(A, B) 1.5 T MR inversion recovery images from a patient with fragile X mental retardation (FMR1) gene premutation and a diagnosis of multiple sclerosis, as described in case No 1. (A) Axial image shows abnormal high signal intensity, predominately in subependymal and deep white matter. (B) Axial image shows normal signal intensity in the middle cerebellar peduncles. (C, D) MRIs of a female with fragile X associated tremor/ataxia syndrome (case not described in this report). (C) Axial flair image shows relatively sparse periventricular white matter changes. (D) Axial flair image shows increased signal intensity in the middle cerebellar peduncles.