TAP2 GENE POLYMORPHISM CONTRIBUTES TO GENETIC SUSCEPTIBILITY TO MULTIPLE-SCLEROSIS

MS is an autoimmune demyelinating disease that has been known to be as sociated with the HLA-DRB11501-DQA1*0102-DQB1*0602 haplotype. TAP1 an d TAP2, two genes encoded within the MHC class II region between HLA-D P and -DQ loci, display genetic variability and are involved in the tr ansport of antigenic peptides from the cytoplasm to the endoplasmic re ticulum. Comparison of 116 MS patients with Caucasoid controls did not reveal any significant correlation between the previously described a lleles of the TAP1 and TAP2 genes and MS. We report: here an additiona l TAP2 dimorphism at codon 386, called I and J, corresponding to a sil ent mutation. An increased frequency of the J variant was observed in the patient population. The J mutation was not found in linkage disequ ilibrium with the HLA-DRB11501 allele and can be considered an addist ional genetic susceptibility marker of the disease.