Faculty Bibliography

Multiple sclerosis (MS) is a neurological, demyelinating disorder with a putative autoimmune etiology. It is thought to be a multifactorial disease with a complex mode of inheritance. Here we report the results of a two-stage genomewide scan for loci predisposing to MS. The first stage of the screen, with a low-resolution map, was performed in a selection of 16 pedigrees collected from an isolated Finnish population. Multipoint, non-parametric linkage analysis of the 328 markers did not reveal statistically significant results. However, 10 slightly interesting regions (P = .1-.15) emerged, including our previous findings of the HLA complex on 6p21 and a putative locus on 5p14-p12. Eight of these novel regions were further analyzed by use of denser marker maps, in the second stage of the scan. For the chromosomal regions 4cen, 11tel, and 17q, the statistical significance increased, but not conclusively; for 2q32 and 10q21, the statistical significance did not change. Accordingly, genotyping of the high-density markers in these regions was performed, and the data were analyzed by use of two-point, parametric linkage analysis using the complete pedigree information of the 21 Finnish multiplex families. We detected suggestive evidence for a predisposing locus on chromosomal region 17q22-q24. Several markers on 17q22-q24 yielded positive LOD scores, with the maximum LOD score (Zmax) occurring with D17S807 (Zmax = 2.8, theta = .04; dominant model). Interestingly, a suggestive linkage between MS and the markers on 17q22-q24 was also revealed by a recent genomewide scan in MS families from the United Kingdom.

The role of genetic factors in the etiology of multiple sclerosis (MS) has been clearly demonstrated but the loci determining susceptibility to this disease remain largely unidentified. A contribution from several immune system genes has been suggested based on animal models and association/linkage analyses on MS patients and families. With the exception of the findings from the HLA complex, studies on candidate immune system genes have provided controversial results. Here we have performed genetic association and linkage analyses on four chromosomal regions containing immune system genes. A possible role for each of these loci in MS has been previously suggested. In data-sets derived from the Finnish population we found no evidence for contribution of the T-cell receptor beta chain (TCR beta chromosome 7q35), immunoglobulin heavy chain (IGH chromosome 14q32), interferon-gamma (IFN-gamma chromosome 12q14-q15) or interleukin-1 receptor antagonist/interleukin-1 beta (IL-1ra/IL-1 beta chromosome 2q14-q21) loci in the genetic susceptibility to MS.

Multiple sclerosis (MS) is a chronic inflammatory disorder characterized by multifocal damage of myelin in the central nervous system (CNS). The prevalence of this putative autoimmune disease is 0.1% in individuals of northern European origin. Family, adoption and twin studies implicate genetic factors in the aetiology. MS is widely speculated to be a multifactorial disorder with a complex mode of inheritance. Despite many studies of candidate genes, only an association with HLA-DR2-DQ6 has been generally detected, and the number of susceptibility genes remains unknown. The chronic variant of experimental allergic encephalomyelitis (EAE), a T-cell mediated autoimmune disease in rodents, represents a relevant animal model for MS given the chronic relapsing disease course and inflammatory changes of CNS observed in these demyelinating disorders. Susceptibility to EAE is also influenced by the major histocompatibility complex (MHC). Human syntenic regions to murine loci predisposing to EAE were tested as candidate regions for genetic susceptibility of MS. Three chromosomal regions (1p22-q23, 5p14-p12 and Xq13.2-q22) were screened in 21 Finnish multiplex MS families most originating from a high risk region in western Finland. Several markers yielded positive lod scores on 5p14-p12, syntenic to the murine locus Eae2. Our data provide evidence for a predisposing locus for MS on 5p14-p12.