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Myotonic
(Steinert's Disease)
Usual Age of Onset
Birth to adulthood
Disease Characteristics
Weakness of all muscle groups accompanied by
delayed relaxation of muscles after contraction.
Affects face, feet, hands, and neck first.
Progression is slow sometimes spanning
50 to 60 years.
Inheritance
Autosomal dominant; the disease may be inherited
through either the father or the mother.
A repeated section of DNA on either chromosome
19 or chromosome 3 causes Myotonic (Steinert's Disease).
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Duchenne
(Pseudohypertrophic)
Usual Age of Onset
2 to 6 years
Disease Characteristics
General muscle weakness and wasting,
affecting pelvis, upper arms, and upper legs first.
Duchenne progresses slowly. But eventually it
involves all voluntary muscles.
Survival is rare beyond the late twenties.
Inheritance
X-linked recessive. Duchenne primarily affects boys,
who inherit the disease through their mothers.
Women can be carriers of Duchenne but usually exhibit
no symptoms.
Caused by an absence of dystrophin, a protein that
helps keep muscle cells intact.
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Becker
Usual Age of Onset
2 to 16 years
Disease Characteristics
Symptoms almost identical to Duchenne yet less
severe.
Affects pelvis, upper arms, and upper legs
first.
Becker progresses more slowly than Duchenne.
Survival runs well into middle age.
Inheritance
X-linked recessive. Becker primarily affects boys
and men, who inherit the disease through their
mothers.
Women can be carriers but usually exhibit
no symptoms.
Becker disease occurs because there is an insufficient
production of dystrophin,
a protein that helps keep
muscle cells intact.
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Limb-Girdle
Usual Age of Onset
Late childhood to middle age
Disease Characteristics
Weakness and wasting, affecting shoulder girdle and
pelvic girdle first.
Disease usually progresses slowly.
Variable cardiopulmonary complications may occur in later
stages.
Inheritance
Some types are autosomal dominant, meaning LGMD
is inherited from one parent.
Other types are autosomal recessive and occur when a faulty gene is inherited from each parent.
Limb-Girdle is caused by a mutation in any of at least
15 different genes that
affect proteins necessary
for muscle function.
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Facioscapulo-humeral
(Landouzy-Dejerine)
Usual Age of Onset
Childhood to early adulthood
Disease Characteristics
Facial muscle weakness, with weakness and wasting
of the shoulders and the upper arms.
Progressing slowly with some periods of rapid deterioration, disease may span many decades.
Inheritance
Autosomal dominant; the disease may be inherited through either the father or the mother.
A missing piece of DNA on chromosome 4 causes Facioscapulo-humeral.
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Congenital
Usual Age of Onset
At birth or infancy
Disease Characteristics
Generalized muscle weakness, with possible joint contractures resulting from shortening of muscles.
Disease progresses very slowly. Weakness is variable.
Inheritance
Autosomal recessive; the disease is inherited through
both parents.
Congenital disease is caused by genetic mutations affecting some of the proteins necessary
for muscles. Sometimes proteins are affected for the eyes and or the brain.
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Oculopharyngeal
Usual Age of Onset
Early adulthood to middle age
Disease Characteristics
First affects muscles of eyelids and throat.
While progression is slow, throat muscles weakening in time causes swallowing difficulties.
Inheritance
May be autosomal dominant, meaning oculopharyngeal
is
inherited from one parent; or autosomal recessive,
occurring when a faulty gene is inherited from each
parent.
Oculopharyngeal develops because a faulty gene for
poly(A)-binding protein 1 (PABPN1), which is suspected
to lead
to production of extra chemical material. The chemical material causes formation of clumps in the muscle cells.
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Distal
Usual Age of Onset
Early adulthood to middle age
Disease Characteristics
Weakness and wasting of muscles of the hands,
forearms, and lower legs.
Progresses slowly and is rarely life-threatening.
Inheritance
May be autosomal dominant, meaning a faulty gene is inherited from one parent; or autosomal recessive,
occurring when a faulty gene is inherited from each
parent.
Distal disease is caused by a mutation in any of at least seven genes that affect proteins necessary
to the
function of muscles.
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Emery-Dreifuss
Usual Age of Onset
Childhood to early teens
Disease Characteristics
Weakness and wasting of shoulder, upper arm, and
shin muscles. Joint contractures are common.
Disease progresses slowly, with cardiac complications common.
Inheritance
Can be X-linked recessive, primarily affecting males,
who inherit the disease through their mothers.
Another type is autosomal dominant, meaning it can
be inherited through either parent; an autosomal
recessive type occurs when a faulty gene is inherited
from each parent
Mutations in the genes that produce emerin,
lamin A or lamin C, proteins in the membrane that surrounds the nucleus of each muscle cell
causes Emery-Dreifuss.
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Neuromuscular Diseases included in MDA's Programs
Muscular Dystrophies
Motor Neuron Diseases
Inflammatory Myopathies
Diseases of Neuromuscular Junction
Diseases of Peripheral Nerves
Metabolic Diseases of Muscle
Myopathies Due to Endocrine Abnormalities
Other Myopathies
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