{"id":2281,"date":"2013-05-14T18:27:59","date_gmt":"2013-05-14T15:27:59","guid":{"rendered":"https:\/\/earbook.online\/pora\/?p=2281"},"modified":"2014-08-28T13:40:05","modified_gmt":"2014-08-28T10:40:05","slug":"tatyana-markova-answers-genetics-hearing-loss","status":"publish","type":"post","link":"https:\/\/earbook.online\/pora\/blog\/2013\/05\/tatyana-markova-answers-genetics-hearing-loss\/","title":{"rendered":"Tatyana Markova answers the questions of experts and parents in the webinar on Genetics, 31.03.2013"},"content":{"rendered":"

[Elena Zueva] If parents are carriers of mutations in different genes, will a child who has a genotype with two faulty genes (for example, connexin and another) be hearing-impaired?
\n<\/strong> <\/em>We must be aware that every gene has a duplicate – one variant from the mother, and one from the father. So if we talk about the connexin 26 gene – indeed, if both variants of it have mutations, this will lead to hearing loss. In other cases, when we have flaws in different genes – for example, one of the parents may have flaws in both variants of the connexin 26 gene, and the other could be hearing-impaired because of problems in another gene (but the connexin gene is wholesome). This couple will produce normally hearing children, because different genes are accountable for different proteins.<\/p>\n

[\u0415\u043a\u0430\u0442\u0435\u0440\u0438\u043d\u0430] A child was diagnosed with bilateral chronic profound sensorineural hearing loss, prelingual, sporadic, genetic (autosome recessive OMIM 220290). Molecular screening revealed the proband as heterozygote carrier of the mutation 35delG in the connexin 26 gene (GJB2).
\nWe would like to ask for advice.
\nWhat is the maximum we can do to now have a healthy child?
\nMaybe a certain hiatus is needed between pregnancies, or the children should be of different gender? Slide 26 of your presentation made me think of this.<\/strong>
\n<\/em>Carriership of a mutation means the presence of one recessive mutation, which does not lead to hearing loss. HL is the result of a combination of two recessive mutations. Therefore, if search of only one mutation was conducted, the analysis is incomplete. The whole gene must be screened and the second mutation located.
\nThe connexin 26 gene is located on a regular chromosome and is not linked with gender (the sexual X and Y chromosomes). Therefore, boys and girls, second and firstborn children are equally susceptible. Both older and younger children can be healthy, in the current marriage or in another. For two carriers of the mutation, the risk for every pregnancy is 25%. The sperm and egg cells contain only one variant of the gene, and so we cannot predict which of them will combine. There is a 50% likelihood of a carrier passing on his modified gene to a healthy child.<\/p>\n

[\u0420\u043e\u043c\u0430\u043d \u0433.\u0412\u043b\u0430\u0434\u0438\u043a\u0430\u0432\u043a\u0430\u0437]<\/strong><\/em> Is there a point in having a genetic analysis at the maternity ward if we have audiological screening anyway? Is this really necessary? <\/em><\/strong>
\nExperience indicates it would be of some benefit if a genetic analysis could be used to support audiological screening. Around 10-12% of children with a modified connexin 26 gene pass the OAE test, so we miss these 10-12%. If we had access to a report on a pathological genotype, the child would be given complete audiological assessment immediately, instead of repeat OAE registrations, which is what we do now.
\n<\/p>\n

[Monika Lehnhardt] What do parents do if they know early on of the risk of deafness for the child? What is the goal of prenatal diagnostics?<\/strong><\/em>
\nThere is a possibility to investigate the foetus’s genotype at the 10-12th weeks of pregnancy. The purpose of the diagnostics is to inform the parents of the child’s genotype. The family should be ready for such a test, that is, they should have the results for their older child or for themselves; they must be aware of where it is done and how. The results are discussed case by case. There must be no external influences and no premeditated opinions on behalf of the professional. As people are different, they will act differently, too. As far a s we know, those who want the children, will have them, and those who are afraid, unfortunately, will not. The frequency of requests for prenatal diagnostics of the connexin 26 gene-related deafness is currently low. One of the possible reasons is that cochlear implantation provides quite a successful treatment for these cases.<\/p>\n

