Muscle MRI in McArdle Disease: A European Multicenter Observational Study.

The primary findings are that patients with GSDV exhibit severe fat-replacement of the paraspinal muscles, which can have important implications for the future management of patients with GSDV, and also significant fat-replacement of shoulder-girdle muscles as previously described. The clinical relevance of the discrete increases in lower limb FF is uncertain. The changes were found to be age-related in both groups, but an accelerated effect was found in GSDV, probably due to continuous muscle damage.