| 1. |
- Almqvist, E, et al.
(författare)
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Ancestral differences in the distribution of the delta 2642 glutamic acid polymorphism is associated with varying CAG repeat lengths on normal chromosomes : insights into the genetic evolution of Huntington disease.
- 1995
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 4:2, s. 207-14
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Tidskriftsartikel (refereegranskat)abstract
- This study addresses genetic factors associated with normal variation of the CAG repeat in the Huntington disease (HD) gene. To achieve this, we have studied patterns of variation of three trinucleotide repeats in the HD gene including the CAG and adjacent CCG repeats as well as a GAG polymorphism at residue 2642 (delta 2642). We have previously demonstrated that variation in the CCG repeat is associated with variation of the CAG repeat length on normal chromosomes. Here we show that differences in the GAG trinucleotide polymorphism at residue 2642 is also significantly correlated with CAG size on normal chromosomes. The B allele which is associated with higher CAG repeat lengths on normal chromosomes is markedly enriched on affected chromosomes. Furthermore, this glutamic acid polymorphism shows significant variation in different ancestries and is absent in chromosomes of Japanese, Black and Chinese descent. Haplotype analysis of both the CCG and delta 2642 polymorphisms have indicated that both are independently associated with differences in CAG length on normal chromosomes. These findings lead to a model for the genetic evolution of new mutations for HD preferentially occurring on normal chromosomes with higher CAG repeat lengths and a CCG repeat length of seven and/or a deletion of the glutamic acid residue at delta 2642. This study also provides additional evidence for genetic contributions to demographic differences in prevalence rates for HD.
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| 2. |
- Bondeson, Marie-Louise, et al.
(författare)
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Inversion of the IDS gene resulting from recombination with IDS-related sequences is a common cause of the Hunter syndrome
- 1995
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Ingår i: Human Molecular Genetics. - 0964-6906 .- 1460-2083. ; 4:4, s. 615-621
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Tidskriftsartikel (refereegranskat)abstract
- We have recently described the identification of a second IDS locus (IDS-2) located within 90 kb telomeric of the IDS gene (Bondeson et al. submitted). Here, we show that this region is involved in a recombination event with the IDS gene in about 13% of patients with the Hunter syndrome. Analysis of the resulting rearrangement at the molecular level showed that these patients have suffered a recombination event that results in a disruption of the IDS gene in intron 7 with an inversion of the intervening DNA. Interestingly, all of the six cases with a similar type of rearrangement showed recombination between intron 7 of the IDS gene and sequences close to exon 3 at the IDS-2 locus implying that these regions are hot spots for recombination. Analysis by nucleotide sequencing showed that the inversion is caused by recombination between homologous sequences present in the IDS gene and the IDS-2 locus. No detectable deletions or insertions were observed as a result of the recombination event. The results in this study have practical implications for diagnosis of the Hunter syndrome.
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| 3. |
- Goldberg, Y P, et al.
(författare)
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Increased instability of intermediate alleles in families with sporadic Huntington disease compared to similar sized intermediate alleles in the general population.
- 1995
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 4:10, s. 1911-8
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Tidskriftsartikel (refereegranskat)abstract
- We have directly compared intergenerational stability of intermediate alleles (IAs) derived from new mutation families (IANM) for Huntington disease (HD) with IAs in the general population (IAGP) which occur in approximately 1 in 50 persons. Analysis of meiotic events in blood and sperm reveals that IANM are significantly more unstable than IAGP despite similar size. However, for both IANM and IAGP CAG changes were small and risks for inheriting an expansion into the HD affected range were low. Sequence analysis reveals that the CAG tract is generally interrupted by a penultimate CAA in IAGP, IANM and alleles in the affected range. In one new mutation family, however, two A-->G mutations result in a pure CAG tract which is associated with very marked instability. These mutations alter the predicted DNA hairpin structure with a predicted increase in the likelihood of large expansion, supporting the model that hairpin loop formation plays an important role in trinucleotide instability.
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| 4. |
- Holmberg, Monica, et al.
(författare)
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Localization of autosomal dominant cerebellar ataxia associated with retinal degeneration and anticipation to chromosome 3p12-p21.1
- 1995
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 4:8, s. 1441-1445
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Tidskriftsartikel (refereegranskat)abstract
- We present linkage analysis on a large Swedish five-generation family of 15 affected individuals with autosomal dominant cerebellar ataxia (ADCA) associated with retinal degeneration and anticipation, Common clinical signs in this family include ataxia, dysarthria and severely impaired vision with the phenotype ADCA type II, Different subtypes of ADCA have proven difficult to classify clinically due to extensive phenotypic variability within and between families. Genetic analysis of a number of ADCA type I families shows that heterogeneity exists also genetically, During the last few years several types of ADCA type I have been localized and to date six genetically distinct forms have been identified including SCA1 (6p), SCA2 (12q), SCA3 and Machado-Joseph disease (MJD) (14q), SCA4 (16q), and finally SCA5 (11), We performed a genome-wide search of the Swedish ADCA type II family using a total of 270 microsatellite markers, Positive lod scores were obtained with a number of microsatellite markers located on chromosome 3p12-p21.1. Three markers gave lod scores over 3 with a maximum lod score of 4.53 achieved with the marker D3S1600. The ADCA type II gene could be restricted to a region of 32 cM by the markers D3S1547 and D3S1274.
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| 5. |
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| 6. |
- Lind, L, et al.
(författare)
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Localization of the gene for congenital dyserythropoietic anemia type III, CDAN3, to chromosome 15q21-q25.
- 1995
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Ingår i: Human Molecular Genetics. - 0964-6906 .- 1460-2083. ; 4:1, s. 109-12
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Tidskriftsartikel (refereegranskat)abstract
- Congenital dyserythropoietic anemia, type III (CDA III) is a rare autosomal dominant disorder characterized by macrocytic anemia, bone marrow erythroid hyperplasia and giant multinucleate erythroblasts. We have genetically characterized a large Swedish family in which the concurrence of CDA III and myeloma or benign monoclonal gammopathy is significantly higher than expected and have found that the causative genetic defect for CDA III maps to an 11 cM interval within 15q21-q25.
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