17have normal hearing parents! Recessive Inheritance 90% of all children w/HLhave normal hearing parents!Dominant InheritanceRecessive InheritanceParent w/o HLParent w/HLParent w/o HLChild w/HLChild w/ HLIf a parent has a dominantmutation, EACH of their childrenhas a 50% chance of havinghearing lossIf two parents have a recessivemutation, EACH of their childrenhas a 25% chance of havinghearing loss
21WHO Should Have a Genetic Test? Everybody with Sensorineural HLCase A: SyphilisCase B: CMVCase C: PrematurityCase D: High bilirubin levelAlso 2 Mutations in Cx26!!
22WHY Should We Have a Genetic Test?? Benefits for Genetic Testinga definite causefamily members realize that they are carriers & determine risk factors for future childrenhelps to find appropriate treatment/ management
23Limitations for Genetic Testing does not necessarily find the answerseverity of HL may not be predicteda person may have mutations, but not have HL
24Things to Consider Talk to knowledgeable professional Primary Care/ PediatricianENTAudiologistClinical GeneticistGenetic CounselorClinical Molecular Geneticist
25Things to Consider 2. What tests are done? 3. Cost Cx26 Cx30 Mitochondrial TestsPendred3. Cost
27What Does the Result Mean? Two Mutations are FoundNo Mutations are Found~18%~70%Mutations w/Unknown SignificanceOne Mutation is Found~10%~1%??
28One Mutation Found Mutation unrelated to deafness Test did not find 2nd mutationDominant mutationThere may be a mutation in another gene
29Future in Genetics and HL More Genetic TestsGeneChip Technology
30Research 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 questionnaireGeneChip Study - individuals with hearing loss who and parents with normal hearingNovel Gene Discovery Study - five or more family members with hearing loss
32Helpful InformationGenetic Counselor - Rebecca Madore call to set an appointment orDepartment of Clinical Genetics – To make appointment with Clinical Geneticist callNational Society of Genetic Counselors (NSGC)Research Study Participation & Booklets Orders:Anna Frangulovor