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$Unique_ID{BRK04009}
$Pretitle{}
$Title{Motor Neuron Disease}
$Subject{Motor Neuron Disease Motor Neurone Disease Motor Neuron Syndrome
Motoneuron Disease Motoneurone Disease Amyotrophic Lateral Sclerosis (ALS or
Lou Gehrig's Disease) Primary Lateral Sclerosis Werdnig-Hoffmann Disease
(Infantile Spinal Muscular Atrophy) Kugelberg-Welander Syndrome (Juvenile
Spinal Muscular Atrophy) Spinal Muscular Atrophy Progressive Bulbar Palsy
(Duchenne's Paralysis) Benign Focal Amyotrophy Benign Congenital Hypotonia
Nemaline Myopathy }
$Volume{}
$Log{}

Copyright (C) 1989, 1992 National Organization for Rare Disorders, Inc.

656:
Motor Neuron Disease

** IMPORTANT **
It is possible that the main title of the article (Motor Neuron Disease)
is not the name you expected.  Please check the SYNONYM listing to find the
alternate names and disorder subdivisions covered by this article.

Synonyms

     Motor Neurone Disease
     Motor Neuron Syndrome
     Motoneuron Disease
     Motoneurone Disease

Disorder Subdivisions:

     Amyotrophic Lateral Sclerosis (ALS or Lou Gehrig's Disease)
     Primary Lateral Sclerosis
     Werdnig-Hoffmann Disease (Infantile Spinal Muscular Atrophy)
     Kugelberg-Welander Syndrome (Juvenile Spinal Muscular Atrophy)
     Spinal Muscular Atrophy
     Progressive Bulbar Palsy (Duchenne's Paralysis)
     Benign Focal Amyotrophy

Information on the following diseases can be found in the Related
Disorders section of this report:

     Benign Congenital Hypotonia
     Nemaline Myopathy

General Discussion

** REMINDER **
The information contained in the Rare Disease Database is provided for
educational purposes only.  It should not be used for diagnostic or treatment
purposes.  If you wish to obtain more information about this disorder, please
contact your personal physician and/or the agencies listed in the "Resources"
section of this report.

Motor Neuron Disease is a group of serious disorders characterized by
progressive degeneration of motor neurons (neurons combine to form nerves).
Motor neurons control the behavior of muscles.  Motor Neuron Diseases may
affect the upper motor neurons, nerves that lead from the brain to the
medulla (a part of the brain stem) or to the spinal cord, or the lower motor
neurons, nerves that lead from the spinal cord to the muscles of the body, or
both.  Spasms and exaggerated reflexes indicate damage to the upper motor
neurons.  A progressive wasting (atrophy) and weakness of muscles which have
lost their nerve supply indicate damage to the lower motor neurons.

Symptoms

Generally, a Motor Neuron Disease is characterized by muscle weakness,
wasting (atrophy), and normal intellectual functioning.  For specific
symptoms, see each of the forms of Motor Neuron Disease in the Disorder
Subdivision section.  The different forms affect certain motor neurons, thus
certain symptoms are associated with each of them.  Also, there may be
overlap of the different forms, thus overlap of their associated symptoms.

DISORDER SUBDIVISIONS
Debate still exists on whether there are distinct forms of Motor Neuron
Disease or if they are variants of Amyotrophic Lateral Sclerosis.  Symptoms
of the different forms may overlap.

AMYOTROPHIC LATERAL SCLEROSIS (LOU GEHRIG'S DISEASE) or 'ALS' is the most
well known Motor Neuron Disease.  It affects both the upper and lower motor
neurons.  Clumsy hands, weakness in the legs, or difficulty in swallowing and
slow speech may be the first signs.  The disease progresses to involve
muscles all over the body.  Coughing, difficulty in breathing, progressive
wasting and weakness, and spasticity or stiffness of muscles may occur.  ALS
affects adults, men more than women, usually between the ages of 40 and 70.
(For more information on this disorder, choose "ALS" as your search term in
the Rare Disease Database).

PRIMARY LATERAL SCLEROSIS affects adults.  It is characterized by
progressive degeneration of the upper motor neurons.  Difficulty in speech
and swallowing, semi- or complete paralysis of the legs and/or arms, and
muscle twitching and spasticity may occur.  Males and females are affected
equally by this rare disease.  (For more information on this disorder, choose
"Primary Lateral Sclerosis" as your search term in the Rare Disease
Database.)

WERDNIG-HOFFMANN DISEASE (INFANTILE SPINAL MUSCULAR ATROPHY) is a severe
Motor Neuron Disease that affects infants.  It is characterized by weakness,
twitching, and wasting of the muscles of the body.  Breathing, excretory, and
feeding difficulties may occur.  It is a hereditary form of Motor Neuron
Disease.  The more serious and progressive form of Werdnig-Hoffmann Disease
becomes evident within the first few months of life.  This rare disease is
estimated to occur in 1 out of every 1,000,000 live births per year.  It
affects males and females equally.  (For more information on this disorder,
choose "Werdnig-Hoffmann" as your search term in the Rare Disease Database).

KUGELBERG-WELANDER SYNDROME (JUVENILE SPINAL MUSCULAR ATROPHY) is a
serious disorder usually appearing in the first ten to twenty years of life.
It is characterized by muscle wasting and weakness in the arms and legs,
twitching, difficulties in walking, and eventual loss of reflexes.  The
muscles of the eye, heart, and anal sphincter (ring of muscles that prevents
passage of feces) may be affected causing vision problems, irregular
heartbeat, and loss of bowel control.  Kugelberg-Welander is a hereditary
form of Motor Neuron Disease.  This rare disease tends to have a higher
incidence and severity in males than in females.  (For more information on
this disorder, choose "Kugelberg-Welander" as your search term in the Rare
Disease Database).

