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Cataract 17, Multiple Types (CTRCT17) via the CRYBB1 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
3885 CRYBB1 81479 81479,81479 $890 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
3885CRYBB181479 81479,81479 $890 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 backbone).

Click here for costs to reflex to whole PGnome (if original test is on PGnome Sequencing backbone).

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

For Sanger Sequencing click here.

Turnaround Time

18 days on average for standard orders or 13 days 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.

EMAIL CONTACTS

Genetic Counselors

Geneticist

  • Jamie Fox, PhD

Clinical Features and Genetics

Clinical Features

Cataract 17 (CTRCT17) is a common congenital, bilateral, progressive, nuclear, pulverulent, sutural vision disorder that causes blindness in children (Mackay et al. 2002). It is characterized by the development of blurred and dimmed vision resulting from clouding of the lens (opacification) due to changes in its microarchitecture (Kumar et al. 2013). This particular damage to the lens induces light to scatter as well as proteins to aggregate, thereby resulting in loss of transparency (Hejtmancik 2008). Intrafamilial variability in the morphology and location within the lens commonly occurs in CTRCT17 (Yang et al. 2008). The incidence of congenital cataract has been estimated to be roughly 2 per 10,000 live births (Wirth et al. 2002; Yi et al. 2011). Perinatal ocular examination in newborns via red reflex examination is generally conducted using an ophthalmoscope (American Academy of Pediatrics 2002), whereas young children are assessed by slit-lamp microscopy (Li et al. 2013). Congenital cataract is usually treated by surgery and early primary intraocular lens implantation during the first year of life (Ventura et al. 2013). CTRCT17 has been strongly associated with microcornea (Willoughby et al. 2005).

Genetics

CTRCT17 is an autosomal dominant vision disorder that is caused by pathogenic sequence variants in the crystallin, beta-B1 (CRYBB1) gene, which is located on chromosome 22q12.1 (Mackay et al. 2002). The CRYBB1 gene consists of five coding exons that encode a 252-amino acid structural protein called beta-crystallin B1, which is expressed in the lens tissue and plays an important structural role in the maintenance of lens transparency and refractive index (David et al. 1996). The CRYBB1 protein has a significantly longer N-terminal extension compared to the other two beta-crystallins, namely CRYBB2 and CRYBB3, thereby allowing the formation of higher molecular weight protein aggregates (Den Dunnen et al. 1986; Ajaz et al. 1997). Pathogenic sequence variants in the CRYBB1 gene significantly reduce the stability of the beta-crystallin B1 monomer via deamidation, thus disrupting the formation of hetero-oligomers and protein folding, which are critical for lens transparency (Harms et al. 2004; Wang et al. 2010; Wang et al. 2013). To date, a total of over 10 pathogenic CRYBB1 sequence variants have been reported, which are mostly missense and a few chain terminations (nonsense and frame shift) (Human Gene Mutation Database). The autosomal recessive form of CTRCT17 less frequency occurs and involves the abrogation of the N terminal region, thus leading to nonsense-mediated decay and ultimately no protein product (Cohen et al. 2007; Meyer et al. 2009).

Clinical Sensitivity - Sequencing with CNV PGxome

The clinical sensitivity of this test may range up to 18%. In China, none of the 25 families with congenital cataracts showed pathogenic sequence variants in the CRYBB1 gene (Sun et al. 2011). In two independent studies in India, none of the 60 south Indian families with inherited pediatric cataract (Devi et al. 2008) and 8% (8/100) of congenital cataract cases (Kumar et al. 2013) showed disease-causing CRYBB1 sequence variants. In the United States, 4.3% (1/23) of families with autosomal dominant cataract tested positive for causative CRYBB1 sequence variants (Reis et al. 2013). In Saudi Arabia, 18% (7/38) of pediatric cataract patients harbored pathogenic sequence variants in the CRYBB1 gene (Aldahmesh et al. 2012).

Testing Strategy

This test provides full coverage of all coding exons of the CRYBB1 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 CRYBB1 test candidates are individuals who present with congenital, bilateral, progressive, nuclear, pulverulent, sutural autosomal dominant cataract.

Gene

Official Gene Symbol OMIM ID
CRYBB1 600929
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Disease

Name Inheritance OMIM ID
Cataract 17 AD,AR 611544

Citations

  • Ajaz M.S. et al. 1997. The Journal of Biological Chemistry. 272: 11250-5. PubMed ID: 9111027
  • Aldahmesh M.A. et al. 2012. Genetics in Medicine. 14: 955-62. PubMed ID: 22935719
  • American Academy of Pediatrics. 2002. Pediatrics. 109: 980-1. PubMed ID: 11986467
  • Cohen D. et al. 2007. Investigative Ophthalmology & Visual Science. 48: 2208-2213. PubMed ID: 17460281
  • David L.L. et al. 1996. The Journal of Biological Chemistry. 271: 4273-9. PubMed ID: 8626774
  • den Dunnen J.T. et al. 1986. Proceedings of the National Academy of Sciences of the United States of America. 83: 2855-9. PubMed ID: 3458246
  • Devi R.R. et al. 2008. Molecular Vision. 14: 1157-70. PubMed ID: 18587492
  • Harms MJ. et al. 2004. Protein Science : a Publication of the Protein Society. 13: 678-86. PubMed ID: 14978307
  • Hejtmancik J.F. 2008. Seminars in cell & developmental biology. 19: 134-49. PubMed ID: 18035564
  • Human Gene Mutation Database (Bio-base).
  • Kumar M. et al. 2013. Molecular Vision. 19: 2436-50. PubMed ID: 24319337
  • Li L.H. et al. 2013. The British Journal of Ophthalmology. 97: 588-91. PubMed ID: 23426739
  • Mackay D.S. et al. 2002. American Journal of Human Genetics. 71: 1216-21. PubMed ID: 12360425
  • Meyer E. et al. 2009. Molecular Vision. 15: 1014-9. PubMed ID: 19461930
  • Reis L.M. et al. 2013. Human genetics. 132: 761-70. PubMed ID: 23508780
  • Sun W. et al. 2011. Molecular vision. 17: 2197-206. PubMed ID: 21866213
  • Ventura M.C. et al. 2013. Arquivos Brasileiros De Oftalmologia. 76: 240-3. PubMed ID: 24061837
  • Wang K.J. et al. 2011. Human Mutation. 32: E2050-60. PubMed ID: 21972112
  • Wang S. et al. 2013. Biochimica Et Biophysica Acta. 1832: 302-11. PubMed ID: 23159606
  • Willoughby C.E. et al. 2005. Molecular Vision. 11: 587-93. PubMed ID: 16110300
  • Wirth M.G. et al. 2002. The British Journal of Ophthalmology. 86: 782-6. PubMed ID: 12084750
  • Yang J. et al. 2008. Molecular Vision. 14: N/A. PubMed ID: 18432316
  • Yi J. et al. 2011. International Journal of Ophthalmology. 4: 422-32. PubMed ID: 22553694

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


Specimen Types

Specimen Requirements and Shipping Details

PGxome (Exome) Sequencing Panel

PGnome (Genome) Sequencing Panel

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ORDER OPTIONS

View Ordering Instructions

1) Select Test Method (Backbone)


1) Select Test Type


2) Select Additional Test Options

STAT and Prenatal Test Options are not available with Patient Plus.

No Additional Test Options are available for this test.

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