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Comprehensive Hearing Loss (NGS Panel and Copy Number Analysis + mtDNA)

CPT: 81460, 81465, 81430, 81431

Genes Assessed


      Specimen Requirements


      Specimen

      Blood | Extracted DNA | Cultured Fibroblasts | Muscle | Buccal Cells


      Volume

      Blood: Draw blood in a lavender top EDTA tube, Sample Stability: 5-7 days, Preferred volume: 4 ml, Minimum volume: 2 ml, DO NOT FREEZE. Extracted DNA: From leukocytes, muscle, or fibroblasts: Preferred quantity: 1 microgram, Minimum quantity: 800 nanograms. Genomic DNA should be eluted in sterile Dnase/Rnase free water or TE. The A260:A280 ratio should be 1.8-2.0. Cultured Fibroblasts: Two T-25 flasks of fibroblasts, preferably ~90% confluent. TAT will be extended by 7-14 days if cells are not confluent upon arrival. Muscle: 50-75 milligrams muscle snap frozen in liquid nitrogen and maintained at -80°Celsius or below. Buccal Cells: One buccal swab should be used for collection. Do not discard solution in collection tube. Follow collection instructions supplied. Stability at ambient temperature is 60 days.


      Container

      Blood: Lavender-Top (EDTA) Tube, Buccal Swab from MNG Kit, Tissue or Extracted DNA: Sterile screw capped vial, Cultured cells: T25 flask


      Collection

      Blood: Specimens should be shipped overnight in a secure container at room temperature. Extracted DNA: Should be shipped overnight at room temperature. If previously frozen, DNA can be shipped in an insulated container with wet or dry ice. Cultured Fibroblasts: T-25 flasks containing fibroblasts should be shipped in an insulated container at room temperature. Flasks should be completely filled with media and cells should be ~90% confluent. Fibroblast samples must be certified free from Mycoplasma. MNG is able to perform this service for a small charge (TC05). For NGS panels, TAT will be extended by 7-14 days if cells are not confluent upon arrival. Muscle: Samples should be shipped frozen in an insulated container with 5-7 lbs. dry ice, overnight. Buccal cells: Should be shipped overnight in a secure container at room temperature.


      Storage Instructions

      Blood - ship ASAP, but stable up to 5 days post-collection at room temperature. DO NOT FREEZE; Swab - 60 day post-collection room temperature stability; DNA - ship at room temperature after extraction; Fibroblasts - ship flask in insulated container at room temp or refigerated; Muscle - ship in insulated container with 5-7 lbs of dry ice


      Stability Requirements

      Room Temperature: Blood - 5 days, Swab - 60 days, DNA - 30 days, Muscle - 0 days, Fibroblasts - 2-3 days; Refrigerated: Blood - 5 days, Swab - 60 days, DNA - 30 days, Muscle - 0 days, Fibroblasts - 2-3 days; Frozen: Blood - DO NOT FREEZE, Swab - 60 days, DNA - Indefinitely, Muscle - Indefinitely, Fibroblasts - Indefinitely; Freeze/Thaw: None


      Causes for Rejection

      Extracted DNA A260:A280 ratio of outside of 1.8-2.0 range; Frozen blood EDTA tube; Thawed and/or fatty muscle sample; Insufficient buccal cell collection


      Test Details


      Use

      Hearing loss is one of the most common neurosensory disorders and can be genetic or acquired. Hearing loss can affect a person either at birth (congenital) or acquired at any stage of life, even if genetic in etiology. (1) Determining the cause or origin of hearing loss in a patient is beneficial as it can enable a personalized approach to their care and treatment options if available.

      Syndromic hearing loss is characterized as hearing loss accompanied with other symptoms and accounts for 30% of all genetic hearing loss caes.1 Common hearing loss syndromes include Usher, which also causes loss of vision, Waardenburg, which is accompanied by changes in coloring and pigmentation of the hair skin and eyes, and Pendred, which causes dysfunction of the kidneys and thyroid. (1,2,3)

      Nonsyndromic hearing loss is a partial or total loss of hearing that is not associated with other signs and symptoms. This type of hearing loss can affect one ear (unilateral) or both ears (bilateral), and can range in severity of loss from mild to profound, often referred to as “deafness”. In addition to autosomal dominant and recessive forms, nonsyndromic hearing loss can also be classified as X-linked or mitochondrial. (4) 

      Related Panels:
      NGS402 Usher Syndrome
      NGS459 Waardenburg Syndrome
      NGS461 Pendred Syndrome
      NGS462 Perrault Syndrome    
      NGS463 Treacher-Collins Syndrome


      Methodology

      Next-Generation Sequencing


      References

      1. Koffler T, Ushakov K, Avraham KB. Genetics of Hearing Loss: Syndromic. Otolaryngol Clin North Am. 2015;48(6):1041‐1061. doi:10.1016/j.otc.2015.07.007
      2. Usher syndrome - Genetics Home Reference - NIH. U.S. National Library of Medicine. https://ghr.nlm.nih.gov/condition/ usher-syndrome. Accessed May 13, 2020.
      3. Waardenburg syndrome - Genetics Home Reference - NIH. U.S. National Library of Medicine. https://ghr.nlm.nih.gov/condition/ waardenburg-syndrome. Accessed May 13, 2020.
      4. Nonsyndromic hearing loss - Genetics Home Reference - NIH. U.S. National Library of Medicine. https://ghr.nlm.nih.gov/condition/nonsyndromic-hearing-loss. Accessed May 13, 2020.


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      SINGLE Blood Genetic Testing, Buccal Swab Genetic Testing