Inherited deafness in childhood--the genetic revolution unmasks the clinical challenge.

Approximately one child per 1000 is diagnosed with severe, profound, or early onset hearing impairment, of whom approximately 50% are thought to have a genetic cause. 2 Associated clinical findings, if present and recognised neonatally, often facilitate the identification of a syndrome and the prediction that a hearing problem is likely to be part of the clinical profile. While the presence of such findings aVords the recognition of an underlying syndromic diagnosis in up to 30% of hearing impaired individuals, in most children with hearing impairment there are no other clinical findings—that is, the hearing loss is nonsyndromic. As most such cases are transmitted in autosomal recessive manner, the finding of hearing loss in the aVected child is unexpected, often delayed and, in addition to the obvious social and educational implications, frequently accompanied by parental anxiety for subsequent born siblings or ongoing pregnancies. Faced with such clinical tensions, the paediatrician may rightly wonder whether the recent molecular advances in the genetics of deafness might not benefit hearing impaired patients and their families.