Reversible splenial lesions with transient reduced diffusion are observed in certain diseases and conditions, including high-altitude cerebral edema, rapid withdrawal of antiseizure medications, Kawasaki disease, X-linked Charcot–Marie–Tooth disease, myelin regulatory factor (MYRF) mutations, and encephalitis/encephalopathy (Starkey et al., 2017), which have been termed reversible splenial lesion syndrome (RESLES) and cytotoxic lesions of the corpus callosum (CLOCCs) (Blaauw and Meiners, 2020). Here, MYRF is linked to Kawasaki disease.