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Neurogenetics
Published in John W. Scadding, Nicholas A. Losseff, Clinical Neurology, 2011
Sonia Gandhi, Sarah Tabrizi, Nicholas Wood
The congenital myopathies are a group of rare diseases characterized by congenital floppiness, muscle weakness and skeletal dysmorphism. The diagnosis is usually based on the morphological abnormalities found on muscle biopsy. Two forms are described here. Central core disease (CCD) is an autosomal dominant condition, with features of central amorphous areas within the muscle fibre. It is caused by mutations in the ryanodine receptor and is allelic to one form of malignant hyperthermia susceptibility. Patients with CCD are at risk of malignant hyperthermia. Nemaline myopathy (NM) is a condition characterized on biopsy by rod-shaped structures in the muscle fibres. It may be autosomal dominant or autosomal recessive and has three forms: severe congenital, typical congenital and adult onset. The genes that underlie this condition encode sarcomeric thin filament proteins: mutations in a and b tropomyosin genes cause autosomal dominant NM; mutations in nebulin, troponin-I, NEM1 and NEM2 cause autosomal recessive NM. Mutations in a actin have been reported with both autosomal dominant and recessive NM.
Real food in enteral nutrition for chronically ill children: overview and practical clinical cases
Published in Current Medical Research and Opinion, 2022
Valeria Dipasquale, Antonella Diamanti, Chiara Maria Trovato, Domenica Elia, Claudio Romano
A 22-month-old girl was diagnosed with nemaline myopathy, which is caused by a homozygous missense truncating mutation in TNNT1. Her older sister had the same mutation and disease, and both parents had a single mutation of the gene. Progressive and severe muscle weakness and wasting, respiratory insufficiency, pectus carinatum deformities, and failure to thrive manifested by the age of four months. For these reasons, she was admitted to the hospital at the age of 19 months and given a tracheostomy and a percutaneous endoscopic gastrostomy (PEG). She began to be ventilated mechanically 24 h a day. She was also started on a special diet consisting of blended natural food via PEG and nocturnal enteral nutrition consisting of 240 ml of a semi-elemental formula delivered at a rate of 30 ml/h for 8 h. No complications (i.e. gastrostomy tube obstruction, microbial contamination episodes) were observed with the use of blended natural food. The semi-elemental formula was not tolerated; thus, an amino acid-based formula was chosen instead.
Ophthalmological Manifestations of Hereditary Myopathies
Published in Journal of Binocular Vision and Ocular Motility, 2022
Marta Saint-Gerons, Miguel Angel Rubio, Gemma Aznar, Ana Matheu
Nemaline myopathy (NM) represents the most common entity within the group of congenital myopathies.5 NM is characterized by the presence of rod-like structures in the cytoplasm of muscle fibers.12 NM is caused mainly by recessive mutations of NEB (encoding nebulin), dominant mutations of ACTA1 (encoding skeletal alpha-actin), and less frequently by mutations of other genes.5 There are five clinical forms of nemaline myopathy ranging from the severe neonatal form, which occurs at birth with severe hypotonia to the variant of onset in adults that has a milder phenotype. Nemaline rods can be seen infrequently in other neuromuscular disorders, such as dermatomyositis and HIV myopathy.10 In most cases, there are no ophthalmic manifestations; however, isolated cases have been described.13,14