Achromatopsia 6 or Retinal Cone Dystrophy 3 via the PDE6H Gene
Summary and Pricing
Test Method
Exome Sequencing with CNV DetectionTest Code | Test Copy Genes | Test CPT Code | Gene CPT Codes Copy CPT Code | Base Price | |
---|---|---|---|---|---|
7961 | PDE6H | 81479 | 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.
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.
Clinical Features and Genetics
Clinical Features
Achromatopsia is a congenital cone rod dystrophy (CRD) that can be distinguished from other CRDs on the basis of primary cone involvement, stationary course, and normal fundus (Hamel. 2007. PubMed ID: 17270046). Two clinical types of achromatopsia, complete and incomplete, are recognized. In patients with complete achromatopsia, symptoms usually begin in infancy and include nystagmus, low visual acuity, photophobia, severe color vision defects, and selective absence of functioning cone photoreceptor cells in electroretinogram (ERG) findings. Patients with incomplete achromatopsia retain residual functioning cone cells. In addition, they have mild visual acuity and mild color vision defects. The prevalence of complete achromatopsia is 1 per 30,000 people worldwide (Michaelides et al. 2004. PubMed ID: 14736794). However, in Micronesian atoll of Pingelap, achromatopsia affects ~5% of the island population (Morton et al. 1972. PubMed ID: 4537352).
PDE6H-associated retinal disorder is characterized as cone dystrophy with nyctalopia and supernormal rod responses (Piri et al. 2005. PubMed ID: 15629837).
Genetics
Achromatopsia is a heterogeneous genetic disease that is inherited in an autosomal recessive manner. It is caused by defects in various genes that encode important elements of the cone phototransduction process (Chang et al. 2009. PubMed ID: 19887631; Thiadens et al. 2009. PubMed ID: 19615668). PDE6H encodes the inhibitory γ-subunit of cone-specific cyclic guanosine monophosphate (cGMP)-phosphodiesterase (PDE) (Piri. 2005. PubMed ID: 15629837). To date, less than 5 PDE6H causative variants (nonsense) have been reported (Human Gene Mutation Database).
Clinical Sensitivity - Sequencing with CNV PGxome
Due to genetic heterogeneity and the limited number of reported cases, the clinical sensitivity of PDE6H for cone disorders is not precisely known. However, pathogenic variants in PDE6H appear to be a rare cause of retinal disorders. So far, large deletions/duplications have not been documented in this gene (Human Gene Mutation Database).
Testing Strategy
This test provides full coverage of all coding exons of the PDE6H 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
Patients with normal rod response and absence of cone response in ERG findings, and no pathogenic variants in the CNGB3, CNGA3 and GNAT2 genes (Kohl et al. 2016). This test may also be considered for the reproductive partners of carriers of PDE6H pathogenic variants.
Patients with normal rod response and absence of cone response in ERG findings, and no pathogenic variants in the CNGB3, CNGA3 and GNAT2 genes (Kohl et al. 2016). This test may also be considered for the reproductive partners of carriers of PDE6H pathogenic variants.
Gene
Official Gene Symbol | OMIM ID |
---|---|
PDE6H | 601190 |
Inheritance | Abbreviation |
---|---|
Autosomal Dominant | AD |
Autosomal Recessive | AR |
X-Linked | XL |
Mitochondrial | MT |
Disease
Name | Inheritance | OMIM ID |
---|---|---|
Retinal Cone Dystrophy 3A | AR | 610024 |
Related Test
Name |
---|
Leber Congenital Amaurosis Panel |
Citations
- Chang et al. 2009. PubMed ID: 19887631
- Hamel. 2007. PubMed ID: 17270046
- Human Gene Mutation Database (Bio-base).
- Kohl et al. 2016. PubMed ID: 20301591
- Michaelides et al. 2004. PubMed ID: 14736794
- Morton et al. 1972. PubMed ID: 4537352
- Piri et al. 2005. PubMed ID: 15629837
- Thiadens et al. 2009. PubMed ID: 19615668
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
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
ORDER OPTIONS
View Ordering Instructions1) Select Test Type
2) Select Additional Test Options
No Additional Test Options are available for this test.