Our previous studies showed the association of multiple sclerosis with the same marker haplotype encompassing the CCL3 gene in two independent sets of families. Here we present that sequencing of this haplotype and its flanking regions detected no new mutation, but 16 single nucleotide polymorphisms (SNP) and 1 insertion/deletion variant in both affected and unaffected individuals. Transmission distortion analyses of the newly identified variants in the second set of families revealed no individual marker association. In the absence of a single disease relevant variant within the MS associated haplotype and the surrounding linkage disequilibrium block, the highlighted haplotype may itself indicate a functionally relevant allelic combination or interaction.