IRX1 was associated with slower increase in TVW over time [−0.06 mm/year, 95% CI: (0.01–0.10), P = 0.016] and KCNIP1 with faster increase in TVW (+0.05 mm/year, 95% CI: 0.01–0.10, P = 0.022) in whole group analysis but neither were replicated in the MS-only subgroup. Here, KCNIP1 is linked to myeloid sarcoma.