CD-ROM Today 1996 January/CD-ROM Today 1996 January.iso/dp/0377/03777.txt

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$Unique_ID{BRK03777}
$Pretitle{}
$Title{Glycogen Storage Disease VIII}
$Subject{Glycogen Storage Disease VIII Glycogenosis Type VIII Hepatic
Phosphorylase Kinase Deficiency Phosphorylase Kinase Deficiency of Liver PYKL
Forbes Disease Andersen Disease Hers Disease}
$Volume{}
$Log{}

Copyright (C) 1987, 1989, 1991 National Organization for Rare Disorders,
Inc.

400:
Glycogen Storage Disease VIII

** IMPORTANT **
It is possible the main title of the article (Glycogen Storage Disease
VIII) is not the name you expected.  Please check the SYNONYMS listing on
the next page to find alternate names, disorder subdivisions, and related
disorders covered by this article.

Synonyms

     Glycogenosis Type VIII
     Hepatic Phosphorylase Kinase Deficiency
     Phosphorylase Kinase Deficiency of Liver
     PYKL

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

     Von Gierke Disease
     Forbes Disease
     Andersen Disease
     Hers 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 of this report.


Glycogen Storage Disease VIII is a sex-linked genetic disorder caused by
a deficiency of the enzyme liver phosphorylase kinase.  The disorder is
characterized by slightly low blood sugar (hypoglycemia).  Excess amounts of
glycogen (the stored form of energy that comes from carbohydrates) are
deposited in the liver, causing enlargement of the liver (hepatomegaly).

Symptoms

Glycogen Storage Disease VIII is usually a mild disorder.  Symptoms may
include an enlarged liver, increased liver glycogen (the stored form of
energy from carbohydrates), and mild hypoglycemia (low blood sugar).
Although inflammation of the liver may sometimes occur, liver function is
usually normal and the disorder may be undetected throughout life.

Causes

Glycogen Storage Disease VIII is a sex-linked genetic disorder caused by a
deficiency of the enzyme liver phosphorylase kinase.  This deficiency causes
deposits of excessive amounts of glycogen in the liver.  (X-linked recessive
traits are expressed predominantly in males.  Females carry the gene on one
of their two X chromosomes.  The second X chromosome will usually "mask" the
trait, however, if the trait is x-linked recessive.  The trait is expressed
in males because instead of a second X chromosome, they have a Y chromosome
which does not "mask" the harmful gene.  Affected males cannot transmit the
trait to their sons.)

Affected Population

All Glycogen Storage Diseases together affect less than 1 in 40,000 persons
in the United States.  Glycogen Storage Disease VIII affects more males than
females and usually begins during infancy; about 10% of patients with this
disorder are females with only very mild symptoms.

Related Disorders

Glycogen Storage Diseases are caused by inborn errors of metabolism in which
the balance between stored energy (glycogen) and available energy (sugar or
glucose) is disturbed.  Too much glycogen tends to be stored in the liver
and muscles and too little sugar is available in the blood.

Symptoms of the following diseases may be similar to Glycogen Storage
Disease VIII.  Comparisons may be useful for a differential diagnosis:

Von Gierke Disease (Glycogenosis I) is a glycogen storage disease.  This
hereditary metabolic disorder is caused by an inborn lack of either the
enzyme glucose-6-phosphatase or the enzyme glucose-6-phosphate translocase.
These enzymes are needed to convert the main carbohydrate storage material
(glycogen) into sugar (glucose) which the body uses for its energy needs.  A
deficiency of these enzymes causes deposits of excess glycogen in the liver
and kidney cells.

Forbes Disease (Glycogenosis III; Cori Disease) is another genetic
glycogen storage disease.  This disorder is caused by a lack of a debrancher
enzyme (amylo-1,6-glucosidase).  This enzyme deficiency causes excess
glycogen (the main carbohydrate storage material) to be deposited in the
liver and muscles.  The heart may be involved in some cases.

Andersen Disease (Glycogenosis VI) is a glycogen storage disease
inherited through recessive genes.  Symptoms of this disorder are caused by
a lack of a brancher enzyme (alpha-1,4-glucan 6-glucosyltransferase).  The
lack of this enzyme causes an abnormality in the structure of the main
carbohydrate storage material (glycogen).  Andersen Disease is characterized
by scarring of the liver (cirrhosis) sometimes leading to liver failure.

Hers Disease is a genetic form of mild glycogen storage disease.  The
disorder is caused by a deficiency of the enzyme liver phosphorylase.  Hers
Disease is characterized by enlargement of the liver (hepatomegaly), low
blood sugar (hypoglycemia), elevated levels of acetone and other ketone
bodies in the blood (ketosis), and growth retardation.  Symptoms are not
always evident during childhood, so children are usually able to lead normal
lives.  In other cases symptoms may be more severe.

For more information on the above disorders, choose "Gierke," "Forbes,"
"Andersen," and "Hers" as your search terms in the Rare Disease Database.

Therapies:  Standard

Treatment is usually not necessary for this disorder in its mild form.

Therapies:  Investigational

Genetic counseling will be helpful for families of children with Glycogen
Storage Disease VIII.

Dr. Y.T. Chen at Duke University Medical Center, at the request of the
Glycogen Storage Disease Association, is collecting DNA from patients with
Glycogen Storage Disease Type I to form a DNA bank for GSDI.  Interested
patients may contact the Glycogen Storage Diseases Association for further
information.  The address and phone number of the organization are listed in
the Resources section of this report.

This disease entry is based upon medical information available through
February 1991.  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 Glycogenosis Type VIII, please contact:

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

     Association for Glycogen Storage Diseases
     Box 896
     Durant, IA  52747
     [phone]

     Research Trust for Metabolic Diseases in Children
     Golden Gates Lodge, Weston Rd.
     Crewe CW1 1XN, England
     Telephone:  [phone]

     National Digestive Diseases Information Clearinghouse
     Box NDDIC
     Bethesda, MD  20892
     [phone]

For information on genetics and genetic counseling referrals, please

     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

GLYCOGEN STORAGE DISEASES:  A PATIENT-PARENT HANDBOOK:  Ed. by R. Rodney
Howell; University of Texas Health Science Center, 1980.  Pp. 32-33.