The process of syndrome delineation and the heterogeneity of hearing loss

Conductive, sensorineural, or mixed hearing loss may occur alone or together with various other abnormalities making up a large number of different syndromes. Hearing loss is also known to occur with various percentages in different syndromes. The process of syndrome delineation is illustrated using syndromes with hearing loss as examples. As an unknown syndrome becomes delineated, its phenotypic spectrum, its natural history, and its inheritance pattern or risk of recurrence become known, allowing for better patient care and family counseling.