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Primary Congenital Glaucoma via the LTBP2 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
11459 LTBP2 81479 81479,81479 $890 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
11459LTBP281479 81479(x2) $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. 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 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

  • Dana Talsness, PhD

Clinical Features and Genetics

Clinical Features

Primary congenital glaucoma (PCG) or Trabeculodysgenesis presents in neonates and during the infantile period, with a varying prevalence rate ranging from 1 in 1,250 to 20,000 among different geographic locations and ethnic groups. The highest prevalence is found in the Gypsy population of Slovakia (1 in 1,250) followed by Saudi Arabians (1:2,500), Southern India (1:3,300), and Western nations (1:5000-22,000) (Gencík et al. 1982; Azmanov et al. 2011; Abu-Amero and Edward 2011). PCG is characterized by elevated intraocular pressure (IOP), increased corneal diameter (megalocornea), enlarged globe (buphthalmos), Haab’s striae (opacification of the cornea with ruptures involving Descemet’s membrane), corneal edema and optic nerve head cupping, thinning of the anterior sclera and atrophy of the iris. Symptoms include photophobia, blepharospasm (abnormal contraction of the eyelid), and hyperlacrimation (excessive tearing). Abnormal development of the anterior segment angle or goniodysgenesis are the hallmarks of congenital glaucoma. It is a chronic disease and a major cause of blindness; earlier detection is needed in order to prevent vision loss (Martin et al. 2000; Abu-Amero and Edward 2011).

Genetics

Currently, mutations in CYP1B1 and LTBP2 have been reported to cause PCG with autosomal recessive inheritance (Abu-Amero et al.2011; Abu-Amero and Edward 2011). LTBP2 is the second gene implicated in PCG after CYP1B1. LTBP2, encoded by LTBP2, is the largest member of the latent transforming growth factor (TGF)-beta binding protein family, that is localized in the anterior segment of the eye at the ciliary body. LTBP2 expression was shown in human eyes, including the trabecular meshwork which is considered to be affected in PCG. LTBP2 was shown to be essential for normal development of the anterior chamber of the eye, where it may have a structural role in maintaining ciliary muscle tone and its surrounding structures (Ali et al. 2009; Narooie-Nejad et al. 2009). So far, about 10 pathogenic variations in LTBP2 have been associated with PCG and the majority of them are null mutations (Human Gene Mutation Database).

Clinical Sensitivity - Sequencing with CNV PGxome

A LTBP2 founder mutation (p.Arg299*), in the Gypsy population, accounts for over 50% of the CYP1B1-negative cases and 40% of overall PCG cases (Ali et al. 2009). In another study, two out of three unrelated CYP1B1-negative PCG affected Iranian families had loss of function mutations in LTBP2, which segregated with the disease and were absent in 400 control individuals (Narooie-Nejad et al. 2009).

Testing Strategy

This test provides full coverage of all coding exons of the LTBP2 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 primary open angle, congenital, juvenile, or adult-onset glaucoma and who have had CYP1B1-negative tests are candidates. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in LTBP2.

Gene

Official Gene Symbol OMIM ID
LTBP2 602091
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Disease

Name Inheritance OMIM ID
Glaucoma 3, Primary Congenital, D 613086

Citations

  • Abu-Amero KK, Edward DP. 2011. Primary Congenital Glaucoma. In: Pagon RA, Adam MP, Bird TD, Dolan CR, Fong C-T, and Stephens K, editors. GeneReviews™, Seattle (WA): University of Washington, Seattle. PubMed ID: 20301314
  • Abu-Amero KK. et al. 2011. Molecular Vision. 17: 2911-9. PubMed ID: 22128238
  • Ali M, McKibbin M, Booth A, Parry DA, Jain P, Riazuddin SA, Hejtmancik JF, Khan SN, Firasat S, Shires M, Gilmour DF, Towns K, et al. 2009. Null Mutations in LTBP2 Cause Primary Congenital Glaucoma. The American Journal of Human Genetics 84: 664–671. PubMed ID: 19361779
  • Azmanov DN. et al. 2011. European Journal of Human Genetics : Ejhg. 19: 326-33. PubMed ID: 21081970
  • Gencík A. et al. 1982. Human Genetics. 61: 193-7. PubMed ID: 7173860
  • Human Gene Mutation Database (Bio-base).
  • Martin SN. et al. 2000. Journal of Medical Genetics. 37: 422-7. PubMed ID: 10851252
  • Narooie-Nejad M, Paylakhi SH, Shojaee S, Fazlali Z, Rezaei Kanavi M, Nilforushan N, Yazdani S, Babrzadeh F, Suri F, Ronaghi M, Elahi E, Paisan-Ruiz C. 2009. Loss of function mutations in the gene encoding latent transforming growth factor beta binding protein 2, LTBP2, cause primary congenital glaucoma. Human Molecular Genetics 18: 3969–3977. PubMed ID: 19656777

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.
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