Abstract:

OBJECTIVE: To characterize the clinical course of myopathy associated with antibodies to signal recognition particle (SRP), or anti-SRP myopathy.
DESIGN: Case series.
SETTING: Keio University Hospitals and National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan.
PATIENTS: We reviewed clinical features of 27 patients with anti-SRP myopathy and analyzed disease progression and neurological outcome.
MAIN OUTCOME MEASURES: Anti-SRP antibodies in serum were detected by RNA immunoprecipitation assay using extracts of K562 cells.
RESULTS: Of the 27 patients, 5 (19%) showed chronic progressive muscle weakness as well as atrophy of limbs and trunk muscles from a younger age with more severe neurological outcomes compared with the other 22 patients(81%) with the subacute form.
CONCLUSION: A subset of patients with anti-SRP myopathy can show a chronic progressive form associated with severe clinical deficits.

日本語要旨:

抗SRP陽性ミオパチーは急性の強い筋力低下、血清CK値の著高、ステロイド不応性の自己免疫性筋疾患である。我々は本邦抗SRP抗体ミオパチー27例について、その臨床経過を詳細に解析した。その結果、18,5%は筋ジストロフィーと鑑別困難な慢性の経過をとり、筋萎縮も進行性で予後不良であった。抗SRP抗体ミオパチーの臨床経過はきわめて多彩であることを明らかにした。