Ron.Rothenberg@f460.n101.z1.fidonet.org (Ron Rothenberg) (07/19/90)
Index Number: 9306
Courtesy of NORD (National Organization for Rare Diseases) database.
Hope you find this helpful, Ralph.
Note also the Canadian and U.S. support groups.
Synonyms
--------------------------------
Peroneal Muscular Atrophy
CMT
Hereditary Sensory Motor Neuropathy
HSMN
Information on the following diseases can be found in the Related Disorders
section of this report.
Dejerine-Sottas Disease
Hereditary Sensory Radicular Neuropathy
Refsum Syndrome
Familial Amyloid Neuropathy
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.
Copyright (C) 1986, 1988, 1989 National Organization for Rare Disorders, Inc.
Charcot-Marie-Tooth disease is a hereditary neurological disorder,
characterized by weakness and atrophy, primarily in the legs. Disappearance
of the fatty shield surrounding the nerves (segmental demyelination) of
peripheral nerves and associated degeneration of part of the nerve cells
(axons) characterize this disorder.
Symptomatology
--------------------------------
Symptoms of Charcot-Marie-Tooth disease usually begin gradually sometime
between middle childhood and age 30. Muscle atrophy and weakness are most
prominent in the legs and the small muscles of the hands. The most
incapacitating symptom of CMT is "foot drop", producing a slapping gait. Pain
and unusual sensations (paresthesias) rarely may be present in the affected
limbs. A decrease in vibration, pain and thermal sensation in the hand, foot
and lower part of the leg (glove and stocking pattern) is common. Stretch
reflexes are usually absent. The disease is slowly progressive, but may
arrest spontaneously. Patients may remain active for years and live a normal
life span.
For more information, see the newsletter of Charcot-Marie-Tooth International
in the Newsletter section of NORD Services.
Etiology
--------------------------------
CMT disease is usually inherited through an autosomal dominant transmission.
It may also be inherited through a recessive hereditary mechanism or
sex-linked recessive inheritance.
(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 dominant disorders, a single copy of the disease gene (received from either
the mother or father) will be expressed "dominating" the normal gene and
resulting in appearance of the disease. The risk of transmitting the disorder
from affected parent to offspring is 50% for each pregnancy regardless of the
sex of the resulting child.)
In recessive disorders, the condition does not appear unless a person inherits
the same defective gene 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.)
X-linked recessive disorders are conditions which are coded on the X
chromosome. Females have two X chromosomes, but males have one X chromosome
and one Y chromosome. Therefore in females, disease traits on the X
chromosome can be masked by the normal gene on the other X chromosome. Since
males have only one X chromosome, if they inherit a gene for a disease present
on the X, it will be expressed. Men with X-linked disorders transmit the gene
to all their daughters, who are carriers, but never to their sons. Women who
are carriers of an X-linked disorder have a fifty percent risk of transmitting
the carrier condition to their daughters, and a fifty percent risk of
transmitting the disease to their sons.)
Affected Population
--------------------------------
Onset of CMT disease is usually between middle childhood and age 30. It
affects an equal number of males and females.
Related Disorders
--------------------------------
Dejerine-Sottas disease (Hypertrophic Interstitial Neuropathy) is a rare
disorder in which proliferation of the cells of the membrane around certain
nerve fibers (neurilemma or sheath of Schwann) causes excessive growth
(hypertrophy) of the peripheral nerve roots and nerve clusters (ganglia), with
destruction of part of the nerve cell (axon). The age of onset, clinical
findings and prognosis are similar to those of CMT disease. (For more
information, chose "Dejerine" as your search term in the Rare Disease
Database.)
Hereditary sensory radicular neuropathy is a dominant hereditary disorder
characterized initially by pain and loss of thermal sensation in the foot and
lower leg. Later, attacks of sharp pain throughout the body may occur with
weakness and ulcers on toes.
Refsum Syndrome (Phytanic Acid Storage Disease) is a rare recessive genetic
disorder of fat (lipid) metabolism characterized by peripheral neuropathy,
impaired muscle coordination (ataxia), Retinitis Pigmentosa (RP), deafness,
and bone and skin changes. It is associated with marked accumulation of
phytanic acid in the blood plasma and tissues. The disorder may be due to the
absence of phytanic acid hydroxylase, an enzyme needed for the metabolism of
phytanic acid. Prolonged treatment with a diet lacking in phytanic acid can
be therapeutic. (For more information, choose "Refsum" and "RP" as your
search terms in the Rare Disease Database.)
Familial Amyloid Neuropathy is a very rare genetic disorder inherited through
autosomal dominant genes. It is characterized by abnormal accumulations of
amyloid in the peripheral nerves. The location of the specific genetic
mutation that causes this disorder is unknown.
Therapies: Standard
--------------------------------
Treatment of CMT disease is symptomatic and supportive. Vocational
counseling, anticipating progression of the disorder, may be useful for young
patients. Use of braces can help correct foot drop. Orthopedic surgery to
stabilize the foot may be of value.
Therapies: Investigational
--------------------------------
Research is ongoing into possible new therapies for Charcot-Marie-Tooth
Disease. For the most current information, please contact the agencies listed
in the Resources section of thisa report.
This disease entry is based upon medical information available through
December 1989. 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 Carcot-Marie-Tooth Disease, please contact:
National Organization for Rare Disorders (NORD)
P.O. Box 8923
New Fairfield, CT 06812
(203) 746-6518
Charcot-Marie-Tooth International
1 Spring Bank Dr.
St. Catherines, Ontario L2S 2K1
Canada
(416) 687-3630
NIH/National Institute of Neurological Disorders & Stroke (NINDS)
9000 Rockville Pike
Bethesda, MD 20892
(301) 496-5751
For genetic information and genetic counseling referrals, please contact:
March of Dimes Birth Defects Foundation
1275 Mamaroneck Avenue
White Plains, NY 10605
(914) 428-7100
National Center for Education in Maternal and Child Health
38th & R Streets
Washington, DC 20057
(202) 625-8400
National Foundation for Peroneal Muscular Atrophy (CMT)
Crozer Mills Enterprise Center
600 Upland Ave.
Upland, PA 19105
... Early to bed, early to rise, work like hell, and advertise. - L.J. Peter
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