Lack of replication of KIF1B gene in an Italian primary progressive multiple sclerosis cohort

Background: KIF1B gene represents the first non-inflammatory gene with a putative role on axonal loss and neurodegeneration found to be associated with multiple sclerosis (MS). The objective of this study is to test the association of the rs10492972 C allelic variant of KIF1B gene in a large Italian cohort of patients with primary progressive and progressive relapsing MS (PPMS and PRMS), which represents a subtype of MS mainly driven by neurodegenerative phenomena. Methods: rs10492972 has been genotyped in an outbred sample of 222 primary PPMS and PRMS and 221 healthy controls of unique northern Italian origin using the TaqMan assay. Results: A non-significant age- and sex-adjusted odds ratio of 0.96 [95% confidence interval (CI) 0.71-1.31] has been found in C carriers, and a non-significant risk of 0.99 [95% CI 0.77-1.63] in C carriers according to a dominant model. Stratification by sex, age at onset younger than 35 years and symptoms at the onset of the disease did not reveal any significant findings. No influence on disability progression, measured with the multiple sclerosis severity score, was found in C carriers. Conclusions: These results suggest that there is no effect in carrying the rs10492972 C variant on the risk of disease as well as on the rate of disability progression in a cohort of Italian patients with PPMS and patients with PRMS. These data need to be confirmed in an independent sample of patients with progressive MS.