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Amyotrophic Lateral Sclerosis
(ALS, Lou Gehrig's Disease)
Usual Age of Onset
Adulthood
Disease Characteristics
Progressive wasting and weakness of all voluntary muscles, with cramps and muscle twitches common.
ALS first affects legs, arms, and/or throat muscles.
Survival rarely exceeds five years after onset, without respiratory intervention.
Inheritance
Primarily sporadic, but can be autosomal dominant and,
in very rare cases, autosomal recessive
The cause of ALS is generally unknown, although genetic factors are thought to play a role;
about 10 percent of cases are clearly genetic, with a family history.
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Infantile Progressive Spinal Muscular Atrophy
(SMA Type 1, Werdnig-Hoffman)
Usual Age of Onset
Birth to 3 months
Disease Characteristics
Generalized muscle weakness, weak cry, trouble swallowing and sucking, and breathing distress.
Life span rarely exceeds age 2.
Inheritance
Autosomal recessive; a faulty gene must be inherited
from
each parent.
Infantile progressive spinal muscular atrophy
is
caused by a deficiency of a motor neuron protein called SMN,
for survival
of motor neurons, resulting from
a faulty gene on chromosome 5.
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Intermediate Spinal Muscular Atrophy
(SMA Type 2)
Usual Age of Onset
6 months to 3 years
Disease Characteristics
Weakness in arms, legs, upper and lower torso, often with skeletal deformities.
Disease progresses rapidly.
Respiratory problems can
shorten life.
Inheritance
Autosomal recessive; a faulty gene must be inherited from
each parent.
A deficiency of a motor neuron protein called SMN, for survival of motor neurons,
resulting from a faulty gene on chromosome 5 causes intermediate spinal muscular atrophy.
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Juvenile Spinal Muscular Atrophy
(SMA Type 3, Kugelberg-Welander)
Usual Age of Onset
1 to 15 years
Disease Characteristics
Weakness in leg, hip, shoulder, arm, and respiratory muscles.
Disease progresses slowly. Life span is unaffected.
Inheritance
Autosomal recessive; a faulty gene must be inherited from
each parent.
Juvenile spinal muscular atrophy is caused by
a deficiency of
a motor neuron protein called
SMN, for survival of motor
neurons, resulting from a faulty gene
on chromosome 5.
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Adult Spinal Muscular Atrophy
(SMA - Adult)
Usual Age of Onset
18 to 50 years
Disease Characteristics
Generalized muscle weakness with muscle twitches common.
Disease progression varies.
Inheritance
Autosomal recessive; a faulty gene must be inherited from
each parent.
A deficiency of a motor neuron protein called SMN, for
survival of motor neurons,
resulting from a faulty gene on chromosome 5 causes adult spinal muscular atrophy.
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Spinal-Bulbar Muscular Atrophy
(Kennedy's Disease and X-Linked SBMA)
Usual Age of Onset
15 to 60 years
Disease Characteristics
Weakness of limb muscles, especially legs, and muscles involved in talking,
chewing, and swallowing.
Occurs in men. Slowly progressive over decades.
Inheritance
X-linked recessive (Usually affects only men; - female carriers may have a mild form.)
Spinal-bulbar muscular atrophy occurs because a genetic mutation that affects an X-chromosome gene for
the androgen receptor protein,
apparently making it toxic to nerve cells.
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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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