Myotonic Dystrophy   Myotonic dystrophy is an inherited disorder
that affects muscle tone, and hair loss and can involve varying
degrees of impaired cognitive abilities. It is inherited as a
dominant disorder, which means that individuals that carry the
defective gene have the disease. The amount of symptoms
exhibited in persons with myotonic dystrophy varies.   Physical
limitations resulting from myotonic dystrophy can be
significant, involving muscle weakness and difficulty lifting
items and performing certain routine daily tasks. There are many
cases in which affected persons experience mental delays, and
this usually correlates with the extent of the genetic defect.
Myotonic dystrophy is a progressive disorder in terms of muscle
weakness and muscle wasting.   Myotonic dystrophy is relatively
rare, occurring approximately once in 8,000 people. There is
also a more rare, severe congenital form that occurs with an
incidence of about 1 in 100,000.  Causes and symptoms  Myotonic
dystrophy involves many differe