Titre :
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Congenital myasthenic syndrome with episodic apnea in a female infant caused by two diferent compound heterozygous mutations of the CHAT-gene (abstract : congrès international de Myologie, 2005)
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contenu dans :
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Auteurs :
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Congrès international de myologie 2005 (International Congress of Myology 2005; 9-13 mai 2005; Nantes, France) ;
Sasso A ;
Paucic-Kirincic E ;
Lah-Tomulic K ;
Gazdik M
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Type de document :
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Article
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Année de publication :
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2005
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Pages :
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p. 252
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Langues:
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Anglais
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Mots-clés :
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apnée
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biopsie musculaire
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cerveau
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chromosome 10
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colloque
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électromyographie
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étude de cas
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faiblesse musculaire
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gène CHAT
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jonction neuromusculaire
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mort subite
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muscle squelettique
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mutation génétique
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pharmacothérapie
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ptosis
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pyridostigmine
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syndrome myasthénique congénital
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Résumé :
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Communication n° 18 Congenital myasthenic syndrome with episodic apnea (CMS-EA) is a presynaptic disorder of neuromuscular junction. CMS-EA manifests at birth or early infancy. The clinical signs of the disease are ptosis, intermittent hypotonia and sudden respiratory insufficiency or apnea. In conditions such as infections, fever or overexertion there is a great risk of sudden death or anoxic brain damage. The cause of CMS-EA is recently identified mutation in the CHAT gene. Muscle biopsy in CMS-EA is normal. Prolonged stimulation of muscle bundles at 10 Hz results in abnormal decrease of amplitude of the miniature end plate potentials. Nine months old female infant was admitted in hospital because of sudden apnea during bath. At that time she was febrile 37, 8 C and she had a respiratory infection. Clinical examination showed mild bilateral ptosis and mild generalized muscle weakness. Electromyography after 10 Hz stimulation for 5 minutes showed a decremental response. Pyridostigmin was included in therapy. She was followed during 2 years and showed normal development. In our patient CHAT gene on chromosome 10q11.2 encoding the presynaptic protein Choline O-acetyltransferase was analysed. By direct sequencing of the coding regions two compound heterozygous mutations of the CHAT-gene were identified: the mutation S694C in exon 18 ( tct>tgt) and the mutation T354M in exon 10 ( acg>atg). Both mutations are missense mutations leading to an amino acid exchange. The mutation S694 C has been described in a CMS family recently . The mutation T354M has not been described before. The mother is heterozygous carrier of the mutation S694C, and the father is heterozygous carrier of the mutation T354M. The asymptomatic brother does not carry any of the mutation.
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