| 61. |
- Johansson, Asa, et al.
(författare)
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Linkage disequilibrium between microsatellite markers in the Swedish Sami relative to a worldwide selection of populations
- 2005
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Ingår i: Human Genetics. - : Springer Science and Business Media LLC. - 0340-6717 .- 1432-1203. ; 116:1-2, s. 105-13
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Tidskriftsartikel (refereegranskat)abstract
- The pattern of linkage disequilibriurn (LD) is affected by a number of factors, including population dernography. High LD is seen in populations with a relatively limited and constant size, presurnably due to genetic drift. We have examined the extent of LD arnong over 300 genome-wide pattern microsatellite loci in 29 populations from around the world. The pattern of LD vari ed between populations, with larger extent of LO in populations with limited size relative to larger populations. In addition, the LD between 88 less spaced microsatellite ffiarkers from 10 different genornic regions were examined in the Sami compared to the general Swedish population. For the se ffiarkers increased LD extending up to 5 Mb was detected in the Sami. The arnount of LD also differed between the chrornosornal regions. The arnount of LD in the Sami makes this population suited for mapping ofcornplex genetic traits
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| 62. |
- Johansson, Annica, 1969, et al.
(författare)
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Variants of CYP46A1 may interact with age and APOE to influence CSF Abeta42 levels in Alzheimer's disease.
- 2004
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Ingår i: Human genetics. - : Springer Science and Business Media LLC. - 0340-6717 .- 1432-1203. ; 114:6, s. 581-7
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies have suggested that variants of CYP46A1, encoding cholesterol 24-hydroxylase (CYP46), confer risk for Alzheimer's disease (AD), a prospect substantiated by evidence of genetic association from several quantitative traits related to AD pathology, including cerebrospinal fluid (CSF) levels of the 42 amino-acid cleavage product of beta-amyloid (Abeta42) and the tau protein. In the present study, these claims have been explored by the genotyping of previously associated markers in CYP46A1 in three independent northern European case-control series encompassing 1323 individuals and including approximately 400 patients with measurements of CSF Abeta42 and phospho-tau protein levels. Tests of association in case-control models revealed limited evidence that CYP46A1 variants contributed to AD risk across these samples. However, models testing for potential effects upon CSF measures suggested a possible interaction of an intronic marker (rs754203) with age and APOE genotype. In stratified analyses, significant effects were evident that were restricted to elderly APOE epsilon4 carriers for both CSF Abeta42 ( P=0.0009) and phospho-tau ( P=0.046). Computational analyses indicate that the rs754203 marker probably does not impact the binding of regulatory factors, suggesting that other polymorphic sites underlie the observed associations. Our results provide an important independent replication of previous findings, supporting the existence of CYP46A1 sequence variants that contribute to variability in beta-amyloid metabolism.
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| 63. |
- Johansson, Åsa, et al.
(författare)
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A novel method for automatic genotyping of microsatellite markers based on parametric pattern recognition
- 2003
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Ingår i: Human Genetics. - : Springer Science and Business Media LLC. - 0340-6717 .- 1432-1203. ; 113:4, s. 316-324
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Tidskriftsartikel (refereegranskat)abstract
- Genetic mapping of loci affecting complex phenotypes in human and other organisms is presently being conducted on a very large scale, using either microsatellite or single nucleotide polymorphism (SNP) markers and by partly automated methods. A critical step in this process is the conversion of the instrument output into genotypes, both a time-consuming and error prone procedure. Errors made during this calling of genotypes will dramatically reduce the ability to map the location of loci underlying a phenotype. Accurate methods for automatic genotype calling are therefore important. Here, we describe novel algorithms for automatic calling of microsatellite genotypes using parametric pattern recognition. The analysis of microsatellite data is complicated both by the occurrence of stutter bands, which arise from Taq polymerase misreading the number of repeats, and additional bands derived form the non-template dependent addition of a nucleotide to the 3' end of the PCR products. These problems, together with the fact that the lengths of two alleles in a heterozygous individual may differ by only two nucleotides, complicate the development of an automated process. The novel algorithms markedly reduce the need for manual editing and the frequency of miscalls, and compares very favourably with commercially available software for automatic microsatellite genotyping.
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| 64. |
- Johansson, Åsa, et al.
