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Deafness, Autosomal Recessive 42 (DFNB42) via the ILDR1 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
ILDR1 81479 81479,81479 $990
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
11395ILDR181479 81479,81479 $990 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 platform).

Click here for costs to reflex to whole PGnome (if original test is on PGnome Sequencing platform).

The Sanger Sequencing method for this test is NY State approved.

For Sanger Sequencing click here.

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.


Genetic Counselors


  • Ben Dorshorst, PhD

Clinical Features and Genetics

Clinical Features

Autosomal recessive deafness 42 (DFNB42) is characterized by prelingual, stable or non-progressive, bilateral, moderate to profound, sensorineural hearing impairment. Most individuals diagnosed with DFNB42 have more pronounced hearing loss for higher frequencies, as indicated by a downsloping audiogram (Kim et al. 2015). A small percentage of DFNB42 patients present a flat audiogram, which indicates hearing impairment for all frequencies (Borck et al. 2011). The audioprofile of most nonsyndromic hearing loss cases can be distinct, thus assisting in the development of an evaluation strategy for molecular genetic testing and in generating a prognosis on the rate of hearing loss per year (Hildebrand et al. 2008). Patients diagnosed with DFNB42 generally do not elicit otoacoustic emissions, thus indicating that this disorder is caused by cochlear dysfunction and is not a form of auditory neuropathy (Borck et al. 2011). DFNB42 is not associated with facial dysmorphisms, intellectual disabilities, eye abnormalities, or anomalies in blood chemistry, thyroid function tests, and urinalysis.


DFNB42 is an autosomal recessive hearing disorder that is caused by pathogenic sequence variants in the immunoglobulin-like domain-containing receptor 1 (ILDR1) gene, which is located in chromosome 3q13.3 (Borck et al. 2011). The ILDR1 gene consists of 8 coding exons that encode a 546-amino acid protein that is expressed during inner ear development, particularly in the cochlea, which includes the organ of Corti, stria vascularis, utricle, and saccule (Sang et al. 2014; Higashi et al. 2013). Although the exact function of the ILDR1 protein remains elusive, studies have suggested that it influences the epithelial barrier function of supporting cells of the cochlea. The ILDR1 protein is considered a member of the angulin protein family, which comprises three epithelial cell corner proteins that generate a tricellular tight junction (Higashi et al. 2013). Cellular studies using mouse models have indicated that pathogenic variants in the ILDR1 gene result in postnatal cochlear hair cell degeneration (Morozko et al. 2014; Higashi et al. 2015; Sang et al. 2015). To date, a total of about 16 pathogenic ILDR1 sequence variants have been reported to cause hearing loss, which include 9 missense/nonsense, 2 splicing, 4 small deletions, and 1 small insertion (Human Gene Mutation Database).

Clinical Sensitivity - Sequencing with CNV PGxome

The clinical sensitivity of this test has been reported to range from 3% to 5%. In two independent research studies, pathogenic ILDR1 sequence variants were detected in 3.5% (5/144) and 5% (1/20) of Iranian families with autosomal recessive nonsyndromic hearing loss (Babanejad et al. 2012; Diaz-Horta et al. 2012). In a multiethnic cohort consisting of 160 families with autosomal recessive nonsyndromic deafness, 5 families (3.1%) showed disease-causing sequence variants in the ILDR1 gene (Bademci et al. 2015).

Testing Strategy

This test provides full coverage of all coding exons of the ILDR1 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

The ideal ILDR1 test candidates are individuals who present with prelingual, non-progressive, bilateral, moderate to profound, autosomal recessive nonsyndromic hearing loss. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in ILDR1.


Official Gene Symbol OMIM ID
ILDR1 609739
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


Name Inheritance OMIM ID
Deafness, Autosomal Recessive 42 AR 609646


  • Babanejad M. et al. 2012. American Journal of Medical Genetics. Part A. 158A: 2485-92. PubMed ID: 22903915
  • Bademci G. et al. 2015. Genetics in Medicine : Official Journal of the American College of Medical Genetics. 0: N/A. PubMed ID: 26226137
  • Borck G. et al. 2011. American Journal of Human Genetics. 88: 127-37. PubMed ID: 21255762
  • Diaz-Horta O. et al. 2012. Plos One. 7: e50628. PubMed ID: 23226338
  • Higashi T. et al. 2013. Journal of Cell Science. 126: 966-77. PubMed ID: 23239027
  • Higashi T. et al. 2015. Plos One. 10: e0120674. PubMed ID: 25822906
  • Hildebrand MS. et al. 2008. Genetics in Medicine : Official Journal of the American College of Medical Genetics. 10: 797-804. PubMed ID: 18941426
  • Human Gene Mutation Database (Bio-base).
  • Kim N.K. et al. 2015. Plos One. 10: e0116931. PubMed ID: 25668204
  • Morozko E.L. et al. 2015. Human Molecular Genetics. 24: 609-24. PubMed ID: 25217574
  • Sang Q. et al. 2014. Human Molecular Genetics. 23: 6201-11. PubMed ID: 24990150
  • Sang Q. et al. 2015. Biology Open. 4: 411-8. PubMed ID: 25819842


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

PGxome (Exome) Sequencing Panel

PGnome (Genome) Sequencing Panel

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Note: acceptable specimen types are whole blood and DNA from whole blood only.
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