Multiple sclerosis (MS) is conceptualised as a complex autoimmune inflammatory disorder in which several environmental factors act together in a genetically susceptible individual to cause disease. Epidemiological data confirmed that genetic factors are involved in MS pathogenesis. Genes responsible for MS predisposition still await to be identified. The only consistent genetic finding, establishes so far, is the association between MS and a number of HLA haplotypes (locus 6p21.3). NFKBIL1 gene (locus 6p21.31) is one of candidate genes. One of NFKBIL1 gene coding sequence polymorphisms is a non-synonymous thymine-cytosine substitution at position 738 (exon 4) resulting in cysteine-arginine substitution at position 224 of encoded protein.
The aim of the study: To assess the NFKBIL 1 exon 4 contribution to MS genetic predisposition and its relationship to the clinical course of the disease.
Material and methods: 107 unrelated MS patients (77 female ones) attended in Department of Neurology Medical University of Poznari participated in this study. Control group included 110 healthy age and sex matched unrelated volunteers (71 female). Investigation of NFKBIL1 exon 4 polymorphism was performed with use of the single strand conformation polymorphism technique (SSCP).
Results: NFKBIL1 exon 4 polymorphism was observed in 10 patients and 9 control samples (9.35% and 8.18% respectively). The results remained statistically insignificant (p = 0.8136). Associations between the polymorphism and course of MS, clinical symptoms at onset, sex (p = 0.2851) and optic neuritis (ON) (p = 0.0865) were also insignificant. However, lack of statistical significance in the two latter parameters suggests insufficient size of the patients and control groups, as the absolute percentage values were remarkably different (respectively: 7.59% female vs. 14.28% male; 2.5% ON-positive vs. 13.4% ON-negative).
Conclusions: The results of the present study do not provide evidence for the association between the NFKBIL1 exon 4 polymorphism and MS predisposition in the investigated Polish population. However, it may have a restricted result on MS course and a protecting effect on optic neuritis in MS patients.