usher syndromes

Usher syndrome, also known as Hallgren syndrome, Usher–Hallgren syndrome, retinitis pigmentosa–dysacusis syndrome or dystrophia retinae dysacusis syndrome, is a rare genetic disorder caused by a mutation in any one of at least 11 genes resulting in a combination of hearing loss and visual impairment. It is a major cause of deafblindness and is at present incurable.

Usher syndrome is classed into three subtypes (I, II and III) according to the genes responsible and the onset of deafness. All three ...