Inclusion Criteria:  • both sexes  with permanent myalgia, spontaneous or on effort, with or without muscle deficit, with or without HyperCkemia without known etiologies Age from 6 to 80 years consulting for the first time or followed at CERCA giving their free and informed consent to participate after information on the research Affiliated to the social security system  Exclusion Criteria:  Person placed under guardianship and/or curatorship Myalgias related to a known etiology