Muscle MRI as a Diagnostic Challenge in Emery-Dreifuss Muscular Dystrophy.

Emery-Dreifuss Muscular Dystrophy (EDMD) is an early-onset, slowly-progressive group of myopathies, presenting with joint contractures, muscle weakness and cardiac abnormalities. Variants in the EMD gene cause an X-linked recessive form (EDMD1). The scarce EDMD1 muscle MRI accounts in the literature describe fatty replacement of posterior thigh and leg muscles.We report a 22-year-old patient with early-onset bilateral joint contractures, slowly progressive muscle weakness and minor cardiac rhythm abnormalities. A novel loss-of-function variant of EMD was identified and deemed probably pathogenic in the absence of emerin detection by immunofluorescence and Western Blot. MRI revealed fatty replacement of the lumbar spinal erectors and the posterior compartment of lower limbs. Interestingly, Short Tau Inversion Recovery (STIR) sequences showed a heterogenous hyper signal on the vasti, hamstrings and left lateral gastrocnemius muscles.Oedema-like abnormalities were previously reported in early stages of other muscular dystrophies, preceding fatty replacement and muscle atrophy, but not in EDMD1 patients. We hypothesize that these oedema-like changes may be a marker of early muscle pathology in EDMD1. Further studies focusing on these abnormalities in the early phase of EDMD1 are required to test our hypothesis.