(författare)
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Evaluation of the SNP tagging approach in an independent population sample : Array-based SNP discovery in Sami
- 2007
-
Ingår i: Human Genetics. - : Springer Science and Business Media LLC. - 0340-6717 .- 1432-1203. ; 122:2, s. 141-150
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Tidskriftsartikel (refereegranskat)abstract
- Significant efforts have been made to determine the correlation structure of common SNPs in the human genome. One method has been to identify the sets of tagSNPs that capture most of the genetic variation. Here, we evaluate the transferability of tagSNPs between populations using a population sample of Sami, the indigenous people of Scandinavia. Array-based SNP discovery in a 4.4 Mb region of 28 phased copies of chromosome 21 uncovered 5,132 segregating sites, 3,188 of which had a minimum minor allele frequency (mMAF) of 0.1. Due to the population structure and consequently high LD, the number of tagSNPs needed to capture all SNP variation in Sami is much lower than that for the HapMap populations. TagSNPs identified from the HapMap data perform only slightly better in the Sami than choosing tagSNPs at random from the same set of common SNPs. Surprisingly, tagSNPs defined from the HapMap data did not perform better than selecting the same number of SNPs at random from all SNPs discovered in Sami. Nearly half (46%) of the Sami SNPs with a mMAF of 0.1 are not present in the HapMap dataset. Among sites overlapping between Sami and HapMap populations, 18% are not tagged by the European American (CEU) HapMap tagSNPs, while 43% of the SNPs that are unique to Sami are not tagged by the CEU tagSNPs. These results point to serious limitations in the transferability of common tagSNPs to capture random sequence variation, even between closely related populations, such as CEU and Sami.
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| 65. |
- Johansson, Åsa, et al.
(författare)
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Partial correlation network analyses to detect altered gene interactions in human disease : using preeclampsia as a model
- 2011
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Ingår i: Human Genetics. - : Springer Science and Business Media LLC. - 0340-6717 .- 1432-1203. ; 129:1, s. 25-34
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Tidskriftsartikel (refereegranskat)abstract
- Differences in gene expression between cases and controls have been identified for a number of human diseases. However, the underlying mechanisms of transcriptional regulation remain largely unknown. Beyond comparisons of absolute or relative expression levels, disease states may be associated with alterations in the observed correlational patterns among sets of genes. Here we use partial correlation networks aiming to compare the transcriptional co-regulation for 222 genes that are differentially expressed in decidual tissues between preeclampsia (PE) cases and non-PE controls. Partial correlation coefficients (PCCs) have been calculated in cases (N = 37) and controls (N = 58) separately. For all PCCs, we tested if they were significant non-zero in the cases and controls separately. In addition, to examine if a given PCC is different between the cases and controls, we tested if the difference between two PCCs were significant non-zero. In the group with PE cases, only five PCCs were significant (FDR p value ≤ 0.05), of which none were significantly different from the PCCs in the controls. However, in the controls we identified a total of 56 statistically significant PCCs (FDR p value ≤ 0.05), of which 31 were also significantly different (FDR p value ≤ 0.05) from the PCCs in the PE cases. The identified partial correlation networks included genes that are potentially relevant for developing PE, including both known susceptibility genes (EGFL7, HES1) and novel candidate genes (CFH, NADSYN1, DBP, FIGLA). Our results might suggest that disturbed interactions, or higher order relationships between these genes play an important role in developing the disease.
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| 66. |
- Juvonen, V, et al.
(författare)
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Quantification of point mutations associated with Leber hereditary optic neuroretinopathy by solid-phase minisequencing
- 1994
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Ingår i: Human Genetics. - 0340-6717 .- 1432-1203. ; 93:1, s. 16-20
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Tidskriftsartikel (refereegranskat)abstract
- About two-thirds of patients with Leber hereditary optic neuroretinopathy (LHON) harbor mutations in mitochondrial DNA at positions 11778 (ND4) or 3460 (ND1). Thus, the clinical diagnosis of LHON can often be confirmed with mutation analysis. Detection of pathogenic mutations and quantification of heteroplasmy has mainly relied on PCR and restriction site analysis and densitometric scanning. We applied the recently developed solid-phase minisequencing method, based on primer-guided nucleotide incorporation, to the simultaneous detection and quantitation of the ND4/11778 and ND1/3460 mutations. The method was highly sensitive, heteroplasmy as low as 1.5% being easily detected. Rapid, reproducible, and accurate results prove solid-phase minisequencing to be the method of choice for quantitative analysis of LHON mutations.
