Canalopathy

The canalopathies are the whole of the diseases in connection with a dysfunction of the ionic channels membrane.
This new term appeared thanks to considerable progress making it possible to connect old clinical demonstrations with anomalies of the structure of proteins by change of the Gène responsible for their coding

Introduction

The ionic channels are proteins which cross the cellular membrane and which control in a selective way the passage of the ions through this one. The ionic channels control the cellular electric activity and are thus implied in each beat of the heart, each muscular contraction and even in each thought and perception.
Their operations involve electric movements of charges through the cellular membrane and modify the polarity of this one:
  • Depolarization by entry of positive ion (current known as entering )
  • Repolarization or hyperpolarisation by exit of positive ion or entry of negative ion (current known as outgoing )
More than 20 genetic diseases are in connection with a dysfunction of ionic channels appearing by cardiac disorders of the rythmicity and muscular contraction, but also some epilepsy S, neurodégénératives diseases…

History

Until 1982 the study of the physiological bases of the electric activity cellular was based on physical models, in particular the study of the striated muscles with the batrachians. The cloning of the sub-unit alpha of the receiver of the Acétylcholine was a major stage of comprehension and discovery of the whole of genes coding the operation of the membrane ionic channels.
In 1998, the discovery of the crystalline structure of the bacterial potassic channels made it possible to include/understand various deteriorations being able to lead to faulty operations.
The number very significant of genetic diseases related to disorders of operation of the ionic channels with conduit to create the term of canalopathy to indicate the whole of these diseases.

Genes coding the operation of the ionic channels

Various canalopathies

Canalopathies in connection with a disorder of the operation of the sodic channels

Muscular

The muscular canalopathies are in connection with the change of gene SCN4A located on the locus q23.1-q25.3 of the Chromosome 17

Cardiac

The cardiac canalopathies are in connection with the change of gene SCN5A located on the locus p21 of the Chromosome 3

Cerebral

The cerebral canalopathies are in connection with several changes
  • the change of the genes SCN1A, SCN2A located on the locus q24 and q23-q24.3 of the Chromosome 2
  • the change of gene SCN1B located on the locus p21 of the Chromosome 3

Nervous

The cardiac canalopathies are in connection with the change of gene SCN9A located on the Chromosome 2

Canalopathies in connection with a disorder of the operation of the calcic channels

Canalopathies in connection with a disorder of the operation of the potassic channels

Canalopathies in connection with a disorder of the operation of the chloric channels

Sources

  • The channelopathies: Novell insights into molecular and genetic mechanisms off human disease Robert S. Kass J. Covering joint. Invest. 115:1986 - 1989 (2005). DOI: 10.1172/JCI26011

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