[Monika Lehnhardt] Am I right i understanding that there is no in-utero treatment available yet? <\/strong><\/em>
\nYes, this is the prospect, but as of now no such thing exists.<\/p>\n

[Ibragimova Elena-Petropavlovsk] What is the procedure for submitting genetic material? How flaw-proof is the analysis? <\/strong><\/em>
\nMaterial from parents won’t be required for the primary submission. The hearing-impaired child provides the samples – usually the blood, sometimes it could be epithelium from inside the cheek. The sample can be sent to the lab of the Moscow Center for Molecular Diagnostics as a sterile tissue with a blood stain.
\nAs for error rates, they are extremely low if the sample is taken and the test carried out with due diligence. Then, this also depends on the method – e.g. the lab might look just for frequent mutations. In any case, nothing stops you from having a repeat check.<\/p>\n

[Olga Peskova-Dallas] What is the percentile precision of the genetic testing? Where is it carried out? Can patients be referred, and how? Is this part of neonatal screening? Do parents pay? What is the most typical of the analyses? What do you recommend to parents? How long does it all take? <\/strong><\/em>
\nThe precision is at 100% (though we leave a margin of 1-2% to unknown variables). The method we use in the Moscow Center for Molecular Diagnostics involves analysis of the whole gene, so it is precise. Thus, if mutations in the set of genes are located, they are 100% there. If they are not found, it is possible that there are other changes in the gene. In case changes in the connexin 26 gene are found, this can be verified by analysing samples of the parents.
\nIn Moscow the cost is 2500 RUR, in the USA I know it to be on average 200 USD. The test takes 2-3 weeks. In Italy all children diagnosed with hearing impairment undergo genetic screening for free. We don’t have that yet.
\nWe have just audiological newborn screening, and the genetic test is not part of that (for now newborns are tested for other hereditary illnesses).
\nBefore conception, parents can have themselves tested for the four most prevalent hereditary diseases (phenylketonuria, mucoviscedosis, hypothyroidism, hearing loss), and the connexin 26 analysis is included.
\nParents must be informed on why the genetic test is necessary: to know the true reason, to forecast the progress, to be informed so that their children and themselves have adequate expectations regarding their progeny.<\/p>\n

[Anastasia Slukhai-Kiev] This is a question burning in the mind of all parents with hearing-impaired children. What is the chance of having further deaf offspring if parents and closest relatives (brothers, sisters, grandparents, aunts, uncles etc.) are hearing? <\/strong><\/em>
\nIn case flaws of the gene (mutations) are discovered in the child, parents can have themselves checked for mutations of this gene. The laws of genetics have it that the gene was passed on by the parents. If mutations in the connexin 26 gene are found, they must be present with the parents as well (one for each). In case one parent carrying the recessive mutation (healthy in body) meets another carrier like himself, the law is that the risk is 25% to have a deaf child, 50% a healthy carrier, and 25% fully healthy. In my practice I’ve dealt with a family who had 3 healthy children, and the fourth one received both the faulty gene copies, which made him hearing-impaired.<\/p>\n

[Anna Makukhina-Sankt-Petersburg] If otoacounstic emissions are not registered, does this mean a high chance of a genetic impairment (such as connexin)? Should I refer parents to our molecular genetics center in St. Petersburg? <\/strong><\/em>
\nAbsence of registered OAE is a reason to take the newborn to a surdologist, but genetic losses should not be inferred immediately. In case the OAE is not registered in a maternity ward screening (no risk factors, no other severe disorders), and then a full audiological testing is conducted and congenital hearing loss is confirmed, in 70% of cases this implies a genetic foundation of the hearing loss. 10-12% of children pass the OAE test after birth, but then parents notice lack of response to sounds. Then it is discovered, late rather than early, that the child is hearing-imapired. Families often come to see an ENT doctor then, and it is important that they are referred to a surdologist. As for genetic screening for hearing defects, in St. Petersburg it is not set up in full, and only frequent mutations are diagnosed.
\n<\/p>\n

