Examination revealed both proximal and distal

muscle weakness in 17 patients, of whom 10 presented with more proximal weakness, five with more distal weakness and two with equal proximal and distal weakness. There were only two patients with isolated proximal weakness and one patient with isolated distal weakness. There were eight patients with muscle atrophy, one patient with bilateral gynaecomastia and one patient with spine ankylosis. All 25 living Selleck SCH772984 patients were examined by electrocardiogram and echocardiography at the time of diagnosis. Twenty-four patients (24/25, 96%) presented with miscellaneous cardiac arrhythmia, including 15 patients (15/24, 60%) with complete atrial ventricular block, five patients small molecule library screening (5/24, 20.8%) with complete right or left bundle branch block, four patients (4/24, 16.7%) with premature ventricular beats, two patients (2/24, 8.3%) with atrial fibrillation, one patient (1/24, 4.2%) with a junctional escape beat and one patient (1/24, 4.2%) with supraventricular tachycardia. However, only six patients had abnormalities of cardiac function and morphology on examination by echocardiography,

including dilated cardiomyopathy in one patient, hypertrophic cardiomyopathy in one patient, restrictive cardiomyopathy in two patients, and atrium dilation in two patients. The serum creatine kinase level Glycogen branching enzyme was normal in five patients, elevated to 280–1760 IU/l in 12 patients, and not determined in eight patients. Electromyograms were performed in nine patients. Myogenic patterns were recorded in eight patients, and myogenic with neurogenic changes in one patient.

In five cases (index cases of family 1, family 4, family 5, one affected individual of family 4 and sporadic case 2), muscle pathology showed a dystrophy-like pattern with great variation in fibre diameters ranging from 10 to 160 µm, significant internal nuclei, an increase in split fibres, and significant connective tissue proliferation in the perimysium. Necrotic fibres and regenerating fibres were uncommon. COX-negative fibres were observed in two cases. Sparse endomysial inflammatory cells appeared in three cases. Four other patients (one affected individual of family 1, index cases of family 2 and 3, as well as sporadic case 1) exhibited a myopathy-like pattern with fibre diameters ranging from 20 to 90 µm, a few internal nuclei, and no connective tissue proliferation (Table 2 and Supporting Information). The abnormal structures were best observed by MGT staining in the affected fibres (Figure 1A,B). The abnormal fibres contained one or more of the following features: (i) Abnormal areas with blue amorphous materials.