myopathy with myalgia, increased serum creatine kinase, and with or without episodic rhabdomyolysis 2

A muscular disease characterized by myalgia, muscle cramps, exercise intolerance, and increased serum creatine kinase with onset between the first and fourth decades of life that has_material_basis_in heterozygous mutation in the DTNA gene on chromosome 18q12.

Signs and symptoms

• Elevated circulating creatine kinase activity
• Fatty replacement of skeletal muscle
• Centrally nucleated skeletal muscle fibers
• Myalgia
• Increased variability in muscle fiber diameter
• Exercise intolerance
• Increased endomysial connective tissue
• Myositis
• Muscle weakness
• Autistic behavior