Pendant le Congrès Myologie 2005,
le Pr Fontaine a présenté le mercredi 11 mai 2005, lors du
symposium parallèle "Canalopathies" une communication dont le titre est : "Les
maladies musculaires liées aux canaux ioniques".
> Texte de sa communication en anglais
:
MUSCULAR ION CHANNEL DISORDERS
Ion channels are integral transmembrane
proteins that regulate inner and outer flows of ions through the muscle
membrane, as well as generate and propagate action potentials. The proper
functioning of the muscle membrane relies on a balanced muscle membrane
excitability. Mutations in genes encoding ion channels modify this subtle
equilibrium driving the membrane towards states of either hyper- or
hypo-excitability. Mechanism linking abnormal channel functioning to membrane
excitability are well understood for chloride and sodium channel mutations. They
remain however mysterious for some of the sodium and calcium channel mutations.
Modifications in the state of excitability of the muscle membrane are the basis
of symptoms in patients i.e. stiffness (myotonia) or weakness (paralysis). The
better understanding of the pathophysiology of symptoms enables a more rationale
therapeutic choice. Progess have been made in the diagnosis of these diseases.
Exercise tests coupled to electromyography are sensitive enough to detect
abnormal muscle membrane excitability and to predict groups of mutations.
Molecular diagnosis can also be obtained on a routine basis. Clinical and
paraclinical investigations of these rare disorders have improved through a
national collaborative network: Resocanaux.