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Table 1 Characteristics of the 100 patients with inflammatory myopathy with anti-SRP antibody

From: Inflammatory myopathy with anti-signal recognition particle antibodies: case series of 100 patients

Findings (n)
Females/males 61/39
Age at diseases onset  
 Mean ± SD 51.3 ± 19.3
 Age ≤ 15 years 8
Antecedent infection 7
Statin-exposure 5
Duration from the disease onset to the first examination  
 ≤12 months 77
 >12 months 23
Initial symptoms  
 Arms 19
 Legs 67
 Bulbar 7
 Trunk 7
Muscle weakness  
 Legs predominantly than arms 69
 Severe limbs weakness 63
 Laterality 16
 Distal muscle dominant 3
 Neck weakness 70
 Dysphagia 41
 Facial muscle involvement 10
 Cardiac muscle involvement 2
 Decreased capacity of respiratory function 12
Muscle atrophy 66
Scapular winging 10
Decreased deep tendon reflex 51
Myalgia 34
Extramuscular symptoms  
 Fever 8
 Skin rash 6
 Arthritis 4
 Raynaud phenomenon 7
 Interstitial lung disease 13
Associated disorder  
 Cancer 5
 Rheumatic disease 9
Blood examination  
 Creatine kinase (IU/L, mean ± SD) 6161 ± 4725
 Elevated C-reactive protein 17
 Antinuclear antibody positivity 5
Electromyography  
 Spontaneous activity 41/86 (48 %)
 Low-amplitude, short-duration motor unit potentials 79/86 (92 %)
Muscle images  
 Atrophy on CT or MRI 46/79 (58 %)
 Increased signals on T2 or STIR images 49/58 (84 %)
Histological diagnosis  
 Necrotizing myopathy 84
 Sporadic inclusion body myositis 0
 Polymyositis 1
 Dermatomyositis 1
 Non-specific myositis 14
Autoantibodies  
 7S RNA of SRP 100
 54-kD protein of SRP 82
 3-hydroxyl-3-methylglutatyl-coenzyme A reductase 3
 Aminoacyl transfer RNA synthetase 0
  1. SRP, signal recognition particle; STIR, short T1 inversion recovery