BACKGROUND AND PURPOSE The pathogenesis of mitochondrial disease (MD) involves the disruption of cellular energy metabolism, which results from defects in the mitochondrial respiratory chain complex (MRC). We investigated whether infants with MRC I defects showed ultrastructural changes in skeletal muscle. METHODS Twelve infants were enrolled in this study. They were initially evaluated for u...

OBJECTIVE We studied familial cases of skeletal myopathy with atrial fibrillation (Af) and atrioventricular (AV) block to compare the clinical features to other myopathies associated with cardiac abnormalities. METHODS Neurologic, cardiologic, electrophysiologic, muscle pathology, and genetic studies were performed on the patients showing muscle weakness. PATIENTS Four patients (a 63-year-o...

Inflammatory myopathies such as dermatomyositis and polymyositis are well-recognized paraneoplastic syndromes. Little is known, however, about necrotizing myopathies in association with cancer. We here describe a case of paraneoplastic necrotizing myopathy with a mild inflammatory infiltrate in a patient with adenocarcinoma. After the rapid development of a severe, disabling muscle weakness, th...

First described over 50 years ago, Rett syndrome (RTT) is a neurodevelopmental disorder caused primarily by mutations of the X-linked MECP2 gene. RTT affects predominantly females, and has a prevalence of roughly 1 in every 10,000 female births. Prior to the discovery that mutations of MECP2 are the leading cause of RTT, there were suggestions that RTT could be a mitochondrial disease. In fact,...