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| 67. |
- Kaukonen, M, et al.
(författare)
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A missense variant in IFT122 associated with a canine model of retinitis pigmentosa
- 2021
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Ingår i: Human genetics. - : Springer Science and Business Media LLC. - 1432-1203 .- 0340-6717. ; 140:11, s. 1569-1579
-
Tidskriftsartikel (refereegranskat)abstract
- Retinitis pigmentosa (RP) is a blinding eye disease affecting nearly two million people worldwide. Dogs are affected with a similar illness termed progressive retinal atrophy (PRA). Lapponian herders (LHs) are affected with several types of inherited retinal dystrophies, and variants in PRCD and BEST1 genes have been associated with generalized PRA and canine multifocal retinopathy 3 (cmr3), respectively. However, all retinal dystrophy cases in LHs are not explained by these variants, indicating additional genetic causes of disease in the breed. We collected DNA samples from 10 PRA affected LHs, with known PRCD and BEST1 variants excluded, and 34 unaffected LHs. A genome-wide association study identified a locus on CFA20 (praw = 2.4 × 10–7, pBonf = 0.035), and subsequent whole-genome sequencing of an affected LH revealed a missense variant, c.3176G>A, in the intraflagellar transport 122 (IFT122) gene. The variant was also found in Finnish Lapphunds, in which its clinical relevancy needs to be studied further. The variant interrupts a highly conserved residue, p.(R1059H), in IFT122 and likely impairs its function. Variants in IFT122 have not been associated with retinal degeneration in mammals, but the loss of ift122 in zebrafish larvae impaired opsin transport and resulted in progressive photoreceptor degeneration. Our study establishes a new spontaneous dog model to study the role of IFT122 in RP biology, while the affected breed will benefit from a genetic test for a recessive condition.
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| 68. |
- Kedra, D, et al.
(författare)
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Characterization of the human synaptogyrin gene family.
- 1998
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Ingår i: Human Genetics. - : Springer Science and Business Media LLC. - 0340-6717 .- 1432-1203. ; 103:2, s. 131-41
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Tidskriftsartikel (refereegranskat)abstract
- Genomic sequencing was combined with searches of databases for identification of active genes on human chromosome 22. A cosmid from 22q13, located in the telomeric vicinity of the PDGFB (platelet-derived growth factor B-chain) gene, was fully sequenced. Using an expressed sequence tag-based approach we characterized human (SYNGR1) and mouse (Syngr1) orthologs of the previously cloned rat synaptogyrin gene (RATSYNGR1). The human SYNGR1 gene reveals three (SYNGR1a, SYNGR1b, SYNGR1c) alternative transcript forms of 4.5, 1.3 and 0.9 kb, respectively. The transcription of SYNGR1 starts from two different promoters, and leads to predicted proteins with different N- and C-terminal ends. The most abundant SYNGR1 a transcript, the 4.5-kb form, which corresponds to RATSYNGR1, is highly expressed in neurons of the central nervous system and at much lower levels in other tissues, as determined by in situ hybridization histochemistry. The levels of SYNGR1b and SYNGR1c transcripts are low and limited to heart, skeletal muscle, ovary and fetal liver. We also characterized two additional members of this novel synaptogyrin gene family in human (SYNGR2 and SYNGR3), and one in mouse (Syngr2). The human SYNGR2 gene transcript of 1.6 kb is expressed at high levels in all tissues, except brain. The 2.2-kb SYNGR3 transcript was detected in brain and placenta only. The human SYNGR2 and SYNGR3 genes were mapped by fluorescence in situ hybridization to 17qtel and 16ptel, respectively. The human SYNGR2 gene has a processed pseudogene localized in 15q11. All predicted synaptogyrin proteins contain four strongly conserved transmembrane domains, which is consistent with the M-shaped topology. The C-terminal polypeptide ends are variable in length, display a low degree of sequence similarity between family members, and are therefore likely to convey the functional specificity of each protein.
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| 69. |
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| 70. |
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