Chromosomes in Nucleus 23 Pairs of Chromosomes MOM DAD
One Chromosome Pair Genes “instruction manual”
Chromosome Pair Genes Mutation “error”
How Is Mutation Passed On (Inherited)? Recessive ~80% Dominant ~15% X-Linked ~2% Mitochondrial >2%
Dominant Inheritance Mutation “error" Hearing Hearing Loss Hearing
Point #1 The risk rate is for every child
Carrier Mutation “error" Hearing
How a Recessive Mutation is Passed? Carrier –No Hearing Loss Affected Child— Hearing Loss
Recessive Inheritance Hearing Loss Hearing
Point #2 Most children with genetic cause of hearing loss are born to parents with normal hearing
Sex Chromosomes Hearing Hearing Loss
X-Linked Inheritance HL
Mitochondrial Inheritance Hearing Loss
Every child has 50% Every child has 25% Dominant Inheritance Recessive Inheritance Hearing Loss Hearing “Carrier”
X-Linked Mitochondrial Mutation is on X chromosome All males have 50% All children w/HL Mother
HOW? WHO? WHY?
HOW Do We Know if HL is Genetic?
WHO Should 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!!
Point #3 Even if you know your cause for hearing loss, you may also have an underlying genetic cause
WHY Should We Have a Genetic Test??
Benefits a definite cause family members realize that they are carriers & determine risk factors for future children helps to find appropriate treatment/ management
does not necessarily find the answer severity of HL may not be predicted a person may have mutations, but not have HL Limitations
Things to Consider Things to Consider Primary Care/ Pediatrician ENT Audiologist Clinical Geneticist Clinical Geneticist Genetic Counselor Clinical Molecular Geneticist 1.Talk to knowledgeable professional
Things to Consider 3. Cost 2. What tests are done? Cx26 Cx30 Mitochondrial Tests Pendred
UNDERSTANDING TEST RESULTS (example Cx26)
What Does the Result Mean? Two Mutations are Found No Mutations are Found Mutations w/Unknown Significance One Mutation is Found ?? ~10% ~70% ~18% ~1%
One Mutation Found Mutation unrelated to deafness Test did not find 2 nd mutation Dominant mutation There may be a mutation in another gene
Future in Genetics and HL More Genetic Tests GeneChip Technology Deafness GeneChip (Rehm Study): MYO7A, OTOF, MYO6, USH1C, PRES, TMPRSS3, TMIE, GJB2 Deafness GeneChip (Greinwald Study): MYO7A, OTOF, CHDH23, KCNE1, KCNQ1, PDS, GJB6, GJB2 Two GeneChips are available right now:
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
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
Also in Spanish! Educational Materials
Helpful Information Genetic Counselor - Rebecca Madore call to set an appointment or Department of Clinical Genetics – To make appointment with Clinical Geneticist call National Society of Genetic Counselors (NSGC) Help us evaluate educational material Research Study Participation & Booklets Orders: Anna Frangulov or or