MRI demonstrated fatty infiltration of all thigh muscles, in particular the adductor magnus, which was almost completely replaced by fat, with relative sparing of the vastus lateralis, rectus femoris, gracilis, and semitendinosus, a pattern of selective involvement previously associated with RYR1-related myopathies.14,15 There was no family history of similar symptoms. This evidence concerns the gene RYR1 and myopathy.