Myofibrillar myopathy

**Definition:** Myofibrillar myopathies are a heterogeneous group of disorders, characterised by the pathologic finding of myofibrillar disruption on electron microscope with a spectrum of histological abnormalities including excessive desmin accumulation in muscle fibres.

**Exclusions:** - Myasthenia gravis or certain specified neuromuscular junction disorders - Secondary myopathies