CX3CR1 and multiple sclerosis: In multiple sclerosis patients, CX3CR1-Val249Ile polymorphisms have revealed that the Cx3cr1 Ile249 Thr280 haplotype could have a protective effect by impairing the switch of multiple sclerosis from the relapsing–remitting type into the secondary progressive type [61,62], and patients with the variant in both alleles (homozygosity) have a higher risk for disability.