Usher Syndrome Type 1 and Deafness, Autosomal Recessive 23 (DFNB23) via the PCDH15 Gene
Summary and Pricing 
Test Method
Sequencing and CNV Detection via NextGen Sequencing using PG-Select Capture Probes| Test Code | Test Copy Genes | Test CPT Code | Gene CPT Codes Copy CPT Code | Base Price | |
|---|---|---|---|---|---|
| 3225 | PCDH15 | 81407 | 81407,81406 | $990 | Order Options and Pricing |
Pricing Comments
Testing run on PG-select capture probes includes CNV analysis for the gene(s) on the panel but does not permit the optional add on of exome-wide CNV analysis. Any of the NGS platforms allow reflex to other clinically relevant genes, up to whole exome or whole genome sequencing depending upon the base platform selected for the initial test.
An additional 25% charge will be applied to STAT orders. STAT orders are prioritized throughout the testing process.
This test is also offered via a custom panel (click here) on our exome or genome backbone which permits the optional add on of exome-wide CNV or genome-wide SV analysis.
Turnaround Time
3 weeks on average for standard orders or 2 weeks 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.
Clinical Features and Genetics
Clinical Features
Usher syndrome is a clinically heterogeneous disorder characterized by progressive retinitis pigmentosa (RP) and sensorineural hearing impairment with or without vestibular abnormalities. Three types are recognized based on the age of onset, severity of symptoms, and the vestibular involvement. Usher syndrome type 1 is the most common type. It is distinguished by congenital onset of hearing loss, RP in the first decade of life, and abnormal vestibular function (Cohen et al. Int J Audiol 46:82-93, 2007). Features of RP include night blindness progressing to constriction of the peripheral visual field with eventual loss of central vision, an abnormal fundus with bone-spicule deposits and attenuated retinal vessels, and abnormal electroretinographic (ERG) findings (Daiger et al. Arch Ophthalmol 125:151-158, 2007). The vestibular abnormality results in development delay in sitting and walking.
Genetics
Usher syndrome type 1 (USH1) is an autosomal recessive disease that is genetically heterogeneous. Variants in the five genes MYO7A, CDH23, PCDH15, USH1G, and USH1C account for ~75% of cases with detectable variants (Weil et al. Nature 374:60-61, 1995; Bork et al. Am J Hum Genet 68:26-37, 2001; Ahmed et al. Am J Hum Genet 69:25-34, 2001; Bitner-Glindzicz et al. Nat Genet 26:56-60, 2000; Keats and Lentz, GeneReviews, 2010). Variants in the PCDH15 gene account for about 19% of the cases. Over 30 PCDH15 causative variants have been reported. They include nonsense, splicing, small insertions or deletions, and three large deletions. In addition to USH1, PCDH15 variants have been reported in patients with autosomal recessive nonsyndromic hearing loss (DFNB23, OMIM 609533) (Ahmed et al. Hum Mol Genet 12:3215-3223, 2003). The PCDH15 gene encodes protocadherin15, a cell adhesion protein that is important in the development of neurosensory cells in the retina and cochlea.
Clinical Sensitivity - Sequencing with CNV PG-Select
This test allows the detection of variants in ~19% of patients with USH1 (Keats and Lentz, GeneReviews, 2010).
Testing Strategy
This test provides full coverage of all coding exons of the PCDH15 gene, plus ~10 bases of flanking noncoding DNA. We define full coverage as >20X NGS reads or Sanger sequencing.
Indications for Test
All patients with symptoms suggestive of combined neurosensory hearing loss, RP, and vestibular areflexia and no variants in MYO7A or CHD15. The PCDH15 gene is also a candidate for patients presenting with DFNB23. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in PCDH15.
All patients with symptoms suggestive of combined neurosensory hearing loss, RP, and vestibular areflexia and no variants in MYO7A or CHD15. The PCDH15 gene is also a candidate for patients presenting with DFNB23. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in PCDH15.
Gene
| Official Gene Symbol | OMIM ID |
|---|---|
| PCDH15 | 605514 |
| Inheritance | Abbreviation |
|---|---|
| Autosomal Dominant | AD |
| Autosomal Recessive | AR |
| X-Linked | XL |
| Mitochondrial | MT |
Diseases
| Name | Inheritance | OMIM ID |
|---|---|---|
| Usher Syndrome, Type 1D | AR | 601067 |
| Usher Syndrome, Type 1F | AR | 602083 |
Citations
- Ahmed, Z. M., et.al. (2001). "Mutations of the protocadherin gene PCDH15 cause Usher syndrome type 1F." Am J Hum Genet 69(1): 25-34. PubMed ID: 11398101
- Ahmed, Z. M., et.al. (2003). "PCDH15 is expressed in the neurosensory epithelium of the eye and ear and mutant alleles are responsible for both USH1F and DFNB23." Hum Mol Genet 12(24): 3215-23. PubMed ID: 14570705
- Bitner-Glindzicz, M., et.al. (2000). "A recessive contiguous gene deletion causing infantile hyperinsulinism, enteropathy and deafness identifies the Usher type 1C gene." Nat Genet 26(1): 56-60. PubMed ID: 10973248
- Bork, J. M., et.al. (2001). "Usher syndrome 1D and nonsyndromic autosomal recessive deafness DFNB12 are caused by allelic mutations of the novel cadherin-like gene CDH23." Am J Hum Genet 68(1): 26-37. PubMed ID: 11090341
- Cohen M. et al. 2007. International Journal of Audiology. 46: 82-93. PubMed ID: 17365059
- Daiger et al. 2007. PubMed ID: 17296890
- Keats BJ, Lentz J. 2010. Usher Syndrome Type I. In: Pagon RA, Adam MP, Ardinger HH, Wallace SE, Amemiya A, Bean LJ, Bird TD, Dolan CR, Fong C-T, Smith RJ, and Stephens K, editors. GeneReviews(®), Seattle (WA): University of Washington, Seattle. PubMed ID: 20301442
- Weil, D., et.al. (1995). "Defective myosin VIIA gene responsible for Usher syndrome type 1B." Nature 374(6517): 60-1. PubMed ID: 7870171
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
If ordering a Duo or Trio test, the proband and all comparator samples are required to initiate testing. If we do not receive all required samples for the test ordered within 21 days, we will convert the order to the most effective testing strategy with the samples available. Prior authorization and/or billing in place may be impacted by a change in test code.
Specimen Types
Specimen Requirements and Shipping Details
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ORDER OPTIONS
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