Abundant kif21b, defined as expression above the median, was associated with a two-fold accelerated development of the Kurtzke Expanded Disability Status Scale (EDSS) 6.0 (median time in low kif21b group 16 years vs. high kif21b 7.5 years, log-rank test p = 0.04) in MS.
We have shown significant reductions in KIF5A, KIF21B and KIF1B messenger ribonucleic acid (mRNA) expression and also KIF5A protein expression in MS grey matter, as compared to control grey matter.
KIF21B polymorphisms were found associated with susceptibility to multiple sclerosis and ankylosing spondylitis (AS) in populations of white European ancestry.
As SNPs in KIF21B increase risk for both inflammatory bowel disease and multiple sclerosis, this suggests a common pathway in the pathogenesis of these diseases.