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$Unique_ID{BRK04045}
$Pretitle{}
$Title{Neuropathy, Giant Axonal}
$Subject{Neuropathy Giant Axonal GAN Giant Axonal Neuropathy Axonal Neuropathy
Giant Congenital Giant Axonal Neuropathy Giant Axonal Disease Childhood Giant
Axonal Neuropathy Seitelberger Disease Incontinentia Pigmenti }
$Volume{}
$Log{}

Copyright (C) 1990 National Organization for Rare Disorders, Inc.

802:
Neuropathy, Giant Axonal

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

Synonyms

     GAN
     Giant Axonal Neuropathy
     Axonal Neuropathy, Giant
     Congenital Giant Axonal Neuropathy
     Giant Axonal Disease
     Childhood Giant Axonal Neuropathy

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

     Seitelberger Disease
     Incontinentia Pigmenti

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.

Giant Axonal Neuropathy is a genetic disorder that first appears during
infancy.  Major symptoms may include kinky hair, unusual leg posture, poor
vision, impaired muscle coordination (ataxia) and weakness, and degenerative
mental functioning (dementia).

Symptoms

Giant Axonal Neuropathy (GAN) may be characterized by symptoms such as loss
of sensation in the legs and feet, impaired muscle coordination (ataxia) and
weakness, decreased reflexes (hyporeflexia), and poor vision.  Other senses
such as hearing may also be affected.  Mental retardation or seizures may
occur.  Tightly curled kinky hair, which may be extremely pale, is
characteristic of GAN but is not present in all patients.  Degenerative
mental changes (dementia) may occur as the disorder progresses.  Other
symptoms may include unusual leg posture, involuntary rapid movements of the
eyeball (nystagmus), wasting away of muscles possibly in all four limbs
(amyotrophy), muscle twitches (fasciculations), and difficulty in
articulation of speech (dysarthria).

Giant Axonal Neuropathy is present at birth.  Onset of the disorder
occurs in infancy or very early childhood and it is slowly progressive.  Both
the central and peripheral nervous systems are involved.  The central nervous
system is comprised of the brain and spinal cord, while the peripheral
nervous system spreads out from the brain and spinal cord to all other areas
of the body.

In Giant Axonal Neuropathy, a part of the nerve cell called the axon
swells up with abnormal deposits of tiny threads of protein called
"neurofilaments."  Other filaments, called "intermediate filaments (IFS)",
collapse into large clusters in a variety of cells such as nerves, muscles,
and connective tissue cells and cells that produce colors (pigments).  This
causes degeneration and abnormal functioning especially affecting the
peripheral nervous system.

As the disorder progresses the central nervous system becomes involved.
Occurring within the brain and spinal cord is the formation of fibrous
deposits known as Rosenthal fibers.  The corticospinal tract (the area around
the spinal cord where nerve impulses direct the movement of muscles),
cerebellum (the area of the brain concerned especially with muscle
coordination and balance), and the white matter of the brain become affected.
There is a progressive loss of axons within nerve cells as the disorder
progresses.

Diagnosis can be made by sural nerve biopsy.

Causes

Giant Axonal Neuropathy is a genetic disorder with an autosomal recessive
inheritance.  Human traits, including the classic genetic diseases, are the
product of the interaction of two genes, 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

Giant Axonal Neuropathy is a rare disorder present at birth.  It affects
males and females in equal numbers.  Onset of the disorder occurs in infancy
or very early childhood.

Related Disorders

Symptoms of the following disorders can be similar to those of Giant Axonal
Neuropathy.  Comparisons may be useful for a differential diagnosis:

Seitelberger Disease is an inherited central nervous system disorder
usually beginning before the age of two years.  Children with Seitelberger
Disease may experience difficulty in walking and/or speaking.  A decreased
sensitivity to pain may develop in the legs and trunk.  Coordination may
become impaired, and decreased muscle tone ("floppiness"), muscle spasms
(spasticity) and/or weakening of reflexes may also occur.  In later stages,
involuntary rapid eye movements, progressive vision problems and seizures can
occur.  (For more information on this disorder, choose "Seitelberger Disease"
as your search term in the Rare Disease Database).

Incontinentia Pigmenti is a genetic dermatological disorder characterized
by unusual patterns of discolored skin.  These discolorations tend to improve
with age.  Abnormal deposits of normal skin pigment (melanin) cause these
discolorations.  Other oral, visual and/or neurological symptoms may also
occur.  Extremely kinky or wooly hair (Wooly hair nevus) and an immune system
dysfunction have also been reported in a small number of patients with IP.
(For more information on this disorder, choose "Incontinentia Pigmenti" as
your search term in the Rare Disease Database).

Therapies:  Standard

Treatment of Giant Axonal Neuropathy is symptomatic and supportive.  Genetic
counseling will be of benefit for patients and their families.  Services for
visually and/or mobility impaired people may be of assistance to people with
Giant Axonal Neuropathy.

Therapies:  Investigational

This disease entry is based upon medical information available through August
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 Giant Axonal Neuropathy, please contact:

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

     Children's Brain Diseases Foundation for Research
     350 Parnassus, Suite 900
     San Francisco, CA 94117
     [phone]
     [phone]

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

For genetic information and genetic counseling referrals:

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

     Alliance of Genetic Support Groups
     35 Wisconsin Circle, Suite 440
     Chevy Chase, MD  20815
     (800) 336-GENE
     [phone]

References

MENDELIAN INHERITANCE IN MAN, 8th Ed.:  Victor A. McKusick; Johns Hopkins
University Press, 1986.  Pp. 1107.

CHILDHOOD GIANT AXONAL NEUROPATHY.  CASE REPORT AND REVIEW OF THE
LITERATURE.  R. Tandan, et al.; J Neurol Sci (Dec 1987; issue 82 (1-3)).  Pp.
205-228.

CONGENITAL GIANT AXONAL NEUROPATHY.  R.B. Kinney, et al,; Arch Pathol Lab
Med (Jul 1985; issue 109 (7)).  Pp. 639-641.

GIANT AXONAL NEUROPATHY:  A CONDITIONAL MUTATION AFFECTING CYTOSKELETAL
ORGANIZATION.  M.W. Klymkowsky, et al.; J Cell Biol (Jan 1985; issue 100
(1)).  Pp. 245-250.

GIANT AXONAL NEUROPATHY.  A REVIEW.  R.A. Ouvrier; Brain Dev (1989; issue
11 (4)).  Pp. 207-214.

GIANT AXONAL NEUROPATHY:  CENTRAL ABNORMALITIES DEMONSTRATED BY EVOKED
POTENTIALS.  A. Majnemer, et al.; Ann Neurol (Apr 1986; issue 19 (4)).  Pp.
394-396.

GIANT AXONAL NEUROPATHY:  CORRELATION OF CLINICAL FINDINGS WITH POSTMORTEM
NEUROPATHOLOGY.  C. Thomas, et al.; Ann Neurol (Jul 1987; issue 22 (1)).  Pp.
79-84.

GIANT AXONAL NEUROPATHY:  OBSERVATIONS ON A FURTHER PATIENT.  M. Donaghy,
et al.; J Neurol Neurosurg Psychiatry (Jul 1988; issue 51 (7)).  Pp.  991-
994.

GIANT AXONAL NEUROPATHY WITH INHERITED MULTISYSTEM DEGENERATION IN A
TUNISIAN KINDRED.  M. Ben Hamida, et al.; Neurology (Feb 1990; issue 40 (2)).
Pp. 245-250.