Cataract Type 2 (CTRCT2) via the CRYGC 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 | |
---|---|---|---|---|---|
3891 | CRYGC | 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
Cataracts are described as opacification of the crystalline lens of the eye that result in abnormal refraction index and light scattering. Congenital cataracts (CC) are a serious and leading cause of reversible blindness in childhood. They account for one-tenth of the cases of childhood blindness (Francis and Moore 2004). Estimated prevalence rate is 1.2 - 6.0 per 10,000 live births. Early diagnosis and surgery and optical correction have resulted in an improved outcome for infants with either unilateral or bilateral cataracts (Lambert and Drack 1996). CRYGC-associated cataracts (CTRCT2) has been described as multiple types such as Coppock-like cataract, aculeiform cataract and nuclear cataracts (Héon et al. 1999; Lubsen et al. 1987).
Genetics
CTRCT2 is an autosomal dominant disorder that is caused by pathogenic sequence variants in the crystallin, gamma-C (CRYGC) gene, which is located on chromosome 2q33-35 (Héon et al. 1999; Lubsen et al. 1987). In a four-generation Chinese family with six nuclear cataracts and microcornea, affected members found to have a causative variant in CRYGC (Zhang et al. 2009). The CRYGC gene encoded structural protein gamma-crystallin plays an important role in the maintenance of lens transparency and refractive index (Graw 1999). To date, over 10 pathogenic CRYGC sequence variants have been reported, which are mostly missense and nonsense (Human Gene Mutation Database).
Clinical Sensitivity - Sequencing with CNV PGxome
In the Santhiya et al. study (2002), seven families with non-syndromic, autosomal dominant congenital cataracts were screened for pathogenic variants in genes encoding γ-crystallins (CRYG). In three families, pathogenic variants were identified. One of the families had a causative variant in CRYGC (Santhiya et al. 2002).
Testing Strategy
This test provides full coverage of all coding exons of the CRYGC 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
The ideal CRYGC test candidates are individuals who present with autosomal dominant congenital cataract.
The ideal CRYGC test candidates are individuals who present with autosomal dominant congenital cataract.
Gene
Official Gene Symbol | OMIM ID |
---|---|
CRYGC | 123680 |
Inheritance | Abbreviation |
---|---|
Autosomal Dominant | AD |
Autosomal Recessive | AR |
X-Linked | XL |
Mitochondrial | MT |
Disease
Name | Inheritance | OMIM ID |
---|---|---|
Cataract 2 | AD | 604307 |
Related Test
Name |
---|
Congenital Cataracts Panel |
Citations
- Francis P.J., Moore A.T. 2004. Current opinion in ophthalmology. 15: 10-5. PubMed ID: 14743013
- Graw J. 1999. Progress in Retinal and Eye Research. 18: 235-67. PubMed ID: 9932285
- Héon E. et al. 1999. American Journal of Human Genetics. 65: 1261-7. PubMed ID: 10521291
- Human Gene Mutation Database (Bio-base).
- Lambert S.R., Drack A.V. 1996. Survey of ophthalmology. 40: 427-58. PubMed ID: 8724637
- Lubsen N.H. et al. 1987. Proceedings of the National Academy of Sciences of the United States of America. 84: 489-92. PubMed ID: 3025877
- Santhiya S.T. et al. 2002. Journal of Medical Genetics. 39: 352-8. PubMed ID: 12011157
- Zhang L. et al. 2009. Molecular Vision. 15: 276-82. PubMed ID: 19204787
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.