What's in the literature?

We examine the expanded spectrum of congenital myasthenic syndromes. There is a report of the clinical and electrodiagnostic features of patients with limb-girdle predominant, treatmentresponsive N-Acetylglucosamine phosphotransferase 1 mutations and a study of phenotypic variability from mutations in muscle-specific tyrosine kinase. In myasthenia gravis, fatigue is a commonly encountered symptom, and a recent report from Norway suggested that fatigue may be associated with symptoms of autonomic disturbance. Regarding childhood neuropathy/neuronopathy, Brown- Vialetto-Van Laere syndrome is a rare disorder also known as Fazio-Londe syndrome. It causes non- length dependent motor-sensory neuropathy, gait ataxia, hearing loss, and tongue fasciculations. There is now evidence that mutations in SLC52A2 encoding for the riboflavin transporter are perhaps the most common cause; and remarkably, it is responsive to riboflavin administration. In adults with asymmetric, lower motor neuron limb weakness, motor neuronopathy is one cause, but treatable entities such as multifocal motor neuropathy need to be considered. A recent study shows that there is a low rate of intravenous immunoglobulin response when used empirically in the absence of conduction block in this setting. In the myositis category, inclusion body myositis can be difficult to confirm pathologically, and a new report recommends that a panel of immunostains that assess autophagy and protein aggregation can be very sensitive and specific. Cancer-Associated myositis was found to be more common in older age and in men and in the presence of dysphagia and lower serum creatine kinase levels. We also cover neuromuscular ultrasound and new measures for assessing carpal tunnel syndrome, findings in posterior interosseous neuropathy, and ultrasound use in distinguishing chronic inflammatory demyelinating polyneuropathy from demyelinating inherited neuropathy. The use of serum fibroblast growth factor 21 as a biomarker of mitochondrial disease is reviewed and the expanding spectrum of mitochondrial disorders into later adulthood and as a new cause of potassium channel dysfunction and periodic paralysis. Last, the topics in amyotrophic lateral sclerosis that are addressed include regional and distant disease spread, the clinical and prognostic utility of neck flexor weakness, and exercise and focalbrain lesions as risk factors.