An investigation of the C77G and C772T variations within the human protein tyrosine phosphatase receptor type C gene for association with multiple sclerosis in an Australian population.

Multiple sclerosis (MS) is a common cause of neurological disability in young adults. The disease generally manifests in early to middle adulthood and causes various neurological deficits. Autoreactive T lymphocytes and their associated antigens have long been presumed important features of MS pathogenesis. The Protein tyrosine phosphatase receptor type C gene (PTPRC) encodes the T-cell receptor CD45. Variations within PTPRC have been previously associated with diseases of autoimmune origin such as type 1 diabetes mellitus and Graves' disease. We set out to investigate two variants within the PTPRC gene, C77G and C772T in subjects with MS and matched healthy controls to determine whether significant differences exist in these markers in an Australian population. We employed high resolution melt analysis (HRM) and restriction length polymorphism (RFLP) techniques to determine genotypic and allelic frequencies. Our study found no significant difference between frequencies for PTPRC C77G by either genotype (Chi(2)=0.65, P=0.72) or allele (Chi(2)=0.48, P=0.49). Similarly, we did not find evidence to suggest an association between PTPRC C772T by genotype (Chi(2)=1.06, P=0.59) or allele (Chi(2)=0.20, P=0.66). Linkage disequilibrium (LD) analysis showed strong linkage disequilibrium between the two tested markers (D'=0.9970, SD=0.0385). This study reveals no evidence to suggest that these markers are associated with MS in the tested Australian Caucasian population. Although the PTPRC gene has a significant role in regulating CD4+ and CD8+ autoreactive T-cells, interferon-beta responsiveness, and potentially other important processes, our study does not support a role for the two tested variants of this gene in MS susceptibility in the Australian population.