Journal of Rheumatic Diseases

Table. 1.

Differential diagnoses of dysferlinopathy

Characteristic Dysferlinopathy Dermatomyositis Polymyositis Inclusion body myositis Immune-mediated necrotizing myopathy

LGMD2B Miyoshi myopathy
Age of onset 17∼25 years Children and adults Adults >50 years Patients treated with statins (increased risk with advanced age >80 years)
Sex preference Not found Female>male Female>male Male>female Female>male
Onset & course Usually slowly progressive; Occasionally subacute presentation (25%) Subacute progressive weakness Acute or subacute progressive weakness Insidious onset, slowly progressive Acute or subacute progressive weakness
Muscle weakness Predominantly pelvic and shoulder girdle muscle weakness, distal involvement may present Most marked only in distal and posterior parts of the legs, initial muscle atrophy of gastrocnemius and soleus Proximal>distal Proximal>distal Distal and proximal; usually asymmetric finger flexor and proximal leg weakness Proximal>distal
Dysphagia No Yes Yes Yes Yes
Dermatologic involvement No Yes No No Rare
CK Elevated (more than 10 to 70-fold, often >100-fold) Normal or elevated (up to 50-fold) Elevated (often >10-fold, up to 50-fold) Normal or elevated (<10-fold) Elevated (often >10-fold)
EMG Myopathic Myopathic Myopathic Myopathic Myopathic
MRI Fat suppressed T2 and STIR weighted sequences may demonstrate hyperintensities (muscle edema), difficult to differentiate from inflammatory myopathies. Dysferlinopathy shows diffuse muscle edema and fatty degeneration, while inflammatory myopathies show predominant patchy muscle edema and mild fatty degeneration
Pathology Inflammatory features in 40% or more cases, similar to those of DM, Dystrophic muscle pattern and variable morphologic findings related to duration of symptoms; Absence or partial deficiency of dysferlin by immunoblot. Plasma membrane microlesions and subsarcolemmal vesical accumulation on electron microscopy Perifascicular, perimysial or perivascular inflammatory cell infiltrate; CD4+ T cell and B cell dominant, perifascicular atrophy, MAC deposition within necrotic fibers Endomysial, perimysial, perivascular inflammatory cell infiltrate, non-necrotic fibers invaded by predominantly CD8+ T cell, CD8/MHC-1 complex, MAC deposition within necrotic fibers Endomysial inflammatory cell infiltrate; rimmed vacuoles and eosinophilic inclusions Muscle-cell necrosis and regeneration, macrophage infiltrates in endomysial and perivascular regions, relative absence of lymphocyte infiltration, MHC-1 complex and MAC deposition
Response to immunosuppressive therapy Poor Good Good Generally poor Good

LGMD 2B: Limb-Girdle Muscular Dystrophy type 2B, CK: creatine kinase, EMG: electromyography, MAC: membrane attack complex, MRI: magnetic resonance imaging, STIR: short-tau inversion recovery, MHC: major histocompatibility complex, DM: dermatomyositis.

J Rheum Dis 2021;28:101~106 https://doi.org/10.4078/jrd.2021.28.2.101
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