Review Article

An Update on the Genetics of Usher Syndrome

Table 2

Genetic classification of Usher syndrome.

LocusLocationGene/proteinFunction

USH1B/DFNB2/DFNA111q13.5MYO7A/myosin VIIAIE and R: transport
USH1C/DFNB1811p15.1USH1C/harmoninIE and R: scaffolding
USH1D/DFNB1210q22.1CDH23/cadherin 23IE: tip link formation; R: periciliary maintenance
USH1E21q21−/−Unknown
USH1F/DFNB2310q21.1PCDH15/protocadherin 15IE: tip link formation; R: periciliary maintenance
USH1G17q25.1USH1G/SANSIE and R: scaffolding and protein trafficking
USH1H15q22-23−/−Unknown
USH2A/RP1q41USH2A/usherinIE: ankle links formation and cochlear development; R: periciliary maintenance
USH2C5q14.3GPR98/VLGR1IE: ankle links formation Cochlear development; R: periciliary maintenance
USH2D/DFNB319q32-34DFNB31/whirlinIE: scaffolding and cochlear development; R: scaffolding
USH3A3q25.1USH3A/clarin-1IE and R: probable role in synapsis transport*
USH3B20q−/−Unknown

USH: usher syndrome; DFNB: autosomal recessive deafness; DFNA: autosomal dominant deafness; RP: retinitis pigmentosa; IE: inner ear; R: retina.
*A role in the retinal and inner ear synapses as been proposed for all the USH proteins. This remains to be elucidated.