Overview of genetic auditory syndromes.

Accurate determination of the cause of hearing loss is critically important for clinicians for prognosis and management. Recognition of genetic syndromes is especially important, but this is dependent upon clear delineation of the characteristics of the syndromes. Research into underlying mechanisms of hearing loss is also much more effective if the cause of the hearing loss is known to be the same in the subjects being studied. Family studies of hearing loss can be very important in determining the phenotypic range of the condition, but it has become clear that phenotypically similar families may not actually have the same genetic cause. Molecular genetic studies are needed to determine which genes, and even which mutations within genes, are responsible for specific syndromes. This paper reviews the methodology of gene localization (linkage) studies and describes a variety of genetic conditions, syndromic and nonsyndromic, which illustrate the varying relationships between genes, phenotypes, and mechanisms of hearing loss. Knowledge of the cause of hearing loss will facilitate understanding of the auditory system and development of optimum therapy.