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Biomedical subjects

Eva Akesson

Publications and source records attributed to Eva Akesson.

6 recordsLinked to original sources

MHC2TA is associated with differential MHC molecule expression and susceptibility to rheumatoid arthritis, multiple sclerosis and myocardial infarction.

Antigen presentation to T cells by MHC molecules is essential for adaptive immune responses. To determine the exact position of a gene affecting expression of MHC molecules, we finely mapped a previously defined rat quantitative trait locus regulating MHC class II on microglia in an advanced intercross line. We identified a small interval including the gene MHC class II transactivator (Mhc2ta) and, using a map over six inbred strains combined with gene sequencing and expression analysis, two conserved Mhc2ta haplotypes segregating with MHC class II levels. In humans, a -168A --> G polymorphism in the type III promoter of the MHC class II transactivator (MHC2TA) was associated with increased susceptibility to rheumatoid arthritis, multiple sclerosis and myocardial infarction, as well as lower expression of MHC2TA after stimulation of leukocytes with interferon-gamma. We conclude that polymorphisms in Mhc2ta and MHC2TA result in differential MHC molecule expression and are associated with susceptibility to common complex diseases with inflammatory components.

Animals↗

Concordance for disease course and age of onset in Scandinavian multiple sclerosis coaffected sib pairs.

BACKGROUND: Investigation of coaffected sib pairs is one method to determine the genetic influence on the clinical presentation of many complex diseases, such as multiple sclerosis (MS). Investigation of the clinical concordance in coaffected sib pairs may be a prerequisite to identify genes that modify the clinical outcome. The aim of this study was to investigate a possible genetic influence on selected demographic and clinical variables among familial Scandinavian MS cases. MATERIAL AND METHODS: We identified 136 Caucasian Scandinavian families with MS coaffected sib pairs from Denmark, Norway and Sweden. Cohen's kappa coefficient and the intraclass correlation coefficient were used to assess concordances in sib pairs. Furthermore, clinical features and HLA-DR2 carrier status were compared among the probands of sib pairs. RESULTS: We found significant concordance of the disease course (kappa = 0.28, P < 0.001) and adjusted age of onset (r = 0.23, P = 0.028). Among probands of sib pairs, HLA-DR2 carrier patients had a younger age of onset (P = 0.024). CONCLUSION: Analyses of Scandinavian coaffected sib pairs suggest that disease course and age of onset are partly under genetic control. Furthermore, HLA-DR2 in probands of sib pairs suggests importance for age of onset.

Age of Onset↗

Refining the linkage analysis on chromosome 10 in 449 sib-pairs with multiple sclerosis.

Genome-wide screens for linkage in multiplex families with multiple sclerosis (MS) from United Kingdom, Sardinia, Italy and the Nordic countries (Denmark, Finland, Norway and Sweden) have each shown suggestive or potential linkage on chromosome 10. The partially overlapping regions identified by these studies encompass around 60 cM of the chromosome. In order to explore this region further, we typed 13 microsatellite markers in the same 449 families originally studied in the individual screens. This additional genotyping increased the information extraction in the region from 52% to 79% and revealed increased support for linkage (MLS 2.5) peaking at 10p15.

Alleles↗

Two genome-wide linkage disequilibrium screens in Scandinavian multiple sclerosis patients.

We report the first two genome-wide screens for linkage disequilibrium between putative multiple sclerosis (MS) susceptibility genes and genetic markers performed in the genetically homogenous Scandinavian population, using 6000 microsatellite markers and DNA pools of approximately 200 MS cases and 200 controls in each screen. Usable data were achieved from the same 3331 markers in both screens. Nine markers from eight genomic regions (1p33, 3q13, 6p21, 6q14, 7p22, 9p21, 9q21 and Xq22) were identified as potentially associated with MS in both screens.

Alleles↗

A whole genome screen for linkage disequilibrium in multiple sclerosis confirms disease associations with regions previously linked to susceptibility.

Linkage analysis in multiplex families has provisionally identified several genomic regions where genes influencing susceptibility to multiple sclerosis are likely to be located. It is anticipated that association mapping will provide a higher degree of resolution, but this more powerful approach is limited by the substantial genotyping effort required. Here, we describe the first use of DNA pooling to screen the whole genome for association in multiple sclerosis based on a 0.5 cM map of microsatellite markers and using four DNA pools derived from cases (n = 216), controls (n = 219) and trio families (n = 745 affected individuals and their 1490 parents). The 10 markers showing the greatest evidence for association with multiple sclerosis that emerge from this analysis include three from the HLA region on chromosome 6p (D6S1615, D6S2444 and TNFa), providing a positive control for the method, four from regions previously identified by linkage analysis in UK multiplex families (two mapping to chromosome 17q GCT6E11 and D17S1535; one to chromosome 1p GGAA30B06; and one to 19q D19S585), and three from novel sites with respect to linkage analysis (D1S1590 at 1q; D2S2739 at 2p; and D4S416 at 4q). Our results thus provide further supporting evidence for the candidature of 6p, 17q, 19q and 1p as regions encoding susceptibililty genes for multiple sclerosis. The protocol used in this UK-based study is now being extended to 18 additional sites in Europe in order to search for susceptibility genes shared between populations of common ancestry, as well as those that exert ethnically more restricted effects.

Adult↗