title: Localization of Usher syndrome type II to chromosome 1q.
abstract: Usher syndrome is characterized by congenital hearing loss, progressive visual impairment due to retinitis pigmentosa, and variable vestibular problems. The two subtypes of Usher syndrome, types I and II, can be distinguished by the degree of hearing loss and by the presence or absence of vestibular dysfunction. Type I is characterized by a profound hearing loss and totally absent vestibular responses, while type II has a milder hearing loss and normal vestibular function. Fifty-five members of eight type II Usher syndrome families were typed for three DNA markers in the distal region of chromosome 1q: D1S65 (pEKH7.4), REN (pHRnES1.9), and D1S81 (pTHH33). Statistically significant linkage was observed for Usher syndrome type II with a maximum multipoint lod score of 6.37 at the position of the marker THH33, thus localizing the Usher type II (USH2) gene to 1q. Nine families with type I Usher syndrome failed to show linkage to the same three markers. The statistical test for heterogeneity of linkage between Usher syndrome types I and II was highly significant, thus demonstrating that they are due to mutations at different genetic loci.
authors.affiliation: Center for Hereditary Communication Disorders, Boys Town National Research Hospital, Omaha, Nebraska 68131.
authors.forename: W J
authors.initials: WJ
authors.lastname: Kimberling
authors.forename: M D
authors.initials: MD
authors.lastname: Weston
authors.forename: C
authors.initials: C
authors.lastname: Möller
authors.forename: S L
authors.initials: SL
authors.lastname: Davenport
authors.forename: Y Y
authors.initials: YY
authors.lastname: Shugart
authors.forename: I A
authors.initials: IA
authors.lastname: Priluck
authors.forename: A
authors.initials: A
authors.lastname: Martini
authors.forename: M
authors.initials: M
authors.lastname: Milani
authors.forename: R J
authors.initials: RJ
authors.lastname: Smith
mesh_terms: D002874:Chromosome Mapping; D002878:Chromosomes, Human, Pair 1; D005260:Female; D006311:Hearing Disorders / Q000235:genetics*; D006801:Humans; D008126:Lod Score; D008297:Male; D010375:Pedigree; D012174:Retinitis Pigmentosa / Q000235:genetics*; D013577:Syndrome