Muscular
dystrophy is a rare inherited muscle disease in which the muscle fibers are
unusually susceptible to damage. The muscles, primarily the voluntary muscles,
become progressively weaker. In the late stages of muscular dystrophy, muscle
fibers often are replaced by fat and connective tissue. There are several
types of muscular dystrophy. The various types of the disease affect more than
50,000 Americans. Many are associated with specific genetic abnormalities.
The most common muscular dystrophies appear to be due to a genetic deficiency of
the muscle protein dystrophin. These types of the disease are called
dystrophinopathies. They include:
Duchenne's muscular dystrophy . This is the most severe form of
dystrophinopathy. Duchenne's muscular dystrophy affects young boys. Signs
and symptoms of the disease usually appear between the ages of 2 and 5. Children
with the disease fall and have difficulty getting up off the floor. By late
childhood most are unable to walk. Most die by their late teens or early 20s,
often from pneumonia, respiratory muscle weakness or cardiac complications.
Becker's muscular dystrophy . This is a milder form of dystrophinopathy.
It generally affects older boys and young men, and progresses more slowly,
usually over several decades. Duchenne's and Becker's muscular dystrophy
are passed from mother to son through one of the mother's genes. Women who have
the defective gene that causes these muscular dystrophies are simply carriers
and exhibit no signs or symptoms of the disease. The disease can skip a
generation until another son inherits the defective gene. In some cases of
Duchenne's and Becker's muscular dystrophies, the disease arises from a new
mutation in a gene rather than from an inherited defective gene. There are
many other less common types of muscular dystrophy characterized by different
patterns of muscle weakness. Some are passed along in the same inheritance
pattern that marks Duchenne's and Becker's muscular dystrophies. Other types of
muscular dystrophies can be handed on from generation to generation and affect
males and females equally. Still others require a defective gene from both
parents.
(from the Mayo Clinic website)
Dave
Krueger DKrue49431@aol.com
Return to Genealogy and Medicine
Return to The Tuley Family Roots & Branches Page