[\u0415\u043a\u0430\u0442\u0435\u0440\u0438\u043d\u0430-\u0427\u0435\u043b\u044f\u0431\u0438\u043d\u0441\u043a] If we know we carry the GJB gene, can we plan for the birth of a hearing child? IVF? <\/strong><\/em>
\nIVF does not allow choosing an embryo with the right genotype – the failure rate with analysing just the one available cell is way too high. With IVF, at 10-12 weeks of pregnancy, you can undergo genetic diagnostics. If the genotype of the foetus has two mutations, the hearing impairment will be in place, but we cannot forecast the severity. You are the ones making the decision as you take your family’s situation into account. The parents’ decision must not be influenced by anyone.<\/p>\n

[Lilit – Yerevan] L. Balabekyan is asking whether the deafness of the child’s great-grandmother means that the child is deaf for reasons of genetics? Can removal of two teeth during pregnancy cause deafness in a child? <\/strong><\/em>
\nSamples should be submitted and tested, the impairment may as well be genetic. The teeth are likely not at fault.<\/p>\n

[\u0420\u043e\u043c\u0430\u043d \u0433.\u0412\u043b\u0430\u0434\u0438\u043a\u0430\u0432\u043a\u0430\u0437] Can a birthing trauma cause damage to the gene?<\/strong><\/em>
\nWhen we speak of tooth removal or of birth circumstances, we must realize neither of them entail changes in the genes. However, they may combine with the genetic factors. It is proven that the age of the common 35delG mutation in the connexin 26 gene is more than 10,000 years old. We suggest ruling out the coincidence of acquired and hereditary risk factors, through a genetic analysis.<\/p>\n

[Oleg Zyabrikov-Moscow] Does a mutation of the GJB2 gene affect only the auditory nerve, or the cilia as well? We are planning to have our child implanted, so it matters that the nerve is be functional. <\/strong><\/em>
\nA mutation in the GJB2 gene does not cause damage to the nerve itself. The stereocilia are also morphologically intact, but without the connexin canals they can’t function properly. Normally they should convert the sound wave into an electric signal, which is then passed on to the nerve fibers of the hearing nerve. In case of a pathology of connexin channels, sound perception is compromised, and information does not reach the auditory nerve.<\/p>\n

[Monika Lehnhardt] What is the percentage of newborns undergoing audiological screening in Russia?<\/strong><\/em>
\nUniversal audiological screening is conducted nationwide. The data differs across regions – there are those where the coverage is 95%, 80% or lower. The total rate for 2012 is 70%.
\nIn certain maternity hospitals the screening is absent. Even in Moscow there are clinics where OAE are not measured. In this case the parents must find a polyclinic where they can have the tests at 1 month of the baby’s age.<\/p>\n

[Vera Lyubomudrova – Moscow] Does this mutation affect any other organs? Are there other conditions characteristic of persons with the mutation?<\/strong><\/em>
\nIn most cases there are no other pathologies involved in addition to the hearing loss. An accompanying pathology is possible, just like for any other child. We often find hemangiomas in persons with a flawed connexin 26 gene. But this needs in-depth investigation, I cannot provide any data now.
\nA completely different subject are dominant mutations in the connexin 26 gene, which manifest themselves in hearing loss and skin conditions, but on the whole this is very rare.<\/p>\n

[\u0415\u043a\u0430\u0442\u0435\u0440\u0438\u043d\u0430-\u0427\u0435\u043b\u044f\u0431\u0438\u043d\u0441\u043a] Does a CI affect the heart, or sight? A friend’s family noticed that four years after implantation, the child started losing sight and started experiencing heart murmur.<\/strong><\/em>
\nI would recommend a genetician’s consultation. First, a syndrome must be eliminated. Every situation should be treated individually; however, this is unlikely to be connected with the implant.<\/p>\n","protected":false},"excerpt":{"rendered":"

