X-linked Juvenile Retinoschisis via the RS1 Gene

Summary and Pricing

Test Method

Sequencing and CNV Detection via NextGen Sequencing using PG-Select Capture Probes
Test Code Test Copy GenesTest CPT Code Gene CPT Codes Copy CPT Codes Base Price
7807 RS1 81479 81479,81479 $640 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
7807RS181479 81479 $640 Order Options and Pricing

Pricing Comments

This test is also offered via our exome backbone with CNV detection (click here). The exome-based test may be higher priced, but permits reflex to the entire exome or to any other set of clinically relevant genes.

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

X-linked Juvenile retinoschisis (XLRS, OMIM 312700) is a relatively common early onset vitreo-retinal degeneration disorder which affects 1 in 5,000-25,000 young males. XLRS is characterized by mild to severe loss in visual acuity, splitting (schisis) of inner retinal layers in the peripheral retina, and a reduction in the b-wave of the electroretinogram (ERG) (George et al. Br J Ophthalmol 79(7):697–702, 1995; Bowles et al. Invest Ophthalmol Vis Sci 52(12):9250-9256, 2011; Sieving et al. GeneReview, 2009). Secondary complications include retinal detachment, vitreous hemorrhage and neovascular glaucoma, which may lead to impaired vision or blindness (George et al., 1995; Li et al. Mol Vis 13:804-812, 2007). The hallmark of XLRS is the occurrence of a “spoke-wheel” pattern in the macula of young patients due to the development of tiny cysts in the retina (Molday et al. Prog Retin Eye Res 31(3):195-212, 2012).

Genetics

RS1 (MIM 300839), which is located on Xp22.1, is the only gene that is mutated in XLRS affected males. RS1 encodes a 224 amino acid (aa) protein called retinoschisin, which is secreted from retinal cells and binds to the surface of photoreceptors and bipolar cells to help maintain the structural and functional integrity of the retina (Molday et al., 2012). XLRS is inherited in an X-linked recessive manner; females are usually asymptomatic and rarely have associated peripheral retinal changes. XLRS is reported to exhibit complete penetrance in males with variable expressivity (Sieving et al., 2009). The RS1 gene comprises six exons, which encode a 23 aa N-terminal leader or signal sequence (exons 1-2), a 39 aa retinoschisin domain (exon 3), a highly conserved 157 aa discoidin domain and a 5 aa C-terminal segment (exons 4–6) (Bowles et al., 2011; Molday et al., 2012). Mutation analysis reveals a high preponderance of causative missense mutations in the discoidin domain, which may affect XLRS1-specific protein-protein interactions and suggest its biological significance. There are over 200 causative mutations in RS1 that have been reported and XLRS seems to be mainly caused by loss-of-function mutations only, rather than an abnormal function from the mutant protein (The Retinoschisis Consortium 1998; The Human Gene Mutation Database).

Clinical Sensitivity - Sequencing with CNV PG-Select

RS1 mutations are identified by sequence analysis in 90–95% of males with a clinical diagnosis of XLRS (Sieving et al. Trans Am Ophthalmol Soc 97:451-464, 1999; Sikkink et al. J Med Genet 44(4):225-232, 2007)

Testing Strategy

This test provides full coverage of all coding exons of the RS1 gene, plus ~10 bases of flanking noncoding DNA. We define full coverage as >20X NGS reads or Sanger sequencing.

Indications for Test

Candidates for this test are patients with symptoms consistent with X-linked Juvenile retinoschisis, family members of patients who have known mutations and carrier testing for at-risk family members.

Gene

Official Gene Symbol OMIM ID
RS1 300839
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Disease

Name Inheritance OMIM ID
Retinoschisis 1, X-Linked, Juvenile XL 312700

Related Test

Name
Flecked Retina Disorder Panel

Citations

  • Bowles, K. et al. (2011). "X-linked retinoschisis: RS1 mutation severity and age affect the ERG phenotype in a cohort of 68 affected male subjects." Invest Ophthalmol Vis Sci  52(12):9250-9256. PubMed ID: 22039241
  • George, N.D. et al. (1995). "X linked retinoschisis." Br J Ophthalmol 79(7):697–702. PubMed ID: 7662639
  • Human Gene Mutation Database (Bio-base).
  • Li, X. et al. (2007). "Clinical features of X linked juvenile retinoschisis in Chinese families associated with novel mutations in the RS1 gene." Mol Vis 13:804-812. PubMed ID: 17615541
  • Molday, R.S. et al. (2012). "X-linked juvenile retinoschisis: clinical diagnosis, genetic analysis, and molecular mechanisms." Prog Retin Eye Res 31(3):195-212. PubMed ID: 22245536
  • Sieving, P.A. et al. (1999). "Juvenile retinoschisis: a model for molecular diagnostic testing of X-linked ophthalmic disease." Trans Am Ophthalmol Soc 97:451-464; discussion 464-9. PubMed ID: 10703138
  • Sieving, P.A. et al. (2009). "X-Linked Juvenile Retinoschisis." GeneReviews. PubMed ID: 20301401
  • Sikkink, S.K. et al. (2007). "X-linked retinoschisis: an update." J Med Genet 44(4):225-232. PubMed ID: 17172462
  • The Retinoschisis Consortium. (1998). "Functional implications of the spectrum of mutations found in 234 cases with X-linked juvenile retinoschisis." Hum Mol Genet 7(7):1185-1192. PubMed ID: 9618178

Ordering/Specimens

Ordering Options

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  • Billing information along with specimen and shipping instructions are within the requisition form.
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Specimen Types

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