Eda Balkan and Nuray Bilge
Background: People with Multiple Sclerosis (MS) show varying responses to the same drugs, suggesting a genetic factor. In addition, certain ABCB1 gene polymorphisms have been associated with resistance to many drugs. In the era of individualized treatment, identifying possible genetic causes of drug non responsiveness in MS patients may enable the prediction of nonresponse before treatment. Research is needed to determine relationships between ABCB1 polymorphisms and patients’ clinical parameters and drug response in MS.
Objective: This study investigated the presence of ABCB1 C3435T polymorphism among patients with MS and evaluated possible associations between C3435T variants and disease activity and clinical parameters in MS.
Materials and Methods: The study included 100 patients aged 18 and over who were definitively diagnosed with MS according to the 2010 McDonald diagnostic criteria and were receiving immunomodulatory therapy, as well as a group of 100 healthy individuals. Clinical and demographic characteristics of the MS group were recorded. All study participants underwent ABCB1 C3435T genotyping. A blood sample was collected from each participant and used for DNA isolation and single-nucleotide polymorphism analysis.
Results: There was no statistically significant difference between MS patients and the healthy subjects with regard to ABCB1 C3435T variants. Mean score on the Extended Disability Status Scale was significantly higher in MS patients with the CT variant of the ABCB1polymorphism compared to those with CC and TT variants, indicating that disability was more severe in MS patients with the CT genotype of the ABCB1 C3435T polymorphism.
Conclusion: Considering the role of P-glycoprotein in drug pharmacokinetics, the results of this study suggest a possible benefit of assessing MS patients for ABCB1 gene polymorphisms. The literature includes very little information on this topic. Although the number of patients in this study was limited, the higher level of disability in MS patients heterozygous for the ABCB1 C3435T polymorphism is a novel contribution to the literature.