[Elena Zueva] If parents are carriers of mutations in different genes, will a child who has a genotype with two faulty genes (for example, connexin and another) be hearing-impaired? We must be aware that every gene has a duplicate – one variant from the mother, and one from the father. So if we talk about … <\/p>\n

Read more<\/a><\/p>\n","protected":false},"author":506,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_bbp_topic_count":0,"_bbp_reply_count":0,"_bbp_total_topic_count":0,"_bbp_total_reply_count":0,"_bbp_voice_count":0,"_bbp_anonymous_reply_count":0,"_bbp_topic_count_hidden":0,"_bbp_reply_count_hidden":0,"_bbp_forum_subforum_count":0,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[33],"tags":[39,107,74],"class_list":["post-2281","post","type-post","status-publish","format-standard","hentry","category-questions-and-answers","tag-genetics","tag-hearing-loss","tag-syndromes"],"jetpack_featured_media_url":"","jetpack-related-posts":[{"id":9151,"url":"https:\/\/earbook.online\/pora\/blog\/2023\/12\/profile-monika-lehnhardt-goriany\/","url_meta":{"origin":2281,"position":0},"title":"Profile: Monika Lehnhardt-Goriany","author":"Michael Goriany","date":"December 11, 2023","format":false,"excerpt":"Monika Lehnhardt-Goriany was born in Vienna and graduated from the University Alma Mater Rudolfina. She obtained her PhD in philology, psychology and philosophy. During her professional career she has held various positions in German, American and Swedish companies. 1987 she established Cochlear Europe in Basel, Switzerland. She gained broad experience\u2026","rel":"","context":"In "export_posts"","block_context":{"text":"export_posts","link":"https:\/\/earbook.online\/pora\/blog\/category\/export_posts\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/earbook.online\/pora\/wp-content\/uploads\/2023\/12\/Monika-Lehnhardt-e1323278099229-211x300.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":3612,"url":"https:\/\/earbook.online\/pora\/blog\/2018\/10\/forum-discussion-the-muenster-support-program-for-parents-of-children-with-hearing-loss-k-reichmuth-october-14th-2018\/","url_meta":{"origin":2281,"position":1},"title":"Forum discussion: The Muenster Support Program for Parents of Children with Hearing Loss \u2013 K. Reichmuth, October 14th 2018","author":"","date":"October 9, 2018","format":false,"excerpt":"","rel":"","context":"In "Next Forum Discussions for Experts"","block_context":{"text":"Next Forum Discussions for Experts","link":"https:\/\/earbook.online\/pora\/blog\/category\/pora-therapists-other-experts\/next-forum-discussions-experts\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/earbook.online\/pora\/wp-content\/uploads\/2018\/10\/PORA-Placeholder-14.10.2018-.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/earbook.online\/pora\/wp-content\/uploads\/2018\/10\/PORA-Placeholder-14.10.2018-.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/earbook.online\/pora\/wp-content\/uploads\/2018\/10\/PORA-Placeholder-14.10.2018-.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/earbook.online\/pora\/wp-content\/uploads\/2018\/10\/PORA-Placeholder-14.10.2018-.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":3676,"url":"https:\/\/earbook.online\/pora\/blog\/2019\/02\/forum-discussion-boosting-hearing-and-speech-memory-the-games-toolbox-m-guryeva-february-10-2019\/","url_meta":{"origin":2281,"position":2},"title":"Forum discussion: Boosting Hearing and Speech Memory: The Games Toolbox \u2013 M. Guryeva, February 10 2019","author":"","date":"February 5, 2019","format":false,"excerpt":"","rel":"","context":"In "PORA ! For parents"","block_context":{"text":"PORA ! For