SoundGeneTM
One of the most common birth defects is hearing loss or deafness, which affects three out of every 1,000 babies born. When a parent learns of his or her child’s diagnosis of hearing loss, a common question is: "Why?"
To help answer this question, Pediatrix Screening has developed SoundGene™, a screening panel that identifies the most common causes of hearing loss. SoundGene is a quick and cost-effective alternative to other sometimes costly and time-consuming methods. Determing the cause of hearing loss may help a healthcare provider better direct the medical managment of the child. Approximately 50 percent of hearing loss cases can be attributed to genetic factors and the remainder to environmental causes.
The SoundGeneTM Screening Panel
Connexin 26(Cx26) GJB2 mutations1:
35delG 167delT
235delC M34T
Connexin 30 (Cx30) GJB6 large deletion
309 kb large deletion
Mitochondrial mutations:
7445A>C (A7445C) 961T>C (T961C)
7445A>G (A7445G) 961T>G (T961G)
7444G>A (G7444A) 961 delT + C(n)ins
Pendred SLC26A4 mutations:
L236P 1001+1G>A
E384G T416P
Cytomegalovirus (CMV) - DNA
Common causes of hearing loss:
- Connexin 26 – Defect in the connexin 26 (Cx26) gene is the most common cause of genetic deafness in the U.S., accounting for more than 50 percent of nonsyndromic (without any other medical problems) and certain syndromic causes of hearing loss. Newborns at risk for hearing loss should have Cx26 testing. Most affected newborns with Cx26 deafness have profound hearing loss at birth, however, some may pass the audiometric hearing screening but develop late onset hearing loss. Most deafness caused by Cx26 responds well to hearing aids and cochlear implants.
- Connexin 30 – The connexin 30 (Cx30) large deletion is most often seen in a person with hearing loss that was found at birth or in early childhood, that is severe or profound, without any other medical problems, and with no identified cause.
- Mitochondrial Conditions – Mitochondria are responsible for producing most of the energy that is needed for the body’s cells to function. A change in mitochondrial genes can shut down some or all the mitochondria, cutting off the essential energy supply, resulting in syndromes involving hearing loss. Nonsyndromic mitochondrial hearing loss is characterized by moderate- to-profound hearing loss, and is transmitted by maternal inheritance.
- Pendred Syndrome – Pendred syndrome is one of the most common types of recessive syndromic hearing loss. Hearing loss is often evident at birth, but in some cases it does not develop until later in infancy or early childhood. Pendred is a result of a defect in the production of the thyroid hormone, an essential hormone for normal body metabolism, which results in improper development of the inner ear. Hearing loss associated with Pendred Syndrome can be severe-to-profound, and tends to be progressive. Approximately one to eight percent of all children with congenital hearing loss have Pendred syndrome.
- Cytomegalovirus (CMV) – Cytomegalovirus, a member of the herpes virus family, is the most common infectious agent present at birth in the United States . Each year, approximately 1 in 150 children are born with congenital CMV infection, which can cause permanent disabilities, including hearing loss. The hearing loss can be unilateral, fluctuating, or progressive in nature, and can be delayed in its onset for months or even years. Congenital CMV infection accounts for approximately 21 to 25 percent of all congenital hearing loss cases.
The entire SoundGene process must be coordinated by you as the ordering healthcare provider. Detailed instructions on how to collect, handle, and submit the blood specimen are included in the SoundGene packet. We recommend that you collect newborn specimen within two weeks after birth, although specimen can be submitted for infants and children of any age. The specimen should be shipped immediately in the prepaid UPS envelope provided.
The results of the screen are reported back to the healthcare provider in an average of 48 hours after the specimen arrives at the laboratory. A genetic counselor with Pediatrix Screening will contact you if abnormal results are detected. Results are mailed to your office and are available by secured Internet access. Our genetic counselors are available to answer any further questions you may have. Please be sure to write your telephone number and mailing address in the spaces designated on the filter paper to ensure timely notification of results.
