Sensory hearing loss with onset during adult life is often familial The mode of inheritance may be either autosomal dominant or recessive The age at onset, the rate of progression of hearing loss, and the audiometric pattern (high frequency, low-frequency, or flat) can often be predicted by studying family members The connexin-26 mutation, the most common cause of genetic deafness, may be tested clinically, as can most other single gene mutations known to cause hearing loss