Congenital Hearing Loss Is The Most Common Birth Defect And Hearing Loss Affects Almost All Families
- Universal Newborn Hearing Screening (UNHS) is mandatory in the US and many other countries.
- Worldwide, 1-2 per 1000 babies are born deaf (CDC Data and Statistics). Based on the recent CDC study from 50 states spanning 2015-2017, hearing loss is the most common congenital condition present at birth, more than the most common newborn dry blood spot (DBS) screened conditions (primary Congenital Hypothyroidism, Sickle Cell Disease and Cystic Fibrosis) and critical congenital heart defects (CHD) combined (https://www.cdc.gov/mmwr/volumes/69/wr/mm6936a6.htm?s_cid=mm6936a6_w).
Disorder No. of Cases Reported Hearing Loss 19167 Primary Congenital Hypothyroidism 6629 Sickle Cell Disease (including SS, S b-thalassemia, SC) 5808 Cystic Fibrosis 2145 Critical Congenital Heart Defects 290
- Up to 14.9% of the population between 3-19 years old have some degrees of hearing loss. In the older population, more than 50% of the people are affected.
- Genetic mutations and congenital CMV infection account for 80-90% of all congenital hearing loss cases
Genetic Causes and cCMV Infection Account for ~90% of Congenital Hearing Loss
- 1-2% of infants fail their initial mandatory hearing screen, or a 80-90% of false positive rate.
- Hearing loss is a complex condition associated with a wide array of etiologies. Remarkably, up to 60% of congenital hearing loss and early-onset hearing loss is cuased by genetic factors and about 25-30% are due to congenital CMV (cCMV) infection (PMID: 24651602).
- Mutations in >200 genes can cause hearing loss alone (non-syndromic hearing loss) or in a syndromic form.
- A sensitive test combining deafness gene testing with cCMV detection in newborns who failed universal newborn hearing screening can precisely diagnose the cause for up to 90% of the congenital hearing loss.
- The identification of the genetic cause of hearing loss enables the best intervention and treatment plan.
- cCMV infection is largely asymptomatic at birth (e.g. without purpura/petechiae, jaundice, hepatosplenomegaly, microcephaly, elevated liver enzymes, bilirubinemia, hemolytic anemia or thrombocytopenia). Hearing loss associated with asymptomatic CMV infection often first appears unilaterally and in a milder form that would progress bilaterally and more severely. It is important to screen infants who failed newborn hearing screening (NBHS) to identify hearing loss associated with asymptomatic cCMV, preferably within the first 3 weeks of life.
- American College of Medical Genetics and Genomics (ACMG) established guideline for the clinical evaluation and etiologic diagnosis of hearing loss and practice approach to clinical and diagnostic evaluation for hearing loss, including genetics counseling, differentiation non-syndromic from syndromic hearing loss, and cCMV detection and hearing loss gene testing for non-syndromic hearing loss and syndromic hearing loss gene panel testing for syndromic hearing loss.
GxVISIONTM Congenital Hearing Loss Testing for Molecular Diagnosis of Deafness and Congenital Hearing Loss
Otogenetics offers the most comprehensive deafness gene testing. GxVISIONTM Hearing Loss Test is the only test in the US covering all the deafness genes recommended as must-covered by The American College of Medical Genetics and Genomics (ACMG) and ClinGen Expert Panels (PMID: 30894701). Additionally, GxVISIONTM Congenital Hearing Loss test has the option to detect congenital CMV (cCMV) with the highest sensitivity in the same swab specimen from newborns who failed the Universal Newborn Hearing Screening (UNHS). The Newborn Hearing Screening Working Group of the National Coordinating Center for the Regional Genetics Networks proposed to integrate universal genetic screening and cCMV screening into the current UNHS to improve detection and early intervention of newborns with hearing loss (PMID: 31171844). The GxVISIONTM Congenital Hearing Loss test is the most effective tool to follow up with newborns who have failed the UNHS.
In addition, hearing loss can occur at any age. The deafness gene test can be used to diagnose the genetic cause(s) for hearing loss in patients of any age with a suspected genetic cause.
GxVISIONTM Congenital Hearing Loss testing analyzes a comprehensive panel of deafness genes and detects CMV from the same specimen
245 Hearing Loss Genes Sampled
cCMV Detection at a LOD of 125 copies/ml
Who May Benefit from GxVISIONTM Congenital Hearing Loss Test?
GxVISIONTM Congenital Hearing Loss Test has two options, testing deafness genes only or with CMV detection.
- Newborns who failed the newborn hearing screening is recommended to take the test with the cCMV option as soon as possible. Most genetic hearing loss is inherited in an autosomal recessive pattern and often presents in the absence of a positive family history for hearing loss. 95% of newborns with hearing loss identified by UNHS are born to hearing parents, obscuring the fact that most newborns have a hereditary cause for their hearing loss. The test option with CMV detection is specifically for newborns who failed newborn hearing screening and preferably with specimen collected within the first 3 weeks of life, as detection of CMV in later stages may not represent congenital CMV infection.
- The option of testing deafness genes without cCMV detection is for hearing impaired patients at any age suspected of a genetic cause for hearing loss. Family history and personal medical history, should be submitted.
- Clinical research to investigate deafness gene frequencies in the population of interest, such as a publication investigating Usher (syndromic hearing loss with blindness) gene mutation frequency in certain population.
Option To Test For Novel Deafness Genes
The genetic causes for some Deafness patients remain unknown. Novel genetic causes for deafness may be identified by a more comprehensive genetic test. ACMG guideline recommends exome sequencing for deafness patients who are negative by cCMV and comprehensive deafness gene panel testing.
Here is a publication that applied Otogenetics exome sequencing to determine the genetic causes of hearing loss.