| 1. |
- Enerbäck, Charlotta, 1965, et al.
(author)
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Cytogenetic analysis of 477 psoriatics revealed an increased frequency of aberrations involving chromosome region 11q
- 1999
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In: Eur J Hum Genet. ; 7:3, s. 339-44
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Journal article (peer-reviewed)abstract
- Psoriasis is an inflammatory skin disorder affecting approximately 3% of the population. Genetic studies published so far have shown a complex genetic inheritance with heterogeneity and a putative major susceptibility locus in the HLA region on chromosome 6. We have collected a large amount of material consisting mostly of small nuclear families in order to perform a genome-wide scan for psoriasis-associated genes. In order to focus the scan properly on possible candidate regions, we performed a cytogenetic analysis of 477 unrelated psoriatics. We divided our findings into sporadic, affecting a minor fraction of the cells, and constitutional, i.e. they were present in all cells examined. We found three cases of balanced translocation, all of which involved chromosome 11q. Two of these had a breakpoint in q12-13, whilst one involved the telomeric part of chromosome 11q. In order to characterise further the breakpoint on 11q12-13, we used bacterial artificial chromosomes (BACs) analysed by fluorescent in situ hybridisation (FISH). We were able to show that the persons had a close, but not identical breakpoints; they were separated by at least 5 cM. The major atopy locus is located in this region, as well as a locus for insulin-dependent diabetes mellitus, both being conditions with a pathogenetic mechanism involving antigen presentation.
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| 2. |
- Enerbäck, Charlotta, 1965, et al.
(author)
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Evidence that HLA-Cw6 determines early onset of psoriasis, obtained using sequence-specific primers (PCR-SSP)
- 1997
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In: Acta Derm Venereol. ; 77:4, s. 273-6
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Journal article (peer-reviewed)abstract
- Psoriasis vulgaris has previously been shown to associate with certain HLA alleles. HLA-Cw6 is considered to be the primary association, based on calculations of relative risk after serological typing. This association is reportedly more pronounced in early- than in late-onset psoriasis. We performed a PCR-based typing with sequence-specific primers, which has been shown to give a more complete result than serology. Two hundred and one unrelated patients with psoriasis, with a mean age of 40 years, and 77 healthy controls were typed. Two thirds (67%) of the patients were positive for one or two copies of the allele, while the corresponding figure for the control group was 12%. A significant peak for age at onset of 21 or younger was seen for the Cw6 carriers. For patients older than 21 at onset, the frequency of Cw6 was significantly lower; e.g. for patients with an age at onset between 30 and 35 the frequency was comparable to the level of the control group. The high frequency of Cw6 among patients with an age at onset of 21 or younger is in agreement with data of other groups. In comparison with this age-at-onset group the frequency of Cw6 is sharply reduced among patients with an age at onset of 22 years or older, which contrasts with earlier studies. This may reflect differences between population groups but may also be due to the higher sensitivity of the PCR-based HLA-Cw6 typing method. In view of these findings, we suggest that psoriasis is a genetically determined disease, in which the additional presence of HLA-Cw6 is associated with the characteristic of early onset.
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| 3. |
- Enerbäck, Charlotta, 1965, et al.
(author)
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S gene (Corneodesmosin) diversity and its relationship to psoriasis; high content of cSNP in the HLA-linked S gene
- 2000
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In: J Invest Dermatol. - 0022-202X .- 0022-202X. ; 114:6, s. 1158-63
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Journal article (peer-reviewed)abstract
- Psoriasis is a heterogeneous disease in which several reports suggest the presence of a susceptibility gene in or in the proximity of the human leukocyte antigen complex in chromosome 6p. There is an association between HLA-Cw6 and young onset of the disease. The S gene (corneodesmosin), located 160 kb telomeric of HLA-C, is a strong candidate for psoriasis due to its reportedly exclusive expression in differentiating keratinocytes. We have studied this gene in a large Swedish psoriasis population and we report a strikingly high degree of polymorphism in the coding parts of the gene, 1 every 100 base pairs. We used a stratified approach to compare the polymorphic variants in patients and controls. A single nucleotide polymorphism in the coding region leading to an amino acid exchange (Ser-->Phe) that differed significantly between patients and controls was identified (position 619). Owing to a high allele frequency in a larger control group, however, and an insignificant influence of the variant on the age at onset distribution curve based on a large psoriasis population, we could not confirm that this coding single nucleotide polymorphism was involved in disease etiology. We also examined the single nucleotide polymorphism in position 1243, recently proposed to have an influence on the pathogenesis of the disease. This polymorphism showed less association to the disease as compared with the single nucleotide polymorphism at positions 619 and 722. Such a high degree of variation present also in an HLA gene which is not involved in immune response indicates the difficulty involved in assessing the role of a specific allele in the pathogenesis of a complex disease in this region. A strong association effect due to linkage disequilibrium in an extended region in the HLA complex is also a complicating factor.
