Bethlem myopathy 1B

A Bethlem myopathy that has_material_basis_in heterozygous, compound heterozygous, or homozygous mutation in the COL6A2 gene on chromosome 21q22.

Signs and symptoms

• Centrally nucleated skeletal muscle fibers
• Muscle fiber splitting
• Elevated circulating creatine kinase activity
• Increased endomysial connective tissue
• Abnormality of skeletal muscle fiber size
• Proximal muscle weakness
• Muscle fiber necrosis
• Elbow contracture
• Distal muscle weakness
• Interphalangeal joint contracture of finger