Clinical and Radiological Features of Korean Patients With Anti-HMGCR Myopathy
Eun Kyoung Oh, Seung‐Ah Lee, Hyun Joon Lee, Yoon Jin, Sung Jun Kim, Hyung-Soo Lee, Bum Chun Suh, Ha Young Shin, Seung Woo Kim, Byeol‐A Yoon, Seong‐il Oh, Yoo Hwan Kim, Joong‐Yang Cho, Jeong Hee Cho, Ki-Han Kwon, Young‐Chul Choi, Hyung Jun Park
Abstract
Background and PurposeTo understand the characteristics of Korean patients with anti-3-hydroxy-3-methylglutaryl-coenxyme A reductase (HMGCR) myopathy, we measured anti-HMGCR antibodies and analyzed the clinical, radiological, and pathological features of patients with anti-HMGCR myopathy. MethodsWe measured titers of anti-HMGCR antibodies in the sera of 99 patients with inflammatory myopathy, 36 patients with genetic myopathy, and 63 healthy subjects using an enzyme-linked immunosorbent assay.We tested 16 myositis-specific autoantibodies (MSAs) in all patients with anti-HMGCR myopathy.Results Positivity for the anti-HMGCR antibody was observed in 17 (4 males and 13 females) of 99 patients with inflammatory myopathy.The median age at symptom onset was 60 years.Ten (59%) of the patients with anti-HMGCR positivity had taken statins.The titer of anti-HMGCR antibodies was significantly higher in the statin-nave group (median=230 U/mL, interquartile range=170-443 U/mL) than in the statin-exposed group (median=178 U/mL, interquartile range=105-210 U/mL, p=0.045).The most common symptom was proximal muscle weakness in 15 patients (88%), followed by myalgia in 9 (53%), neck weakness in 4 (24%), dysphagia in 3 (18%), and skin lesions in 2 (12%).The median titer of anti-HMGCR antibody was 202 U/mL.We found eight different MSAs in nine (53%) patients.The median disease duration from symptom onset to diagnosis was significantly shorter in the MSA-positive group than in the MSA-negative group (p=0.027). ConclusionsOur study was the first to measure anti-HMGCR antibodies in inflammatory myopathy.It has provided new findings, including the suggestion of the coexistence of other MSAs in Korean patients.