Myofibrillar Myopathy with Limb-Girdle Phenotype in a Thai Patient
Teerin Liewluck MD*, Jutatip Kintarak MD**, Tumtip Sangruchi MD*, Duygu Selcen MD***, Kongkiat Kulkantrakorn MD****
Affiliation : * Department of Pathology and Neurogenetics Network, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand ** Department of Pathology, Faculty of Medicine, Thammasat University, Pathumthani, Thailand *** Department of Neurology and Neuromuscular Research Laboratory, Mayo Clinic, Rochester, Minnesota, USA **** Division of Neurology, Department of Internal Medicine, Faculty of Medicine, Thammasat University, Pathumthani, Thailand
Myofibrillar myopathy (MFM) encompasses a genetically and clinically heterogeneous group of inherited or sporadic skeletal muscle disorders characterized pathologically by the presence of myofibrillar dissolution associated with accumulation of myofibrillar degradation products and ectopic expression of multiple proteins especially Z-disk related proteins. Patients with MFM initially present with muscle weakness and commonly developed cardiomypathy in the advanced stage. To date, mutations of genes encoding Z-disk proteins or proteins maintaining myofibrillar integrity including ZASP, MYOT, DES, FLNC and CRYAB underlie MFM. The authors herein report a 29-year-old Thai woman with a clinical diagnosis of autosomal dominant limb-girdle muscular dystrophy (LGMD1) who has one affected grandmother. The patient was subsequently found to have MFM based on her myopathological findings. Analyses of all MFM-genes known to date revealed no mutations. The current case emphasizes the importance of muscle biopsy in LGMD1 patients and a wide range of phenotypic variations among patients with MFM. The causative genes underlying the majority of MFM remain uncovered. Close monitoring of the cardiac function is crucial to prevent mortality among these patients.
Keywords : αB-crystallin, Desmin, Filamin C, Limb-girdle muscular dystrophy, LGMD, Myofibrillar myopathy, Myotilin, ZASP
