Pediatric sensorineural hearing loss part 2 07,ringing in ears and pressure in ears,tenis nike kanye west quotes - Step 1

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Exploring the Connexin Connection:Connexin 26 mutations are the most common cause of congenital sensorineural hearing loss, responsible for at least 20 percent of all genetic hearing loss and 10 percent of all childhood hearing loss.
Exploring the Connexin ConnectionConnexin 26 mutations are the most common cause of congenital sensorineural hearing loss, responsible for at least 20 percent of all genetic hearing loss and 10 percent of all childhood hearing loss. Margaret Kenna, MD, MPH, is on the pediatric otolaryngology faculty at Boston Children’s Hospital, where she directed the pediatric cochlear implant program for eight years and has been director of the department’s clinical research since 2003.
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Bridget Gonzalez: I believe that you said in your presentation that Connexin 26 protein is not found in hair cells. Margaret Kenna: It is unclear whether the patients who have Cx26 as the cause of their hearing loss do well because they are generally otherwise healthy and cognitively normal, or whether there is something about the presence in the supporting cells, but not primarily the hair cells, or whether there are other factors. Vaibhavi Dharkar: In your lecture you talked about the Connexin 26 expression in cochlea, liver, bladder and brain. Kenna: In the original Cx26 studies from the late 80s and early 90s, the primary presentations discussed were bilateral severe-to-profound SNHL.
We are doing a study right now trying to begin to get some answers to this question, but I have definitely seen children present with both hearing loss and vestibular dysfunction who have biallelic Cx26 mutations.
Kristen Kowalski: Regarding audiologic phenotype of biallelic mutations … you mention that hearing loss is usually congenital, though normal hearing is detected at birth in 4 to 8 percent—how so?
One of the theories about why [an infant has] normal hearing to start with, then progression, is probably the same as why they progress in general—abnormal protein from the mutations. Sandra Oba: You mentioned there may be a Connexin 26 heterozygous carrier advantage—can you give a bit more information about this? There have also been some reports of a “heterozygous” advantage, postulated because of the relatively high carrier rate of Cx26 mutations in many populations. Donna Ettinger: You state that some GJB2 hearing loss patients have other potential causes of SNHL. For example, a patient with two very clear Cx26 mutations who starts to have night vision issues: The chance they also have Usher Syndrome is low statistically, but I would worry. Terry Sullivan: I work with a woman whose son was born with hearing loss and has what appear to be “cafe au lait” spots and is undergoing genetic testing.
Ellen Mastman: What is the oldest age at which you have noticed hearing loss begin in cases where Cx26 is found?
Kenna: The oldest I have found was about 8 years, and that was a sudden-onset, rapidly progressive SNHL, so a somewhat atypical presentation with somewhat uncommon mutations. Zarin Mehta: I worked with a family that had four children and all but the youngest had bilateral sensorineural hearing loss. Kenna: It certainly sounds recessive, although I guess possibly it could be mitochondrial, especially if the mom had any degree of hearing loss. SIG 6 Perspectives on Hearing and Hearing Disorders: Research and Diagnostics, November 2015, Vol.

Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Pediatric otolaryngologist Margaret Kenna, an expert in congenital and childhood-onset hearing loss, recently led an online chat on Cx26.
Later, I believe you said that people with the Connexin 26 V84L variant did very well with a CI. Can this explain the association of renal disease in association with hearing loss (syndromes like BOR)? What is interesting about many of these genes, such as the EYA1 gene, is that they can obviously affect development as well. From your own research, can you please provide more information about this issue, especially in children? In terms of expression of Cx26, it has mainly been studied in the cochlea; it is now clear that it needs to have much more of an assessment in the vestibular system. Could this be based on how newborn hearing screening is performed—that is, OAE versus ABR etc.—or is that a rate of true normal hearing at birth that turns into a progressive hearing loss over time?
So, either it is truly normal, by ABR or OAE, or the child passes a newborn hearing screen with possible mild hearing loss that becomes more apparent with time. About 40 percent of the Cx26 biallelic patients present with bilateral severe-to-profound SNHL; the others present with measurable hearing, so it is this group of patients who have the possibility of getting worse.
For example, the carriers of single mutations, whose children have biallelic mutations with hearing loss, often have excellent hearing. Several studies have suggested an increased thickness of the epidermis in carriers, potentially making the subjects less susceptible to infection. Does this mean that when the genetic tests show the GJB2 hearing loss, the parents should be advised to keep looking for other causes? In looking at large cohorts of hearing loss patients, things like congenital CMV, Cx26 and EVA are common, and occasionally occur together.
The one thing we do, even if you think there is a clear cause, is test all newborns with hearing loss for CMV, because it is potentially treatable and common. I usually think of neurofibromatosis when I hear of those symptoms, but is there anything else? In theory, NF1 is not supposed to have a higher rate of hearing loss than non-NF1 populations. I think it is certainly possible that much milder phenotypes go unnoticed for long periods of times, so they are not discovered until older ages. The severity of the hearing loss was in the mild-to-moderately severe range and rather similar for all three children. In our patient population, after Cx26 and SLC26A4 (who mainly have EVA), the Usher genes, as a group, are the next most common recessive genes we find. Throughout the webinar I have heard presenters say that people with Connexin 26 losses do well with CIs.

What is quite unclear is why, over time, the hearing may get worse in Cx26-related hearing loss. Vestibular function certainly can be affected; how commonly that happens or whether it gets worse, like the hearing loss can, is less clear. Our patients with Cx26 mutations tend to walk on time, unlike the Usher1 patients, but either present with dizziness or more subtle, but measurable, vestibular dysfunction. With regard to other aspects of the phenotype, we occasionally see patients with mixed hearing losses, and fluctuating losses.
It is also possible that single mutations may be modifiers for other genes or other epigenetic factors, but as I also mentioned, in large groups of patients with SNHL, there seem to be more-than-expected numbers of patients with single Cx26 mutations compared to normal-hearing cohorts. When we see a new patient with hearing loss, I worry about stopping the evaluation without testing for everything, but also know that testing for everything in everyone is usually overkill.
For example, I have several patients with CMV and other things, such as Cx26, CHARGE and EVA. However, we are beginning to notice that many of our NF1 children also have hearing loss, but no evidence of acoustic neuromas, so again, it could be our referral base, or there could be something to it.
No family history of hearing loss except age-related (I worked with the children’s grandfather, too).
So I guess I would be concerned about Usher 2, especially USH2A, the most common Usher 2 gene.
The gene expression is already abnormal to begin with, so either less and less protein is produced, or the work of the supporting cells—where Cx26 is expressed—just goes away over time, affecting the hair cells and ultimately the hearing.
In those patients, I always worry about other additional causes, like CMV or EVA, but we rarely find additional causes of the hearing loss. So, in general, if I find a likely cause that makes sense, and fits the clinical picture, then I will generally not do further testing unless the hearing loss begins to act differently than expected for the current diagnosis. But there are so many other genes, with widely varying frequency depending on the population you are studying.
In the handful of children we follow with NF1 and hearing loss, the hearing loss does not always stay stable, but again it’s not clear why that is. The parents were not interested in further testing, but for such a family, what other mutations might you advise them to look for—especially if the children want to know their risk of passing on the mutation to their offspring? We have recently found children with mutations in otoancorin, and stereocilin, for example, and of course there are many still-undiscovered genes. If you end up getting imaging on these children you must be ready to see and deal with other findings—optic gliomas, etc., which you won’t find in most other children.

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