Newborn hearing screening and genetic testing in 8974 Brazilian neonates

An early diagnosis has been a priority in the audiological practice. Identifying hearing loss until 3 months old through Universal Newborn Hearing Screening and intervention before 6 months old, minimize the impact of auditory loss in the health and communication development of these children. However, in the clinical practice, despite the help of the risk indicators in the audiological and etiological diagnosis, the integrated services have come up against the challenge of determining the causes of auditory loss, bearing in mind that approximately 50% of the subjects who have congenital loss do not show risk factors in their clinical history. The current research aims introduce together etiologic and audiological diagnosis of newborns.

We eluted dried blood spots from paper and performed genetic testing for 35delG mutation in 8974 newborns that were also screened for transient otoacoustic emissions (TOAE). In addition, the A1555G and A827G mutations in the MTRNR1 mitochondrial gene were screened in all newborns.

We have found 17 individuals who failed in TOAE. Among them, we detected 4 homozygous newborns for 35delG mutation and 3 individuals with A827G mutation in the MTRNR1 mitochondrial gene. The frequency of 35delG carriers was 0.94% [84/8974]. In all 17 individuals who failed in OAE no other mutation besides those mentioned above was found.

The results greatly contribute to the public health area indicating the etiologic diagnosis, allowing family counseling as well as the early rehabilitation treatment or surgical intervention. Over time that will help to reduce the costs of rehabilitation considerably.