Non-syndromic sensorineural prelingual deafness: the importance of genetic counseling in demystifying parents' beliefs about the cause of their children's deafness.

Recent advances in molecular genetics have allowed the determination of the genetic cause of some childhood non-syndromic deafness. In Portugal only a small proportion of families are referred to a clinical genetics service in order to clarify the etiology of the deafness and to provide genetic counseling. Consequently, there are no published studies of the prior beliefs of parents about the causes of hereditary deafness of their children and their genetic knowledge after receipt of genetic counseling. In order to evaluate the impact of genetic counseling, 44 parents of 24 children with the diagnosis of non-syndromic sensorineural prelingual deafness due to mutations in the GJB2 (connexin 26), completed surveys before and after genetic counseling. Before counseling 13.6 % of the parents knew the cause of deafness; at a post-counseling setting this percentage was significantly higher, with 84.1 % of the parents accurately identifying the etiology. No significant differences were found between the answers of mothers and fathers either before or after genetic counseling. Parents' level of education was a significant factor in pre-test knowledge. After genetic counseling 95.5 % of the parents stated that the consultation had met their expectations, 70.5 % remembered correctly the inheritance pattern, and 93.2 % correctly recalled the chance of risk of deafness. These results underline the importance of genetic counseling in demystifying parents' beliefs about the etiology of their children's deafness.