However, for a child to have one type of myotonia congenita and some forms of nemaline myopathy, two defective genes must be inherited-one from each parents.
It is characterized by delay in the ability to relax muscles after forceful contraction (myotonia) and wasting of muscles, as well as other abnormalities.
Myotonic dystrophy (DM), also called dystrophia myotonica, myotonia atrophica, or Steinert disease, is a common form of muscular dystrophy.
Exactly how the repeat of genetic information causes myotonia, the inability to relax muscles, is not yet understood.
Myotonia: Myotonias include myotonic dystrophy, myotonia congenita, paramyotonia congenita, and neuromyotonia.
In general, myotonic dystrophy causes weakness and delayed muscle relaxation called myotonia.
It is accompanied by the inability to relax the affected muscles (myotonia).
However, many patients with myotonia do experience cramping from exercise.
Symptoms of myotonia are often worse in cold temperatures.