Usher syndrome: Genetic diagnosis and current therapeutic approaches

Table 1 Comparison between Usher syndrome types and symptoms

Type	Hearing loss	Vision loss	Vestibular function
Type 1	Profound bilateral hearing loss at birth[26,149]	Earlier onset, in the first decade of life[13,26]	Vestibular areflexia at birth[26]
Type 2	Moderate to severe hearing loss at birth[13,24]	Late childhood or teens[26]	Normal[44]
Type 3	Normal at birth, with progressive loss[28,164]	Commonly in early youth[13,26]	Variable[38]