Usher syndrome is a clinically and genetically heterogeneous autosomal recessive disorder characterized by sensorineural hearing deficiencies at birth and later development of progressive retinitis pigmentosa (RP). It is the most frequent cause of combined deafness and blindness in adults and affects 3 to 6% of children born with hearing impairment. In brief, patients with Usher syndrome type II have mild hearing impairment with normal vestibular responses. Type II is the most common of the 3 Usher syndromes. [From OMIM]
Saouda et al. (1998) conducted segregation analysis on five Lebanese families affected with Usher Syndrome. They were able to narrow the USH2 locus to an interval between D1S2646/D1S2629 and D1S2827.