[Genetic counseling and intervention for families with deaf-mute patients based on genetic testing: analysis of 5 families].

OBJECTIVE: To analyze the molecular genetic mechanisms of pathogenesis of deafness in the families with deaf-mute patients and analyze the strategies of genetic counseling and intervention for these families. METHODS: Peripheral blood samples were collected from the probands with deaf-muteness and their parents of five families and genetic tests were conducted to analyze the GJB2, SLC26A4 (PDS), and mitochondrial DNA (mtDNA) A 1555G genes for the existence of mutation. Families 1-3 had one child with hearing loss each while the parents had normal hearing and the mothers had been pregnant for 6-18 weeks. Both parents of family 4 were deaf-mute, and the wife of family 5 was deaf-mute while her husband had normal hearing. RESULTS: The proband from family 1 was proven to carry compound GJB2 mutations while his parents carried a single GJB2 mutation; prenatal testing showed that the fetus only carried the paternal mutation. The proband from family 2 was proven to carry compound SLC26A4 (PDS) mutations while his parents carried a single SLC26A4 (PDS) mutation; prenatal testing showed that the fetus only carried the paternal mutation. The proband from family 3 and his parents didn't carry any GJB2, SLC26A4 and mtDNA A1555G mutation. Observation showed that the new born babies of these three families all had normal hearing revealed by new born hearing screening and ABR test. The husband from family 4 was homozygous GJB2 235delC while his wife was mtDNA A1555G positive. This couple was advised to strictly avoid the administration of aminoglycoside antibiotics to their future offspring. In family 5, the wife carried compound SLC26A4 (PDS) mutations while her husband carried a single SLC26A4 (PDS) mutation; and they were told about the 50% risk of their offspring's suffering from enlarged vestibular aqueduct syndrome. CONCLUSION: Genetic testing with prenatal testing and relevant intervention for the families with deaf-mute patients can be applied to prevent another deaf-mute member from being born.