What telomeres teach us about MS

•Leukocyte telomere length (LTL) is well recognized as a somatic marker for biological aging processes, and may provide insight into the mechanisms that drive MS progression.•Shorter leukocyte telomere length (LTL) is associated with disability progression in MS and explains 15% of the effect of chronological age on MS disability level.•Excessive telomere attrition leads to the DNA damage response and downstream senescence pathways that could contribute to MS phenotype.•While LTL is a marker of somatic aging, reproductive aging may also contribute to MS phenotype; declines in plasma anti-Müllerian hormone (AMH) level are associated with disability progression and gray matter atrophy in women with MS.