Only one previous study examined the cross-sectional relationship specifically between GFAP and DTI-based measures and showed similar findings.36 In that study, higher serum GFAP levels measured in 62 people with multiple sclerosis were significantly associated with lower NABT/NAWM FA and higher NAWM MD values.36 We corroborate their findings and further extend them with mid-term longitudinal data. The gene discussed is GFAP; the disease is multiple sclerosis.