Congenital Cataracts via the CHMP4B 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
3877 CHMP4B 81479 81479,81479 $890 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
3877CHMP4B81479 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.

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

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 leading cause of reversible blindness in childhood. They account for one-tenth of the cases of childhood blindness (Francis and Moore. 2004. PubMed ID: 14743013). 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. PubMed ID: 8724637).

Genetics

Only 10–25% of congenital cataracts are hereditary. Cataracts are most often inherited as an autosomal dominant trait. CC also exhibit autosomal recessive or X-linked inheritance (Hejtmancik. 2008. PubMed ID: 18035564). X-linked cataract is seen in Nance-Horan syndrome (NHS), which is an especially rare disorder. NHS has cataracts along with prominent dental findings, dysmorphic features, and intellectual disability (Toutain et al. 1997. PubMed ID: 9048931; Stambolian et al. 1990. PubMed ID: 1971992). Currently, isolated or primary cataracts have been mapped to about 39 genetic loci, and over 25 of those are connected to pathogenic variants in specific genes. However, this number is constantly increasing (Hejtmancik. 2008. PubMed ID: 18035564).

Pathogenic variants in CHMP4B are causative for autosomal dominant and recessive congenital cataracts (Yamada et al. 2000. PubMed ID: 10909854; Shiels et al. 2007. PubMed ID: 17701905). To date, two missense variants in this gene have been documented causative (Human Gene Mutation Database). Linkage analysis followed by mutation analysis in a large 6-generation Caucasian family with autosomal dominant “progressive childhood posterior subcapsular” cataracts identified a heterozygous missense variant (c.386A>T) that segregated with the disease in this large pedigree (Shiels et al. 2007. PubMed ID: 17701905). CHMP4B encoded charged multivesicular body protein is major binding partner of the ALG-2-interacting protein Alix and is involved in multivesicular body sorting (Katoh et al. 2003. PubMed ID: 12860994).

Clinical Sensitivity - Sequencing with CNV PGxome

Predicting clinical sensitivity for the CHMP4B gene is challenging due to genetic heterogeneity of cataracts and also due to the limited number of CHMP4B-associated cataract cases.

Testing Strategy

This test provides full coverage of all coding exons of the CHMP4B 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 congenital progressive childhood posterior subcapsular cataracts are candidates.

Gene

Official Gene Symbol OMIM ID
CHMP4B 610897
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Disease

Name Inheritance OMIM ID
Cataract 31 AD 605387

Related Test

Name
Congenital Cataracts Panel

Citations

  • Francis and Moore. 2004. PubMed ID: 14743013
  • Hejtmancik. 2008. PubMed ID: 18035564
  • Human Gene Mutation Database (Bio-base).
  • Katoh et al. 2003. PubMed ID: 12860994
  • Lambert and Drack. 1996. PubMed ID: 8724637
  • Shiels et al. 2007. PubMed ID: 17701905
  • Stambolian et al. 1990. PubMed ID: 1971992
  • Toutain et al. 1997. PubMed ID: 9048931
  • Yamada et al. 2000. PubMed ID: 10909854

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

loading Loading... ×

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: $
×
Copy Text to Clipboard
×