LAUSR

We thank Dr de Fuenmayor-Fernández de la Hoz and colleagues for their interest in our paper and their comments. Clearly distinguishing neurogenic from myogenic disease processes is not always straightforward and we fully share the view that, to some extent, myopathic alterations on muscle biopsy may come along with long-standing denervation, thus configuring a so-called "secondary myopathy". This could in fact be the major contributing factor to explain the imaging and pathology features of patient 4 in our paper. However, we disagree that muscle biopsy findings in patient 1 resemble the picture reported in their patient.