USH2A and Usher syndrome: ,4 Approximately two-thirds of all Usher patients have USH2, of which up to 85% can be explained by pathogenic variants in the USH2A gene.5, 6, 7 Besides hearing impairment and vision loss, comorbidities like olfactory deficits and deficits in tactile perception have also been associated with USH.8, 9, 10, 11 In addition, patients often report fatigue and sleep problems that severely impact their quality of life.