevalence of ~1 in 40,000. CRD is characterized by dysfunction or degeneration of cone photoreceptors with relative preservation of rod function in the initial stages. The most common symptoms are photophobia and epiphora in bright light, decreased visual acuity, and dyschromatopsia. Fundus changes may vary from mild pigment granularity to a distinct atrophic lesion in the central macula. As the disease progresses, degeneration of rod photoreceptors also occurs and leads to progressive night blindness and peripheral visual field loss (Hamel 2007).


Non syndromic CRD is genetically heterogeneous and exhibits autosomal dominant (ad), autosomal recessive (ar) and, rarely, X-linked (xl) inheritance (Hamel 2007). So far, about 25 genes have been implicated in different forms of CRD (RetNet). One of the causative genes, CABP4, encodes the neuronal Ca2+-binding protein, which is expressed in the retina and in the cochlea. CABP4 is shown to be essential for calcium influx and neurotransmitter release in the synaptic terminal of the photoreceptors (Maeda et al. 2005; Haeseleer et al. 2004; Littink et al. 2008). Dysfunctional CABP4 is reported to influence the cone function more than rod function (Littink et al. 2008). The patients carrying CABP4 gene mutations did not experience night blindness. The phenotype was classified as congenital cone–rod synaptic disorder (Littink et al. 2008). Mutations in CABP4 have also been shown to cause autosomal recessive congenital stationary night blindness (arCSNB) (Zeitz et al. 2006). Thus far, ~ 5 pathogenic sequence variations have been reported in CABP4 that resulted in congenital cone–rod synaptic disorder, Leber’s congenital amaurosis (LCA)-like phenotype and arCSNB (Littink et al. 2008; Aldahmesh et al. 2010; Zeitz et al. 2006; Human Gene Mutation Database).

Clinical Sensitivity - Sequencing with CNV PGxome

A mutation analysis in pedigrees of two families with arCSNB, who did not carry mutations in CACNA1F gene, detected homozygous and compound heterozygous CABP4 mutations in all three affected individuals. Seven unaffected family members were heterozygous for CABP4 mutations. These mutations were absent in over 220 control alleles (Zeitz et al. 2006). Another molecular analysis in a consanguineous family with LCA-like phenotype identified a homozygous single base-pair insertion in all four siblings, while the parents and an unaffected sibling were heterozygous for this mutation (Aldahmesh et al. 2010). Another study identified a novel homozygous nonsense mutation in CABP4 in two siblings diagnosed with a congenital cone–rod synaptic disorder phenotype. The parents were heterozygous for this mutation, and the mutation was not found in 300 alleles of ethnically matched control individuals (Littink et al. 2008).

Testing Strategy

This test provides full coverage of all coding exons of the CABP4 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 CRD and arCSNB. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in CABP4.


Official Gene Symbol OMIM ID
CABP4 608965
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


Name Inheritance OMIM ID
Night Blindness, Congenital Stationary, Type 2B AR 610427

Related Tests

Cone-Rod Dystrophy Panel
Leber Congenital Amaurosis Panel


  • Aldahmesh MA, Al-Owain M, Alqahtani F, Hazzaa S, Alkuraya FS. 2010. A null mutation in CABP4 causes Leber’s congenital amaurosis-like phenotype. Molecular vision 16: 207. PubMed ID: 20157620
  • Haeseleer F, Imanishi Y, Maeda T, Possin DE, Maeda A, Lee A, Rieke F, Palczewski K. 2004. Essential role of Ca2+-binding protein 4, a Cav1.4 channel regulator, in photoreceptor synaptic function. Nat Neurosci. 7:1079-1087. PubMed ID: 15452577
  • Hamel CP. 2007. Cone rod dystrophies. Orphanet J Rare Dis 1;2:7. PubMed ID: 17270046
  • Human Gene Mutation Database (Bio-base).
  • Littink KW, Genderen MM van, Collin RWJ, Roosing S, Brouwer APM de, Riemslag FCC, Venselaar H, Thiadens AAHJ, Hoyng CB, Rohrschneider K, Hollander AI den, Cremers FPM, et al. 2008. A Novel Homozygous Nonsense Mutation in CABP4 Causes Congenital Cone-Rod Synaptic Disorder. Investigative Ophthalmology & Visual Science 50: 2344–2350. PubMed ID: 19074807
  • Maeda T, Lem J, Palczewski K, Haeseleer F. 2005. A critical role of CaBP4 in the cone synapse. Investigative ophthalmology & visual science 46: 4320–4327. PubMed ID: 16249514
  • Zeitz C, Kloeckener-Gruissem B, Forster U, Kohl S, Magyar I, Wissinger B, Matyas G, Borruat F-X, Schorderet DF, Zrenner E, Munier FL, Berger W. 2006. Mutations in CABP4, the Gene Encoding the Ca2+-Binding Protein 4, Cause Autosomal Recessive Night Blindness. Am J Hum Genet 79: 657–667. PubMed ID: 16960802


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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