C T1-weighted MRI axial images at thigh and calf levels show that the fatty degeneration is more prominent in thigh muscles, equally affecting posterior and anterior compartment, with relative sparing of the rectus femoris, sartorius and gracilismuscles until late stages (4, 10 and 11, respectively). Strikingly, the fatty tissue is located in the internal parts of almost all the affected muscles in thigh (1, 2, 3, 5-9), while the external regions are spared. At calf level, only the gastrocnemius medialis muscle (12) shows this pattern, while the soleus (13) is diffusely involved. Patient II.2 (PII.2) shows late-stage thigh muscles with an unusual involvement of the tibialis posteriormuscle (14) in the lower leg. 