Duchenne muscular dystrophy is caused by a defective gene for
dystrophin (a protein in the muscles). However, it often occurs
in people without a known family history of the condition.
Because of the way the disease is inherited, boys are affected,
not girls. The sons of females who are carriers of the disease
(women with a defective gene but no symptoms themselves) each
have a 50% chance of having the disease. The daughters each have
a 50% chance of being carriers. Duchenne muscular dystrophy
occurs in about 1 out of every 3,600 male infants. Because this
is an inherited disorder, risks include a family history of
Duchenne muscular dystrophy. Symptoms usually appear before age
6 and may appear as early as infancy. They may include: Duchenne
muscular dystrophy leads to quickly worsening disability. Death
usually occurs by age 25, typically from lung disorders.
Congestive heart failure (rare) Heart arrhythmias (rare) Mental
impairment (varies, usually minimal) Permanent, progressive
disability Decreased abilit