Comprehensive Hearing Loss Panel


In general, there is a genetic basis for up to 50% of prelingual hearing loss. Approximately 30% of genetic-related cases are caused by syndromic deafness. Common forms of syndromic hearing loss include Pendred syndrome (enlarged vesitibular aqueduct), Waardenburg syndrome (pigmentary anomalies), and branchio-oto-renal syndrome (brancial-arch and renal anomalies). The remaining 70% of genetic-related deafness is due to non-syndromic, isolated forms of deafness. Non-syndromic hearing loss (NSHL) is a mild-to-profound hearing impairment that occurs in infancy or early childhood, most often prelingually. NSHL may result from genetic or non-genetic causes. While extremely heterogeneous, 70% to 80% of genetic NSHL cases are inherited in an autosomal recessive manner, approximately 20% are inherited in an autosomal dominant manner, and the remainder are due to X-linked and mitochondrial forms of NSHL. Indications for genetic testing for hearing loss may include

  • Clinical status: To clarify the cause of hearing loss, provide information on the likelihood of related health issues, and guide treatment
  • Treatment: To clarify the cause of hearing loss, provide information on the likelihood of related health issues, and guide treatment
  • Family risk: To establish risk to other family members and future generations. Genetic testing can help family members who are susceptible to certain drugs avoid drug-induced hearing loss. For example, aminoglycoside drugs can cause hearing loss in individuals with mutations in the MT-RNR1 gene. Furthermore, testing can confirm syndromic conditions, enabling early detection and surveillance for defects in other organs

The Comprehensive Hearing Loss Panel includes 92 genes that encompass well-established nonsyndromic hearing loss genes, as well as genes associated with syndromic hearing loss that includes Pendred and Waardenburg syndrome. Three additional subpanels for other syndromic forms of hereditary deafness include the Usher Syndrome Subpanel (11 genes), the Branchio-Oto-Renal Syndrome Subpanel (3 genes) and the Zellweger Syndrome Subpanel (9 genes). Targeted familial testing is also available.

Our customizable targeted next-generation sequencing (NGS) panel uses Agilent SureSelect™ target enrichment and Illumina HiSeq sequencing. NGS technology is ideal for diagnostic testing of these disorders due to the extreme locus heterogeneity and phenotype overlap of the genes involved. The sensitivity of this panel is estimated at 99% for single-base substitutions.

If indicated, Sanger sequencing may be performed in both directions using BigDye Terminator chemistry with the ABI 3730 DNA analyzer with target specific amplicons. It may also be used to supplement specific guaranteed target regions that fail NGS sequencing or as a confirmatory method for NGS positive results. NGS technology may not detect all small insertions or deletions. Additionally, it is not diagnostic for large duplications or deletions, repeat expansions, and structural genomic variation. Therefore, multiplex ligation-dependent probe amplification (MLPA) and oligonucleotide array comparative genomic hybridization (aCGH) are available for this test for deletion/duplication analysis. MLPA copy number analysis is available for the DFNB1 (GJB2/GJB6) locus, OTOA, and STRC. This MLPA testing is approximately 99% accurate. The customized oligonucleotide microarray is a highly-targeted, exon-focused array capable of detecting microdeletions and microduplications at a much higher resolution than traditional aCGH methods. The sensitivity of the aCGH assay is estimated to be greater than 99% for medically-relevant microdeletions and microduplications in the exonic regions of 89 genes. Copy number variation of MT-RNR1, P2RX2, and STRC will not be reported using aCGH.


Specimen Requirements

Prenatal

Please provide one of the following specimen types:

  • Two confluent T-25 flasks of cultured cells from amniotic fluid or chorionic villi
  • >4 mg of direct chorionic villi tissue
  • 15 mL of direct amniotic fluid

5-10 mL of blood in an EDTA tube (lavender top) is required from each biological parent. Parental blood samples may be used for maternal cell contamination studies or confirmation studies.

Whole blood

Newborn or child
  • One 2 mL EDTA tube (lavender top) or one 2 mL ACD-A or ACD-B tube (yellow top) from the patient
  • One 5-10 mL EDTA tube (lavender top) or one 5-10 mL ACD-A or ACD-B tube (yellow top) is also recommended from each biological parent

Adult
  • Two 5-10 mL EDTA tubes (lavender top) or two 5-10 mL ACD-A or ACD-B tubes (yellow top) from the patient
  • One 5-10 mL EDTA tube (lavender top) or one 5-10 mL ACD-A or ACD-B tube (yellow top) is also recommended from each biological parent

Extracted DNA

  • A minimum of 10 μL DNA (50-250 ng/μL) is required for testing. 20 μL DNA (50-350 ng/μL) is recommended

Saliva

  • Saliva specimens are accepted upon request. Please contact our laboratory to obtain saliva kits
  • Saliva samples should be collected in Oragene DNA (OG-500) kits by DNA Genotek

Ordering Information

Shipping

  • Tubes of blood, cultured cells, direct chorionic villus sampling, and direct amniotic fluid should be stored and shipped at room temperature or refrigerated
  • Do not freeze specimens
  • Please ship specimens same day or overnight to: 1428 Madison Ave, Atran Bldg, Rm 2-25, New York, NY 10029

Turnaround Time

  • Prenatal: 7-10 business days from receipt of specimen
  • Pediatric or adult: 3-4 weeks from receipt of specimen


Resources

Hearing and Vision Loss Test Requisition
Genetic Testing for Hearing and Vision Loss Brochure