A healthy 18-month-old girl fails her newborn hearing screen and subsequent audiology testing confirms bilateral, severe-to-profound sensorineural hearing loss. There is no family history of hearing loss, and the pregnancy was uncomplicated. Genetic testing reveals that she is homozygous for the 35delG mutation (35delG/35delG genotype) in the GJB2 gene. How should the parents be counseled regarding her prognosis?