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$Unique_ID{BRK04092}
$Pretitle{}
$Title{Pelizaeus-Merzbacher Brain Sclerosis}
$Subject{Pelizaeus-Merzbacher Brain Sclerosis Diffuse Familial Brain Sclerosis
Aplasia, Axialis Extracorticales Congenita Sudanophilic Leukodystrophy
Pelizaeus-Merzbacher Disease}
$Volume{}
$Log{}
Copyright (C) 1986, 1987, 1990 National Organization for Rare Disorders,
Inc.
158:
Pelizaeus-Merzbacher Brain Sclerosis
** IMPORTANT **
It is possible that the main title of the article (Pelizaeus-Merzbacher
Brain Sclerosis) is not the name you expected. Please check the SYNONYM
listing to find the alternate names and disorder subdivisions covered by this
article.
Synonyms
Diffuse Familial Brain Sclerosis
Aplasia, Axialis Extracorticales Congenita
Sudanophilic Leukodystrophy
Pelizaeus-Merzbacher Disease
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.
Pelizaeus-Merzbacher Brain Sclerosis is a progressive, degenerative
central nervous system disease in which coordination, motor abilities, and
intellectual function deteriorate. It often progresses rapidly, although
some patients have lived to old age. The disorder almost always occurs in
males.
Symptoms
Evidence of Pelizaeus-Merzbacher Brain Sclerosis usually appears in early
infancy, although onset is later in one form. The child fails to develop
normal control of head movements and grows slowly. The eyes wander aimlessly
or in circular movements. Later symptoms include tremor, various involuntary
movements, grimacing, weakness, unsteady gait, and muscle contractures. In
cases with later onset, speech usually deteriorates. As time progresses,
legs and then the arms can become spastic, and mental functions deteriorate.
Some patients experience convulsions. Skeletal deformation may result from
abnormal muscular stresses on bone.
Pathologic changes in the brain consist of destruction of the myelin
sheath (a kind of insulation) surrounding the axons of the nerve cells (the
white matter of the brain). These changes occur in subcortical parts of the
cerebrum, the cerebellum, and the brainstem. Breakdown products of myelin
also accumulate in the brain. These stain characteristically.
Causes
The reasons for the degeneration of the white matter of the brain are not
understood. Pelizaeus-Merzbacher Brain Sclerosis is hereditary. Infantile
forms are either autosomal recessive or X-linked.
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 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.
A form with adult onset is autosomal dominant. 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.
Affected Population
One form of Pelizaeus-Merzbacher Brain Sclerosis affects male infants. Other
forms affect infants or adults of both sexes.
Related Disorders
Pelizaeus-Merzbacher Brain Sclerosis belongs to a group of degenerative brain
diseases known as leukodystrophies. These are characterized by destruction
of the white matter of the brain, and include such diseases as Krabbe's,
Schilder's, Adrenoleukodystrophy, and several others.
Therapies: Standard
Treatment for Pelizaeus-Merzbacher Brain Sclerosis is symptomatic. Supportive
care, including emotional support for family members, is recommended as
needed.
Therapies: Investigational
Current research is directed toward the identification of the gene that
causes Pelizaeus-Merzbacher Brain Sclerosis. When the gene is located,
scientists may be able to determine the exact cause of the symptoms, which
will hopefully lead to development of new treatments for this disease.
This disease entry is based upon medical information available through
January 1990. 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 Pelizaeus-Merzbacher Brain Sclerosis, please
contact:
National Organization for Rare Disorders (NORD)
P.O. Box 8923
New Fairfield, CT 06812-1783
(203) 746-6518
United Leukodystrophy Foundation
2304 Highland Drive
Sycamore, IL 60178
(815) 895-3211
(800) 728-5483
NIH/National Institute of Neurological Disorders & Stroke (NINDS)
9000 Rockville Pike
Bethesda, MD 20892
(301) 496-5751
(800) 352-9424
International Tremor Foundation
360 W. Superior St.
Chicago, IL 60610
(312) 664-2344
Research Trust for Metabolic Diseases in Children
Golden Gates Lodge, Weston Rd.
Crewe CW1 1XN, England
Telephone: (0270) 250244
Association Europeenne contre les Leucodystrophies
7 Rue Pasteur
54000 NANCY
France
References
CECIL TEXTBOOK OF MEDICINE, 18th ed.: James B. Wyngaarden, and Lloyd H.
Smith, Jr., Eds.: W. B. Saunders Co., 1988. P. 2216.