Dodson et al. (2007) reported 2 unrelated cases of possible familial unilateral deafness with delayed endolymphatic hydrops. One patient was a 38-year-old man with severe to profound hearing loss in the left ear since childhood, who at 36 ... Dodson et al. (2007) reported 2 unrelated cases of possible familial unilateral deafness with delayed endolymphatic hydrops. One patient was a 38-year-old man with severe to profound hearing loss in the left ear since childhood, who at 36 years of age developed episodic fluctuating hearing loss in the right ear and aural fullness, without vertigo or tinnitus. His symptoms were controlled with a low-salt diet and diuretics. His maternal grandfather had lifelong unilateral hearing loss, which progressed to bilateral hearing loss later in life, similar to that of the proband. A maternal uncle also had childhood-onset unilateral hearing loss that progressed to bilateral loss. The second patient was a 6-year-old girl who had rapid onset of severe to profound hearing loss in her left ear. Her maternal grandfather, who had unilateral hearing loss since childhood, had developed vertigo associated with tinnitus and aural fullness at 50 years of age. CT scan of the temporal bone showed no abnormality in either proband. Dodson et al. (2007) concluded that some cases of delayed endolymphatic hydrops may be caused by genetic factors.