Classification of Myopathies: By Pathologic Features

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• Neurogenic myopathies

• Inflammatory myopathies

• Defects on neuromuscular transmission

• Developmental disorders

• Defects of extracellular matrix and sarcolemma

• Myonuclear envelopathies

• Defects associated with ion channel and ion transport

• Abnormal myofibrillar and internal cytoskeletal proteins

• Abnormal metabolism

• Intoxication and poisoning

• Iatrogenic disorders

• Endocrine disorders

• Associated with abnormal trinucleotide repeats

• Associated with large deletions

• Muscle disorders associated with cancer

• Miscellaneous myopathies

Neurogenic myopathies Head

• Denervation

• Disuse atrophy

Inflammatory myopathies Head

• Not associated with known infectious agents

• Inclusion body myositis

• Polymyositis

• Dermatomyositis

• Associated with infectious agents

• Virus myositis

• Bacterial myositis

• Fungal infection

• Parasites

• Trichinosis

• Cysticerosis

• Toxoplasmosis

• Sarcosporidiosis

• Microsporidiosis

Defects on neuromuscular transmission Head

• Congenital myasthenic syndromes

• Myasthenia gravis

• The Lambert-Eaton myasthenic syndrome

Developmental disorders Head

• Myotubular myopathy, X-linked type

• Centronuclear myopathies

• Congenital fiber type disproportion

Defects of extracellular matrix and sarcolemma Head

• Dystrophinopathies (Duchenne and Becker muscular dystrophy)

• Collagen VI gene mutations (Limb girdle dystrophies, type 1B, aka Bethlem myopathy)

• Caveolinopathies (Limb girdle dystrophies, type 1C)

• Dysferlinopathies (Limb girdle dystrophies, type 2B)

• Sarcoglycanopathies (Limb girdle dystrophies, type 2C, 2D, 2E, and 2F)

• Merosin (Lamin alpha-2) gene mutation (Congenital muscular dystrophy, merosin deficient type)

• Heparin sulfate proteoglycan (perlecan) deficiency (Schwartz-Jampel syndrome)

• Alpha-7 integrin deficiency associated muscular dystrophy

Myonuclear envelopathies Head

• Emerinopathy (X-linked Emery-Dreifuss muscular dystrophy)

• Lamins A/C mutations (Autosomal dominant Emery-Dreifuss muscular dystrophy)

Defects associated with ion channel and ion transport Head

• Myotonia and paramyotonia

• Dyskalemic episodic weakness

• Malignant hyperthermia (Ca⁺⁺ channels of the sarcotubular system)

• Central core disease (Ca⁺⁺ channels of the sarcotubular system)

• Brody disease (defects on Ca⁺⁺ pump)

Abnormal myofibrillar and internal cytoskeletal proteins Head

• Actinpathies

• Core diseases (Central core disease, multicore disease)

• Desmin-related myopathies (desminopathies)

• Nemaline myopathies

• Plectin deficiency

• Telethonin deficiency

• Myotilinopathy

• Myosin heavy chain depletion syndrome

• Autosomal dominant myosin heavy chain IIa myopathy

Abnormal metabolism Head

• Lysosomal disorders

• Alpha-glucosidase deficiency (Type II glycogenosis)

• LAMP-2 deficiency

• X-linked myopathy with excessive autophagy

• Defects of non-lysosomal proteolysis

• Calpain 3 deficiency

• Carbohydrate storage

• Alpha-glucosidase deficiency (Type II glycogenosis)

• Amyloglucosidase (Type III glycogenosis)

• Myophosphorylase (Type V glycogenosis)

• Phosphofructose kinase (Type VII glycogenosis)

• Amylo-trans-glucosidase (Type IV glycogenosis)

• Phosphoglycerate kinase (Type IX and X glycogenosis)

• Defects of oxidative fatty-acid metabolism (defects of b-oxidation)

• Defects of oxidative phosphorylation (mitochondrial disease)

• Miscellaneous

• Myoadenylate deaminase deficiency

Intoxication and poisoning Head

Iatrogenic disorders Head

• Steroid myopathy

• Cochicine myopathy

• Others

Endocrine disorders Head

Associated with abnormal trinucleotide repeats Head

• Myotonic dystrophy (adult type, congenital type)

• PABPN1 dysfunction in oculopharyngeal muscular dystrophy

Associated with large deletions Head  

• Type 2 muscle fiber atrophy (Facioscapulohumeral Dystrophy)

Muscle disorders associated with cancer Head

• Type 2 muscle fiber atrophy

• Dermatomyositis

• Paraneoplastic necrotizing myopathy

• Amyloid myopathy

• Scleromyxedema

• Myopathy with anti-Decorin antibodies

Miscellaneous myopathies Head

• Hereditary inclusion body myopathies

• Reducing body myopathy

• Hyaline body myopathy

• Marinesco-Sjögren syndrome

• Vitamin E deficiency

• Osteomalacia myopathy

• Others