USH2A and sensorineural hearing loss disorder: For example, in a recent study of the USH2A gene, the most frequent cause of Usher syndrome type II (USH2) involving RP and sensorineural hearing loss, an analysis of the whole 800kb of the USH2A gene was prompted by the identification of patients with an USH2 phenotype and a single exonic mutation in the USH2A gene.