| 1. |
- Kimberling, W. J., et al.
(författare)
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Genetic studies of Usher syndrome
- 1991
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Ingår i: Annals of the New York Academy of Sciences. - : Wiley. - 0077-8923 .- 1749-6632. ; 630:1, s. 167-175
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Kimberling, W. J., et al.
(författare)
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Linkage of Usher syndrome type I gene (USH1B) to the long arm of chromosome 11
- 1992
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Ingår i: Genomics. - 0888-7543 .- 1089-8646. ; 14:4, s. 988-994
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Tidskriftsartikel (refereegranskat)abstract
- Usher syndrome is the most commonly recognized cause of combined visual and hearing loss in technologically developed countries. There are several different types and all are inherited in an autosomal recessive manner. There may be as many as five different genes responsible for at least two closely related phenotypes. The nature of the gene defects is unknown, and positional cloning strategies are being employed to identify the genes. This is a report of the localization of one gene for Usher syndrome type I to chromosome 11q, probably distal to marker D11S527. Another USH1 gene had been previously localized to chromosome 14q, and this second localization establishes the existence of a new and independent locus for Usher syndrome.
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| 3. |
- Pieke-Dahl, S., et al.
(författare)
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Genetic heterogeneity of Usher syndrome type II : localisation to chromosome 5q
- 2000
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Ingår i: Journal of Medical Genetics. - : BMJ. - 0022-2593 .- 1468-6244. ; 37:4, s. 256-262
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Tidskriftsartikel (refereegranskat)abstract
- Usher syndrome is a group of autosomal recessive disorders that includes retinitis pigmentosa (RP) with hearing loss. Usher syndrome type II is defined as moderate to severe hearing loss with RP. TheUSH2A gene at 1q41 has been isolated and characterised. In 1993, a large Usher II family affected with a mild form of RP was found to be unlinked to 1q41 markers. Subsequent linkage studies of families in our Usher series identified several type II families unlinked to USH2A andUSH3 on 3q25. After a second unlinked family with many affected members and a mild retinal phenotype was discovered, a genome search using these two large families showed another Usher II locus on 5q (two point lod = 3.1 at D5S484). To date, we have identified nine unrelated 5q linked families (maximum combined multipoint lod = 5.86) as well as three Usher II families that show no significant linkage to any known Usher loci. Haplotype analysis of 5q markers indicates that the new locus is flanked by D5S428 and D5S433. Review of ophthalmological data suggests that RP symptoms are milder in 5q linked families; the RP is often not diagnosed until patients near their third decade. Enamel hypoplasia and severe, very early onset RP were observed in two of the three unlinked families; dental anomalies have not been previously described as a feature of Usher type II.
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| 4. |
- Pieke Dahl, S, et al.
(författare)
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Genetic heterogeneity of Usher syndrome type II
- 1993
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Ingår i: Journal of Medical Genetics. - : BMJ Group. - 0022-2593 .- 1468-6244. ; 30:10, s. 843-848
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Tidskriftsartikel (refereegranskat)abstract
- Usher syndrome is an autosomal recessive disorder characterised by retinitis pigmentosa and congenital sensorineural hearing loss. A gene for Usher syndrome type II (USH2) has been localised to chromosome 1q32-q41. DNA from a family with four of seven sibs affected with clinical characteristics of Usher syndrome type II was genotyped using markers spanning the 1q32-1q41 region. These included D1S70 and D1S81, which are believed to flank USH2. Genotypic results and subsequent linkage analysis indicated non-linkage of this family to these markers. The A test analysis for heterogeneity with this family and 32 other Usher type II families was statistically significant at p < 0.05. Further clinical evaluation of this family was done in light of the linkage results to determine if any phenotypic characteristics would allow for clinical identification of the unlinked type. No clear phenotypic differences were observed; however, this unlinked family may represent a previously unreported subtype of Usher type II characterised by a milder form of retinitis pigmentosa and mild vestibular abnormalities. Heterogeneity of Usher syndrome type II complicates efforts to isolate and clone Usher syndrome genes using linkage analysis and limits the use of DNA markers in early detection of Usher type II.
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| 5. |
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