Inclusion Criteria:  Control population without inflammatory myopathy (population 1), suspected myopathy for whom a blood test and muscle biopsy are required to confirm the diagnosis Confirmed inflammatory myopathy (population 2) Control population without systemic sclerosis (population 3), with primary Raynaud's phenomenon Early diffuse systemic cutaneous scleroderma (population 4) Male or female (age ≥ 18, no upper age limit)  Exclusion Criteria:  Populations 1 & 2  Contraindication to muscle biopsy Diagnosed for another neuromuscular disease Taking an immunosuppressant / immunomodulator treatment within 3 months before inclusion Unbalanced cardiovascular pathology  Population 3 & 4  Contraindication to skin biopsy Capillaroscopic and / or immunological anomaly suggesting scleroderma Suspicion of scleroderma but diagnosed for another connectivitis Immunosuppressive treatment (corticosteroids> 15 mg, methotrexate, mycophenolate mofetil) introduced for more than 1 month Active or recent cancer <3 years (apart from non-melanoma skin cancer).  For all  - Pregnancy or breast feeding