Interaction between audiology and genetics in the study of a family: the complexity of molecular diagnosis and genetic counseling.
Hearing loss is a multifaceted condition with many etiologies, among which genetic mutation is. Therefore, it is important to connect audiological investigation to etiological diagnosis.


OBJECTIVE
this study aims to establish the audiological and genetic profiles of three non-syndromic children with sensorineural hearing loss.


METHODS
three brothers aged 3, 5 and 16 were enrolled in this study. They were submitted to behavioral and electrophysiological hearing tests and molecular studies.


RESULTS
the hearing tests showed moderate to moderately severe bilateral symmetric sensorineural hearing loss and an accentuated descending slope. Transient and Distortion Product Otoacoustic emissions were absent in the two younger children. ABR showed a bilateral moderately severe to severe sensorineural hearing loss. P300 showed bilateral normal latencies in the older brother. Molecular tests showed that the two younger children were heterozygote for mutation 35delG on gene GJB2.


CONCLUSIONS
The combination of speech and hearing tests and genetic analysis allows for the etiologic diagnosis of seemingly similar hearing loss cases, which however display different genetic backgrounds. Molecular studies must be comprehensive enough to avoid precipitated diagnosis which may impair genetic counseling.
Hoffmann
Flavia Maria Rodrigues
FMR
Specialist in audiology at Instituto de Estudos Avançados da Audição, IEAA, Brazil. Speech and Hearing Therapist.
Rodrigues
Patrícia Fernandes
PF
PhD in Human Communication Disorders, Speech and Hearing Therapy at Universidade Federal de São Paulo, UNIFESP, Brazil. Speech and Hearing Therapist, Professor in the specialization program on Audiology at Instituto de Estudos da Audição - IEAA.
Dos Santos
Teresa Maria Momensohn
TMM
PhD in Human Communication Disorders, Speech and Hearing Therapy at Universidade Federal de São Paulo, UNIFESP, Brazil. Speech and Hearing Therapist, Full Professor at PUC SP, Director at Instituto de Estudos Avançados da Audição - IEAA.
Sartorato
Edi Lucia
EL
PhD in Genetics and Molecular Biology at Universidade Estadual de Campinas, UNICAMP, Brazil. Researcher at Centro de Biologia Molecular e Engenharia Genética da UNICAMP, Associate Professor of Medical Genetics at UNICAMP.
Maciel-Guerra
Andréa Trevas
AT
PhD in Genetics and Molecular Biology at Universidade Estadual de Campinas, UNICAMP, Brazil. MD, Geneticist, Full Professor at the Medical Genetics Department at Faculdade de Ciências Médicas da UNICAMP.
Matas
Carla Gentile
CG
PhD in Human Communication Disorders, Speech and Hearing Therapy at Universidade Federal de São Paulo, UNIFESP, Brasil. Adjunct Professor in the Speech and Hearing Therapy program at the Department of Physiotherapy, Speech and Hearing Therapy, and Occupational Therapy at Faculdade de Medicina da USP.
de Moraes
Vanessa Cristine Sousa
VCS
Biologist. Scholarship holder on Technical Training at FAPESP's Centro de Biologia Molecular e Engenharia Genética. IEAA - Instituto de Estudos Avançados da Audição.
D000293:Adolescent; D001298:Audiology; D002675:Child, Preschool; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics; D005817:Genetic Counseling; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis* / Q000235:genetics*; D006320:Hearing Tests; D006579:Heterozygote; D006801:Humans; D008297:Male; D009154:Mutation; D017084:Otoacoustic Emissions, Spontaneous; D010375:Pedigree; D010641:Phenotype; D013063:Speech Discrimination Tests
D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26