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Cone-Rod Dystrophy via the CACNA2D4 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
CACNA2D4 81479 81479,81479 $990
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
11129CACNA2D481479 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 CACNA2D4 encodes a voltage-gated L-type calcium channel auxiliary subunit and is mostly expressed in the retina (Postel et al. 2013; Wycisk 2006). Mouse model studies have shown that the mutations in CACNA2D4 result in profound loss of retinal signal transmission and an abnormal morphology of ribbon synapses in photoreceptors (Wycisk 2006). A mutation in its human orthologue, CACNA2D4, has been shown to cause autosomal recessive cone dystrophy. Thus far, only a nonsense mutation in CACNA2D4 has been reported to be causative for arCRD (Wycisk et al. 2006). A gross deletion in CACNA2D4 has been reported to result in psychiatric diseases in general and Bipolar disorder in particular (Van Den Bossche et al. 2012; Human Gene Mutation Database).

Clinical Sensitivity - Sequencing with CNV PGxome

A CACNA2D4 mutation analysis in a pedigree of an index patient diagnosed with cone dystrophy detected a homozygous c.2406C>A substitution (p.Tyr802*) in the index patient and in an affected sibling, whereas unaffected father was heterozygous for this mutation. This mutation was absent in the index patient's unaffected siblings and in over 224 control chromosomes (Wycisk et al. 2006).

Testing Strategy

This test provides full coverage of all coding exons of the CACNA2D4 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. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in CACNA2D4.


Official Gene Symbol OMIM ID
CACNA2D4 608171
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


Name Inheritance OMIM ID
Retinal Cone Dystrophy 4 AR 610478


  • Den Bossche MJ Van, Strazisar M, Bruyne S De, Bervoets C, Lenaerts A-S, Zutter S De, Nordin A, Norrback K-F, Goossens D, Rijk P De, Green EK, Grozeva D, et al. 2012. Identification of a CACNA2D4 deletion in late onset bipolar disorder patients and implications for the involvement of voltage-dependent calcium channels in psychiatric disorders. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics 159B: 465475. PubMed ID: 22488967
  • Hamel CP. 2007. Cone rod dystrophies. Orphanet J Rare Dis 1;2:7. PubMed ID: 17270046
  • Human Gene Mutation Database (Bio-base).
  • Postel K, Bellmann J, Splith V, Ader M. 2013. Analysis of cell surface markers specific for transplantable rod photoreceptors. Molecular vision 19: 2058. PubMed ID: 24146539
  • Wycisk KA, Zeitz C, Feil S, Wittmer M, Forster U, Neidhardt J, Wissinger B, Zrenner E, Wilke R, Kohl S. 2006. Mutation in the Auxiliary Calcium-Channel Subunit CACNA2D4 Causes Autosomal Recessive Cone Dystrophy. The American Journal of Human Genetics 79: 973977. PubMed ID: 17033974
  • Wycisk KA. 2006. Structural and Functional Abnormalities of Retinal Ribbon Synapses due to Cacna2d4 Mutation. Investigative Ophthalmology & Visual Science 47: 35233530. PubMed ID: 16877424


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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View Ordering Instructions

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2) Select Additional Test Options

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