Pre‐ and postsynaptic neuromuscular junction abnormalities in musk myasthenia

• Published in: Muscle & nerve 2010-08, Vol.42 (2), p.283-288
• Main Authors: Niks, Erik H., Kuks, Jan B.M., Wokke, John H.J., Veldman, Henk, Bakker, Egbert, Verschuuren, Jan J.G.M., Plomp, Jaap J.
• Format: Article
• Language: English
• Subjects: Adult; Autoantibodies - immunology; Autoimmune diseases; Biological and medical sciences; Diseases of striated muscles. Neuromuscular diseases; Electrophysiology; Female; Fundamental and applied biological sciences. Psychology; histology; Humans; in vitro electrophysiology; Medical sciences; miniature end plate potential; Motor Endplate - immunology; Motor Endplate - physiopathology; Muscle Weakness - immunology; Muscle Weakness - physiopathology; Muscle, Skeletal - immunology; Muscle, Skeletal - physiopathology; Muscular system; MuSK, myasthenia gravis; Myasthenia Gravis - immunology; Myasthenia Gravis - physiopathology; Neurology; neuromuscular junction; Neuromuscular Junction - immunology; Neuromuscular Junction - physiopathology; Peripheral nervous system. Autonomic nervous system. Neuromuscular transmission. Ganglionic transmission. Electric organ; quantal content; Receptor Protein-Tyrosine Kinases - immunology; Receptors, Cholinergic - immunology; Vertebrates: nervous system and sense organs
• ISSN: 0148-639X; 1097-4598
• DOI: 10.1002/mus.21642

Autoantibodies to muscle‐specific kinase (MuSK) can cause myasthenia gravis (MG). The pathophysiological mechanism remains unknown. We report in vitro electrophysiological and histological studies of the neuromuscular junction in a MuSK MG patient. Low levels of presynaptic acetylcholine release and small miniature endplate potentials were found. This combination of pre‐ and postsynaptic abnormalities was supported by histology, revealing partially denervated postsynaptic areas, and some degeneration of postsynaptic folds. Results suggest that anti‐MuSK antibodies reduce the stability of muscle–nerve contact. Muscle Nerve, 2010