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| 4. |
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| 5. |
- Enerbäck, Charlotta, 1965, et al.
(author)
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Stronger association with HLA-Cw6 than with corneodesmosin (S-gene) polymorphisms in Swedish psoriasis patients.
- 2000
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In: Archives of dermatological research. - : Springer Science and Business Media LLC. - 0340-3696 .- 1432-069X. ; 292:11, s. 525-30
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Journal article (peer-reviewed)abstract
- Psoriasis vulgaris is strongly associated with certain human leukocyte antigens, especially in early onset. The purpose of this study was to study the HLA-Cw6 allele and its contribution to disease susceptibility in a set of 104 families with at least two affected siblings. A sequencing method was utilized to examine the two exons that build up the antigen binding site of the C locus receptor. DNA from patients homozygous for Cw6 based on haplotype information were sequenced. The results confirmed the identity of the Cw6 allele in affected individuals with the consensus sequence for Cw*0602. We screened the set of families for psoriasis patients homozygous for Cw6 and found 11 individuals with a mean age at onset of 16.1 years. The corresponding figure for the Cw6 heterozygotes was 18.45 years and for the Cw6-negatives 22.36 years. This is indicative of a gene dose effect. We performed a transmission disequilibrium test (TDT) on the Cw6 allele per se, used as a biallelic marker. The analysis resulted in a P-value of 5.3 x 10(-17) (t167/nt45). This greatly exceeds our previous results of a TDT in the region, including microsatellite markers and single nucleotide polymorphisms (SNPs) in the coding part of the S gene (corneodesmosin), which is a suggested candidate gene in the region. The maximum nonparametric linkage (NPL) value was also reached using HLA-C as a marker. We conclude that Cw6 is the allele which shows the highest degree of association with psoriasis in our set of families and we propose that it directly influences the age at onset of the disease rather than increasing the genetic load in accordance with a polygenic theory.
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| 6. |
- Enlund, Fredrik, 1968, et al.
(author)
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Analysis of three suggested psoriasis susceptibility loci in a large Swedish set of families: confirmation of linkage to chromosome 6p (HLA region), and to 17q, but not to 4q
- 1999
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In: Hum Hered. ; 49:1, s. 2-8
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Journal article (peer-reviewed)abstract
- Psoriasis is known to be a heterogeneous disease with so far three reported major psoriasis susceptibility loci on chromosome 4q, 6p and 17q. In this study we investigated three reported gene locations by nonparametric and parametric linkage analysis in a large family set consisting of 104 families (153 sib pairs) from Sweden. We could confirm linkage to chromosome 6p. A maximum heterogeneous lod score of 2.78 was reached at locus D6S276 (alpha = 0.60). Allelic association studies within the HLA region indicated linkage disequilibrium at locus TNFbeta with a significant p value of 0.0009. Furthermore, we obtained weak evidence of linkage to the locus on chromosome 17q while no evidence of linkage could be found to the chromosome 4q region.
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| 7. |
- Enlund, Fredrik, 1968, et al.
(author)
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Psoriasis susceptibility locus in chromosome region 3q21 identified in patients from southwest Sweden
- 1999
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In: Eur J Hum Genet. ; 7:7, s. 783-90
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Journal article (peer-reviewed)abstract
- We have performed a pair-wise linkage study in the search for psoriasis susceptibility regions. A preliminary scan was performed on 20 families. In this set we obtained indications of linkage on chromosome 3q21. This region was further investigated using material from a total of 104 families (set 1B) resulting in a non-parametric linkage (NPL) of 1.77. The material was stratified in families whose parental origin is in southwest Sweden (set 1C). A maximum NPL value of 2.77 was obtained in this group. A transmission disequilibrium test (TDT) was performed on the stratified material (set 1C) and a significant P value of 0.005 was obtained, at marker D3S1269. The locus was confirmed with TDT in replicate material consisting of 148 families in which a single member was affected (P value 0.0007) at marker D3S1551. Thus, we have observed a significant P value using TDT in the vicinity of markers D3S1269/D3S1551, suggesting a novel psoriasis susceptibility region.
