Sequence variation in the transforming growth factor-beta1 (TGFB1) gene and multiple sclerosis susceptibility

Genome screenings in multiple sclerosis (MS) have identified multiple susceptibility regions supporting a polygenic model for this disease. Evidence for linkage was consistently observed at ch.19q13 suggesting the presence of an MS gene(s) in this region. Several interesting candidate genes are encoded within this region, including transforming growth factor-beta 1 (TGFB1) and interleukin-11 (IL11). Both are multifunctional cytokines with significant and well-characterized immunomodulatory properties. We performed a comprehensive evaluation of common polymorphisms within the TGFB1 and IL11 loci and three closely flanking microsatellite markers (D19S421, CEA, D19S908) in 161 stringently ascertained and clinically characterized MS multiplex families using tests of both linkage (lod score, sib-pair analysis) and association (pedigree disequilibrium test or PDT). Patients and families were stratified by HLA-DR2 status to search for two-locus interactions. Suggestive evidence for linkage and association to CEA (lod score = 1.25, theta = 0.20, p = 0.015, respectively), located 0.4 cM from TGFB1, was observed in DR2 positive families only. Distinct clinical phenotypes were also examined and an association between a TGFB1 haplotype and a mild disease course was present (p = 0.008), raising the possibility that TGFB1 or a nearby locus may influence disease expression.