Myotonic dystrophy type 1 (DM1) and 2 (DM2), the most common muscular problem in young adults, belong to the first group, whereas the sodium channelopathies and the chloride channelopathies or myotonia congenita belong to the second (reviewed in Morales and Cuenca 2004).
Myotonia congenita (MC) is a hereditary muscular disease, electrophysiologically characterized by presenting increased excitability of the muscular fiber, which is due to repetitive action potentials of the muscle membranes, which is reflected in clinical myotonia, muscular stiffness and hypertrophy (Meyer-Kleine et al.
The phenotype was consistent with a clinical diagnosis of myotonia congenita, Becker disease.
Inherited disorders that present myotonia as a major sign include DM1 and DM2, chloride channelopathies or myotonia congenita (Thomsen and Becker diseases) and sodium channelopathies (paramyotonia congenita, potassium-aggravated myotonia and hyperkalemic periodic paralysis) (reviewed in Morales and Cuenca 2004).
What are myotonia congenita and paramyotonia congenita?
Two other forms of myotonia congenita appear to be caused by a defective gene on chromosome 7.
What is the difference between myotonia congenita and paramyotonia congenita?