Regarding melatonin and its circadian rhythm controlling activity, recent studies have detected significant associations between disturbances in circadian rhythm and increased risk of developing MM46.With the intention of evaluating in more detail the possible effect of this pathway in cases of MM, we compared, from the perspective of the activity of Melatonin Receptor 1 B (Trp/Phe), the controls to MM cases divided according to ISS. Here, MTNR1B is linked to Miyoshi myopathy.