PROGRESSIVE SPINAL MUSCULAR ATROPHY is a slowly progressive Motor Neuron
Disease.  Muscle weakness and wasting may begin in the hands and eventually
affect the arms, shoulders, legs, and the rest of the body.  Muscle twitching
may occur in the limbs and tongue.

PROGRESSIVE BULBAR PALSY is a severe Motor Neuron Disease usually
occurring in childhood.  It affects the muscles of the tongue, lips, palate,
pharynx (back of the throat), and larynx ('voice-box').  Weakness and wasting
of these muscles may cause difficulties in chewing, swallowing, and talking.
Respiratory problems may also occur.

Causes

The exact cause of most types of Motor Neuron Disease is not known.

Werdnig-Hoffmann Disease, Kugelberg-Welander Syndrome, and Progressive
Bulbar Atrophy are forms of Motor Neuron Diseases that effect children or
young adults.  They are inherited as an autosomal recessive trait.

Human traits including the classic genetic diseases are the product of
the interaction of two genes for that condition, one received from the father
and one from the mother.  In recessive disorders, the condition does not
appear unless a person inherits the same defective gene for the same trait
from each parent.  If one receives one normal gene and one gene for the
disease, the person will be a carrier for the disease, but usually will show
no symptoms.  The risk of transmitting the disease to the children of a
couple, both of whom are carriers for a recessive disorder, is twenty-five
percent.  Fifty percent of their children will be carriers, but healthy as
described above.  Twenty-five percent of their children will receive both
normal genes, one from each parent, and will be genetically normal.

Affected Population

The affected populations of the different forms of Motor Neuron Disease
varies.  In general, all forms are rare.  For more information, see the
specific forms in the Disorder Subdivisions section.

Related Disorders

Symptoms of the following disorders can be similar to those of Motor Neuron
Disease.  Comparisons may be useful for a differential diagnosis:

Benign Congenital Hypotonia is a nonprogressive neuromuscular disorder
affecting newborns.  It is characterized by muscle weakness or 'floppiness.'
The cause of this disorder is not known and symptoms may improve with age.
(For more information on this disorder, choose "Hypotonia" as your search
term in the Rare Disease Database).

Nemaline Myopathy is a hereditary muscular disease affecting newborns.  It
is characterized by muscle weakness or 'floppiness.'  The limbs and trunk are
affected which may affect posture.  Reflexes may be absent.  There may be
swallowing and breathing problems.  Although progression occurs, some
improvement may be seen as the muscles grow.  (For more information on this
disorder, choose "Nemaline" as your search term in the Rare Disease
Database).

Symptoms of other neuromuscular diseases may mimic Motor Neuron Disease.
Examination by a neurologist is necessary to determine if the patient has
motor neuron disease or another type of neuromuscular disease.

Therapies:  Standard

Treatment of Motor Neuron Disease is symptomatic and supportive.

Certain drugs may be used to control muscle symptoms:  baclofen for
spasticity, quinine for cramps, diazepam for muscular contractions, and
pyridostigmine to improve nerve-to-muscle message transmission.

Various respiratory aids can be used to help a patient breathe.  When
swallowing becomes difficult, nutrition can be maintained by the use of
various devices or by the use of softer more nutritious foods.  Methods that
help control excess saliva if the patient has difficulty swallowing may also
be used.

Devices that help the patient continue daily activities such as braces,
hand splits, limb supports, or a wheelchair are important.  Bedridden
patients can be made more comfortable with sheepskins or water mattresses.

Genetic counseling may be of benefit to patients and their families with
a hereditary form of Motor Neuron Disease.

Therapies:  Investigational

Scientists are conducting extensive ongoing research on Motor Neuron Diseases
in the areas of nerve growth factors, axonal transport, androgen receptors in
motor neurons, DNA/RNA changes, and metabolic studies of the neuromuscular
junction.  Several drug studies are underway to learn if pharmaceuticals may
slow the progression of these disorders.

Syntex-Synergen Neuroscience of Boulder, CO, is sponsoring an orphan
product for the treatment of motor neuron diseases.  The chemical name is
ciliary neurotrophic factor, recombinant human.

This disease entry is based upon medical information available through
June 1992.  Since NORD's resources are limited, it is not possible to keep
every entry in the Rare Disease Database completely current and accurate.
Please check with the agencies listed in the Resources section for the most
current information about this disorder.

Resources

For more information on Motor Neuron Disease, please contact:

     National Organization for Rare Disorders (NORD)
     P.O. Box 8923
     New Fairfield, CT  06812-1783
     [phone]

     NIH/National Institute of Neurological Disorders & Stroke (NINDS)
     9000 Rockville Pike
     Bethesda, MD  20892
     [phone]
     [phone]

     The Amyotrophic Lateral Sclerosis Society
     21021 Ventura Blvd., Suite 321
     Woodland Hills, CA  91364
     [phone]

For information about Motor Neuron Diseases that occur during childhood:

     Families of Spinal Muscular Atrophy
     P.O. Box 1465
     Highland Park, IL  60035
     [phone]

For genetic information and genetic counseling referrals for inherited
Motor Neuron Diseases:

     March of Dimes Birth Defects Foundation
     1275 Mamaroneck Avenue
     White Plains, NY  10605
     [phone]

     NIH/National Center for Education in Maternal and Child Health (NCEMCH)
     38th & R Streets, NW
     Washington, DC  20057
     [phone]

References

MENDELIAN INHERITANCE IN MAN, 7th ed.:  Victor A. McKusick; Johns Hopkins
University Press, 1986.  Pp.  683.

INTERNAL MEDICINE, 2nd Ed.:  Jay H. Stein, ed.-in-chief; Little, Brown
and Co., 1987.  Pp. 2243-2244.