Affiliations: [a] Friedrich-Baur-Institute, Department of Neurology, Ludwig-Maximilians-University of Munich, Munich, Germany
| [b] Department of Chemical Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| [c] Department of Radiology, Ludwig-Maximilians-University of Munich, Munich, Germany
| [d] National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| [e] Muscle Disease Unit, Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
Correspondence:
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Correspondence to: Maggie C. Walter, MD, MA., Friedrich-Baur-Institute, Department of Neurology, Ludwig-Maximilians-University of Munich, Ziemssenstrasse 1, 80336 Munich, Germany. Tel.: +49 89 4400 57400; Fax: +49 89 4400 57402; E-mail: maggie.walter@lrz.uni-muenchen.de.
Abstract: Background:Anti-3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR)-myopathy is a usually rapidly progressive form of immune-mediated necrotizing myopathy (IMNM). Rarer clinical courses show slow progression and resemble the phenotype of limb-girdle dystrophy (LGMD). Objective:We demonstrate the difficulties in differentiating LGMD versus anti-HMGCR-myopathy. Methods:We report on a 48-year-old patient with slowly progressive tetraparesis and hyperCKemia for more than 20 years. Results:Due to myopathic changes in initial and second muscle biopsy and typical clinical presentation, the patient was diagnosed with LGMD 20 years ago; despite comprehensive genetic testing including exome diagnostics, the genetic cause of disease could not be identified. Finally, HMG-CoA reductase antibodies were detected, confirming the diagnosis of anti-HMGCR-myopathy. By re-work-up of a second muscle biopsy specimen from year 2009, the diagnosis of a IMNM was made in retrospect. Seven cycles of high-dose immunoglobulins were administered; patient reported outcome measures have mildly improved. Conclusion:Patients with clinical LGMD phenotype, degenerative changes in muscle biopsy but without genetic confirmation of the disease should be tested for HMG-CoA-myopathy, thereby allowing for an early start of treatment.
