Value of muscle magnetic resonance imaging in the differential diagnosis of muscular dystrophies related to the dystrophin-glycoprotein complex

Zhiying Xie,Yilin Liu,Jiangxi Xiao,Yun Yuan,Wei Zhang,Zhihao Xie,Ying Zhu,Meng Yu,Chengyue Sun,Chen Ling,Yiming Zheng,Zhaoxia Wang

doi:10.1186/s13023-019-1242-y

Abstract

BackgroundDystrophin-glycoprotein complex (DGC)-related muscular dystrophies may present similar clinical and pathological features as well as undetectable mutations thus being sometimes difficult to distinguish. We investigated the value of muscle magnetic resonance imaging (MRI) in the differential diagnosis of DGC-related muscular dystrophies and reported the largest series of Chinese patients with sarcoglycanopathies studied by muscle MRI.ResultsFifty-five patients with DGC-related muscular dystrophies, including 22 with confirmed sarcoglycanopathies, 11 with limb-girdle muscular dystrophy 2I (LGMD2I, FKRP-associated dystroglycanopathy), and 22 with dystrophinopathies underwent extensive clinical evaluation, muscle biopsies, genetic analysis, and muscle MRI examinations. Hierarchical clustering of patients according to the clinical characteristics showed that patients did not cluster according to the genotypes. No statistically significant differences were observed between sarcoglycanopathies and LGMD2I in terms of thigh muscle involvement. The concentric fatty infiltration pattern was observed not only in different sarcoglycanopathies (14/22) but also in LGMD2I (9/11). The trefoil with single fruit sign was observed in most patients with dystrophinopathies (21/22), and a few patients with sarcoglycanopathies (4/22) or LGMD2I (2/11). Hierarchical clustering showed that most patients with sarcoglycanopathies or LGMD2I can be distinguished from dystrophinopathies based on the concentric fatty infiltration pattern and trefoil with single fruit sign at the thigh level on muscle MRI.ConclusionsMuscle MRI at the thigh level potentially allows distinction of sarcoglycanopathies or FKRP-associated dystroglycanopathy from dystrophinopathies.

Highlights

Dystrophin-glycoprotein complex (DGC)-related muscular dystrophies may present similar clinical and pathological features as well as undetectable mutations being sometimes difficult to distinguish
DGC-related muscular dystrophies include dystrophinopathies caused by mutations in Duchenne muscular dystrophy (DMD), sarcoglycanopathies caused by mutations in SGCG, SGCA, SGCB, and SGCD, and dystroglycanopathies caused by mutations in FKRP and other genes associated with the O-mannose glycosylation pathway of α-DG [1,2,3]
Clinical phenotypes of patients with sarcoglycanopathies, LGMD2I or dystrophinopathies ranged from hyperCKemia or mildly affected to severe patients who had lost independent ambulation

Summary

Introduction

Dystrophin-glycoprotein complex (DGC)-related muscular dystrophies may present similar clinical and pathological features as well as undetectable mutations being sometimes difficult to distinguish. Mutations in genes encoding DGC components can trigger sarcolemma instability and eventually lead to the development of muscular dystrophies [1]. DGC-related muscular dystrophies include dystrophinopathies caused by mutations in DMD, sarcoglycanopathies caused by mutations in SGCG, SGCA, SGCB, and SGCD, and dystroglycanopathies caused by mutations in FKRP and other genes associated with the O-mannose glycosylation pathway of α-DG [1,2,3]. Differential diagnosis among different DGCrelated muscular dystrophies cannot be made on clinical characteristics alone. Confirmatory diagnosis of DGC-related muscular dystrophies relies mainly on genetic testing. It is necessary to establish other tests that can support differential diagnosis among different DGC-related muscular dystrophies

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Conclusion