Bradyopsia (Retinal Dysfunction) via the RGS9 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
13029 RGS9 81479 81479,81479 $890 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
13029RGS981479 81479 $890 Order Options and Pricing

A 25% additional charge will be applied to STAT orders. View STAT turnaround times here.

For Reflex to PGxome pricing click here.

Targeted Testing

For ordering sequencing of targeted known variants, go to our Targeted Variants page.

Turnaround Time

18 days on average

EMAIL CONTACTS

Genetic Counselors

Geneticist

Clinical Features and Genetics

Clinical Features

Bradyopsia or RGS9/RGS9BP-associated retinopathy is a rare retinal dysfunction that is inherited in an autosomal recessive manner. It is clinically characterized by reduced central vision from childhood due to cone dysfunction, mild photophobia, normal color vision, lack of nystagmus, normal fundi and distinctive electrophysiologic features (Michaelides et al. 2010. PubMed ID: 19818506). The chief complaint of all patients was difficulty tracking moving objects and adapting to sudden changes in luminance levels. Walking out of a house into the sunlight for example causes temporary severe blindness (Kooijman et al. 1991. PubMed ID: 1790747).

With the advent of gene therapy and other types of treatments, the identification of causative genes and variants is becoming increasingly important.

Genetics

Pathogenic variants in either RGS9 (encoding a GTPase-activating protein) or RGS9BP (encoding its membrane anchor protein) have been identified in patients with autosomal recessive bradyopsia or RGS9/RGS9BP-associated retinopathy (Strauss et al. 2015. PubMed ID: 26343007). Both genes play a critical role in the recovery phase of visual transduction (Strauss et al. 2015. PubMed ID: 26343007; Nishiguchi et al. 2004. PubMed ID: 14702087). To date, less than 5 pathogenic variants (missense and nonsense) in RGS9 have been reported to cause bradyopsia (Michaelides et al. 2010. PubMed ID: 19818506; Nishiguchi et al. 2004. PubMed ID: 14702087; Human Gene Mutation Database). De novo variants have not been reported in either RGS9 or RGS9BP.

Mouse model studies suggested that RGS9 is required for normal inactivation of the cone phototransduction cascades (Lyubarsky et al. 2001. PubMed ID: 11262419). In both RGS9 and R9AP knockout mice, a small delay was observed in ON-bipolar cell light responses manifested as delayed onset of electroretinography b-waves. This is consistent with the prolonged electroretinal response suppression (PERRS) in the Bradyopsia patients (Herrmann et al. 2011. PubMed ID: 22096596; Kooijman et al. 1991. PubMed ID: 1790747).

Testing Strategy

This test is performed using Next-Gen sequencing with additional Sanger sequencing as necessary.

This test provides full coverage of all coding exons of the RGS9 gene plus 10 bases flanking noncoding DNA in all available transcripts in addition to 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.

Since this test is performed using exome capture probes, a reflex to any of our exome based tests is available (PGxome, PGxome Custom Panels).

Clinical Sensitivity - Sequencing with CNV PGxome

Predicting clinical sensitivity for the RGS9 gene is challenging due to genetic heterogeneity and the limited number of cases. All the documented causative variants are detectable by this NGS technology.

Indications for Test

All patients with symptoms suggestive of bradyopsia are candidates. The term was proposed due to the the patients’ difficulty in adapting to changes in luminance. Targeted testing is indicated for family members of patients who have known pathogenic variants in RGS9. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in RGS9.

Gene

Official Gene Symbol OMIM ID
RGS9 604067
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Disease

Name Inheritance OMIM ID
Prolonged Electroretinal Response Suppression AR 608415

Citations

  • Herrmann et al. 2011. PubMed ID: 22096596
  • Human Gene Mutation Database (Bio-base).
  • Kooijman et al. 1991. PubMed ID: 1790747
  • Lyubarsky et al. 2001. PubMed ID: 11262419
  • Michaelides et al. 2010. PubMed ID: 19818506
  • Nishiguchi et al. 2004. PubMed ID: 14702087
  • Strauss et al. 2015. PubMed ID: 26343007

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.

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

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ORDER OPTIONS

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