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What Is In Your Genes?

What Is In Your Genes?. Anna Frangulov, B.S. Research Coordinator Children’s Hospital Boston. Why Hearing Loss is So Common?. Structure of the Ear. Sound wave. Hair Cell the Cochlea “snail”. Extensions. Hair Cell. Structure of the Ear. Sensorineural HL . Conductive HL.

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What Is In Your Genes?

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  1. What Is In Your Genes? Anna Frangulov, B.S. Research Coordinator Children’s Hospital Boston

  2. Why Hearing Loss is So Common?

  3. Structure of the Ear

  4. Sound wave Hair Cell the Cochlea “snail” Extensions Hair Cell

  5. Structure of the Ear Sensorineural HL Conductive HL

  6. What Causes Hearing Loss? • Infections Non-Genetic • Drug-Related • Traumas/ • Exposures • Structural Genetic • Unknown

  7. How Genetic HL occurs?

  8. Chromosomes in Nucleus 23 Pairs of Chromosomes MOM DAD

  9. One Chromosome Pair Genes “instruction manual”

  10. Genes

  11. Chromosome Pair Genes Mutation “error”

  12. How Is Mutation Passed On (Inherited)? • Recessive ~80% • Dominant ~15% • X-Linked ~2% • Mitochondrial >2%

  13. Dominant Inheritance Hearing Loss Hearing Mutation “error" Hearing Loss Hearing Loss Hearing Hearing

  14. Point #1 The risk rate is for everychild

  15. Carrier Mutation “error" Hearing

  16. How a Recessive Mutation is Passed? Carrier –No Hearing Loss Carrier –No Hearing Loss Affected Child— Hearing Loss

  17. Recessive Inheritance Hearing Hearing Hearing Loss Hearing Hearing Hearing

  18. Point #2 Most children with genetic cause of hearing loss are born to parents with normal hearing

  19. Sex Chromosomes Hearing Hearing Loss

  20. X-Linked Inheritance HL

  21. Mitochondrial Inheritance Hearing Loss Hearing Loss Hearing Loss Hearing Loss Hearing Loss

  22. Recessive Inheritance Dominant Inheritance Hearing “Carrier” Hearing “Carrier” Hearing Loss Every child has 25% Every child has 50%

  23. Mitochondrial X-Linked Mutation is on X chromosome Mother All males have 50% All children w/HL

  24. HOW? WHO? WHY?

  25. HOW Do We Know if HL is Genetic?

  26. WHOShould Have a Genetic Test? • Case A: Syphilis • Case B: CMV • Case C: Prematurity • Case D: High bilirubin level Everybody with Sensorineural HL Also 2 Mutations in Cx26!!

  27. Point #3 Even if you know your cause for hearing loss, you may also have an underlying genetic cause

  28. WHYShould We Have a Genetic Test??

  29. Benefits • a definite cause • family members realize that they are carriers & determine risk factors for future children • helps to find appropriate treatment/ management

  30. Limitations • does not necessarily find the answer • severity of HL may not be predicted • a person may have mutations, but not have HL

  31. Things to Consider 1.Talk to knowledgeable professional • Primary Care/ Pediatrician • ENT • Audiologist • Clinical Geneticist • Genetic Counselor • Clinical Molecular Geneticist

  32. Things to Consider 3. Cost 2. What tests are done? • Cx26 • Cx30 • Mitochondrial Tests • Pendred

  33. UNDERSTANDING TEST RESULTS(example Cx26)

  34. What Does the Result Mean? Two Mutations are Found No Mutations are Found Mutations w/Unknown Significance One Mutation is Found ~18% ~70% ~10% ~1% ??

  35. One Mutation Found • Mutation unrelated to deafness • Test did not find 2nd mutation • Dominant mutation • There may be a mutation in another gene

  36. Future in Genetics and HL • More Genetic Tests GeneChip Technology Two GeneChips are available right now: Deafness GeneChip (Rehm Study): MYO7A, OTOF, MYO6, USH1C, PRES, TMPRSS3, TMIE, GJB2 Deafness GeneChip (Greinwald Study): MYO7A, OTOF, CHDH23, KCNE1, KCNQ1, PDS, GJB6, GJB2

  37. Things to Remember • Most children with HL are born to parents with normal hearing • The risks rates is for every child • If you have other cause for hearing loss you may also have an underlying genetic cause • A negative genetic test result = inconclusive

  38. Questions?

  39. Research Studies • Connexin 26 Study- individuals with Cx26 mutations • Genetic Testing and Counseling Study - If you or your child has had genetic testing for hearing loss and you are willing to fill out a questionnaire • GeneChip Study - individuals with hearing loss who and parents with normal hearing • Novel Gene Discovery Study - five or more family members with hearing loss

  40. Educational Materials http://hearing.harvard.edu Also in Spanish!

  41. Helpful Information • Genetic Counselor - Rebecca Madore call 617-355-4534 to set an appointment or email rmadore@partners.org • Department of Clinical Genetics – To make appointment with Clinical Geneticist call 617-355-6394. • National Society of Genetic Counselors (NSGC) www.nsgc.org • Help us evaluate educational material • Research Study Participation & Booklets Orders: Anna Frangulov 617-515-2962 or anna.frangulov@childrens.harvard.edu

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