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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. |
- Kimberling, William J., et al.
(författare)
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Localization of Usher syndrome type II to chromosome 1q
- 1990
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Ingår i: Genomics. - : Elsevier BV. - 0888-7543 .- 1089-8646. ; 7:2, s. 245-249
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Tidskriftsartikel (refereegranskat)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.
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| 4. |
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| 5. |
- Lagerström-Fermér, Maria, et al.
(författare)
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Amelogenin signal peptide mutation : correlation between mutations in the amelogenin gene (AMGX) and manifestations of X-linked amelogenesis imperfecta
- 1995
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Ingår i: Genomics. - : Elsevier BV. - 0888-7543 .- 1089-8646. ; 26:1, s. 159-162
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Tidskriftsartikel (refereegranskat)abstract
- Formation of tooth enamel is a poorly understood biological process. In this study we describe a 9-bp deletion in exon 2 of the amelogenin gene (AMGX) causing X-linked hypoplastic amelogenesis imperfecta, a disease characterized by defective enamel. The mutation results in the loss of 3 amino acids and exchange of 1 in the signal peptide of the amelogenin protein. This deletion in the signal peptide probably interferes with translocation of the amelogenin protein during synthesis, resulting in the thin enamel observed in affected members of the family. We compare this mutation to a previously reported mutation in the amelogenin gene that causes a different disease phenotype. The study illustrates that molecular analysis can help explain the various manifestations of a tooth disorder and thereby provide insights into the mechanisms of tooth enamel formation.
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| 7. |
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| 8. |
- Syvänen, Ann-Christine, et al.
(författare)
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A primer-guided nucleotide incorporation assay in the genotyping of apolipoprotein E
- 1990
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Ingår i: Genomics. - 0888-7543 .- 1089-8646. ; 8:4, s. 684-692
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Tidskriftsartikel (refereegranskat)abstract
- We describe a new technique by which single base changes in human genes can be conveniently detected. In this method the DNA fragment of interest is first amplified using the polymerase chain reaction with an oligonucleotide primer biotinylated at its 5'-end. The amplified 5'-biotinylated DNA is immobilized on an avidin matrix and rendered single-stranded. The variable nucleotide in the immobilized DNA is identified by a one-step primer extension reaction directed by a detection step primer, which anneals to the DNA immediately upstream of the site of variation. In this reaction a single labeled nucleoside triphosphate complementary to the nucleotide at the variable site is incorporated. The method is highly sensitive, allowing the use of nucleoside triphosphates labeled with radioisotopes of low specific activity (3H) as well as nonradioactive markers (digoxigenin). The procedure consists of few and simple operations and is thus applicable to the analysis of large numbers of samples. Here we applied it to the analysis of the three-allelic polymorphism of the human apolipoprotein E gene. We were able to correctly identify all possible combinations of the three apo E alleles.
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| 9. |
- Syvänen, Ann-Christine, et al.
(författare)
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Convenient and quantitative determination of the frequency of a mutant allele using solid-phase minisequencing : application to aspartylglucosaminuria in Finland
- 1992
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Ingår i: Genomics. - 0888-7543 .- 1089-8646. ; 12:3, s. 590-595
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Tidskriftsartikel (refereegranskat)abstract
- Aspartylglucosaminuria (AGU) is a recessively inherited lysosomal disease caused by inadequate aspartylglucosaminidase (AGA) activity. The disease is prevalent in the genetically isolated Finnish population. We have used a new method, solid-phase minisequencing, to determine the frequency of two missense mutations in the AGA gene in this population. In samples from 70% of the Finnish AGU families, we found that the two nucleotide changes were always associated, and they were identified in 98% of the AGU alleles analyzed. Thus, the high prevalence of AGU in the Finnish population is the consequence of a founder effect of one ancient mutation. The identification of asymptomatic carriers by the minisequencing test proved to be unequivocal. The method also allowed quantification of a mutated nucleotide sequence present in less than 1% of a sample. The frequency of AGU carriers in this population was 1/36 when estimated by quantifying the mutated AGU allele in a pooled leukocyte sample from 1350 normal Finnish individuals.
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| 10. |
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