parents","link":"https:\/\/earbook.online\/pora\/blog\/category\/pora-for-parents\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":3950,"url":"https:\/\/earbook.online\/pora\/blog\/2019\/05\/forum-discussion-post-operative-hearing-and-speech-therapy-after-a-ci-are-aural-speech-and-sign-language-mutually-exclusive-bodo-bertram-may-19-2019\/","url_meta":{"origin":2281,"position":3},"title":"Forum discussion: Post-operative hearing and speech therapy after a CI: are aural speech and sign language mutually exclusive? \u2013 Bodo Bertram, May 19 2019","author":"Michael Goriany","date":"May 5, 2019","format":false,"excerpt":"","rel":"","context":"In "PORA ! For parents"","block_context":{"text":"PORA ! For parents","link":"https:\/\/earbook.online\/pora\/blog\/category\/pora-for-parents\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.lehnhardt-akademie.net\/weblog\/wp-content\/uploads\/2019\/05\/PORA-Placeholder-19.05.2019-1-1.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.lehnhardt-akademie.net\/weblog\/wp-content\/uploads\/2019\/05\/PORA-Placeholder-19.05.2019-1-1.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/www.lehnhardt-akademie.net\/weblog\/wp-content\/uploads\/2019\/05\/PORA-Placeholder-19.05.2019-1-1.jpg?resize=525%2C300 1.5x"},"classes":[]},{"id":8666,"url":"https:\/\/earbook.online\/pora\/blog\/2023\/02\/fd_oecig\/","url_meta":{"origin":2281,"position":4},"title":"PORA! 26.02. Forum-Discussion with Tobias Fischer","author":"Michael Goriany","date":"February 20, 2023","format":false,"excerpt":"We would like to invite you to the Forum-Discussion PORA! on February 26 at 15.00\u00a0 Berlin time (CET). Topic \"My journey into the world of hearing\" is presented by Tobias Fischer from Austria. He will also\u00a0 answer your questions. Tobias received his first CI in 1988 and was the first\u2026","rel":"","context":"In "news"","block_context":{"text":"news","link":"https:\/\/earbook.online\/pora\/blog\/category\/news-en\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":9444,"url":"https:\/\/earbook.online\/pora\/blog\/2025\/04\/flyer-emma-rushbrooke-audiology-in-avt-copy\/","url_meta":{"origin":2281,"position":5},"title":"Copy of Flyer Emma Rushbrooke – Audiology in AVT","author":"Michael Goriany","date":"April 2, 2025","format":false,"excerpt":"PORA ! ONLINE SONNTAGS SCHULE https:\/\/lehnhardt-stiftung.org DO NOT MISS THIS UNIQUE OPPORTUNITY!!! Emma Rushbrooke\u00a0MPhil (Audiology), BA, DipAud, MAudSA, LSLS Cert AVT, RNC Clinical Director, Hear and Say, Australia AG Bell Academy Chairperson Emma Rushbrooke, one of the most experienced audiologists from Australia with over 22 years\u00a0working with children with hearing\u2026","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/earbook.online\/pora\/wp-content\/uploads\/2025\/03\/logo_lehnhardt-stiftung-neu_v1pica-300x147.png?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]}],"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/paKxm9-AN","_links":{"self":[{"href":"https:\/\/earbook.online\/pora\/wp-json\/wp\/v2\/posts\/2281","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/earbook.online\/pora\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/earbook.online\/pora\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/earbook.online\/pora\/wp-json\/wp\/v2\/users\/506"}],"replies":[{"embeddable":true,"href":"https:\/\/earbook.online\/pora\/wp-json\/wp\/v2\/comments?post=2281"}],"version-history":[{"count":4,"href":"https:\/\/earbook.online\/pora\/wp-json\/wp\/v2\/posts\/2281\/revisions"}],"predecessor-version":[{"id":2631,"href":"https:\/\/earbook.online\/pora\/wp-json\/wp\/v2\/posts\/2281\/revisions\/2631"}],"wp:attachment":[{"href":"https:\/\/earbook.online\/pora\/wp-json\/wp\/v2\/media?parent=2281"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/earbook.online\/pora\/wp-json\/wp\/v2\/categories?post=2281"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/earbook.online\/pora\/wp-json\/wp\/v2\/tags?post=2281"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}