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| 8. |
- Hewett, D., et al.
(author)
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Identification of a psoriasis susceptibility candidate gene by linkage disequilibrium mapping with a localized single nucleotide polymorphism map
- 2002
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In: Genomics. - : Elsevier BV. - 0888-7543 .- 0888-7543. ; 79:3, s. 305-14
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Journal article (peer-reviewed)abstract
- Psoriasis is a chronic inflammatory disease of the skin with both genetic and environmental risk factors. Here we describe the creation of a single-nucleotide polymorphism (SNP) map spanning 900-1200 kb of chromosome 3q21, which had been previously recognized as containing a psoriasis susceptibility locus, PSORS5. We genotyped 644 individuals, from 195 Swedish psoriatic families, for 19 polymorphisms. Linkage disequilibrium (LD) between marker and disease was assessed using the transmission/disequilibrium test (TDT). In the TDT analysis, alleles of three of these SNPs showed significant association with disease (P<0.05). A 160-kb interval encompassing these three SNPs was sequenced, and a coding sequence consisting of 13 exons was identified. The predicted protein shares 30-40% homology with the family of cation/chloride cotransporters. A five-marker haplotype spanning the 3' half of this gene is associated with psoriasis to a P value of 3.8<10(-5). We have called this gene SLC12A8, coding for a member of the solute carrier family 12 proteins. It belongs to a class of genes that were previously unrecognized as playing a role in psoriasis pathogenesis.
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| 9. |
- Samuelsson, Lena, 1962, et al.
(author)
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A genome-wide search for genes predisposing to familial psoriasis by using a stratification approach
- 1999
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In: Hum Genet. - 0340-6717 .- 0340-6717. ; 105:6, s. 523-9
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Journal article (peer-reviewed)abstract
- We have performed a genome scan, using markers spaced by 10 cM, in the search for psoriasis-susceptibility loci. The family material of 134 affected sibling pairs was ascertained on the basis of a population genetic study in which 65% of the probands had two healthy parents. Genotyping results were analyzed for non-random excessive allele-sharing between sib pairs by using GENEHUNTER ver 1.1. A stratification approach was applied to increase the homogeneity of the material by means of an operational definition of joint complaints among affected individuals. Significant linkage to the human leukocyte antigen region on chromosome 6p in a cohort including 42 families without joint complaints (nonparametric linkage score of 2.83, P=0.002) strongly supported the validity of this operational definition as it replicated results from an earlier linkage report with similar stratification criteria. New candidate regions on chromosomes 3 and 15 were identified. The highest non-parametric linkage values in this study, 2.96 (P=0.0017) and 2.89 (P=0.0020), were reached on chromosome 15 in a subgroup with joint complaints and on chromosome 3 in a subgroup without joint complaints. In addition, confirmation of previously reported loci was established on chromosomes 4q, 6p, and 17q. This study indicates that distinct disease loci might be involved in psoriasis etiology for various phenotypes.
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| 10. |
- Swanbeck, Gunnar, 1934, et al.
(author)
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A population genetic study of psoriasis
- 1994
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In: Br J Dermatol. - 0007-0963. ; 131:1, s. 32-9
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Journal article (peer-reviewed)abstract
- We present epidemiological data for 5197 families with psoriasis. Errors in reporting have been analysed. Analysis of the data provides indications of random mating with respect to whether the partner has the skin disease or not. Data on psoriasis among parents, siblings and children are provided, and particular attention has been paid to the age at onset of psoriasis. Psoriasis was present in the parents of about 36% of the probands. In families in which one or both parents have psoriasis, the occurrence of the disease among the siblings does not provide any information which differentiates between a dominant and recessive mode of inheritance, but is compatible with both. In families in which neither parent had psoriasis, provided there was a proband with psoriasis, the probability of the siblings suffering from psoriasis was close to 0.25, indicating a recessive mode of inheritance. The distribution of psoriasis among the parents of all probands, and among the children of probands, was also compatible with this mode of inheritance. The prevalence of psoriasis in the elderly was estimated to be about 5%, and the gene frequency in the whole population 25%. These findings show that, with regard to first-degree relatives, the inheritance of psoriasis can fit an autosomal recessive model. The concept of a recessive mode of inheritance may be used as a basis for genetic counselling.
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