More than 250 different forms of human neuromuscular
diseases are known. They differ in age of onset, severity
of weakness, rate of progression, type of inheritance,
groups of muscles affected, frequency of incidence.
Sometimes the clinical symptoms are not restricted to
nervous and/or muscular tissue. The muscular dystrophies
form an extensive subdivision of the neuromuscular
diseases. This group of disorders is inheritable and it
is accompanied by progressive weakness and degeneration
of skeletal muscle. The aetiology is not known. The most
progressive type of the dystrophies is the Duchenne form,
first described in detail by Duchenne de Boulogne in
1868 (83) . Another representative, with several
dissimilarities with the Duchenne type, is the myotonic
dystrophy, also called dystrophia myotonica, myotonia
atrophica or Steinert•s disease. This disorder shows,
apart from dystrophic characteristics, myotonic symptoms,
i.e. there exists a delay in relaxation of the affected
muscles after contraction. The myotonic and Duchenne types
are the most frequently occurring forms of human muscular
dystrophy. These types of muscular dystrophy have been the
subject of this thesis, and details of the disorders will
be given first