CD-ROM Today 1996 January/CD-ROM Today 1996 January.iso/dp/0376/03760.txt

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$Unique_ID{BRK03760}
$Pretitle{}
$Title{Galactosemia}
$Subject{Galactosemia Galactose-1-Phosphate Uridyl Transferase Deficiency GALT
Deficiency Lactose Intolerance Lactase Deficiency Disaccharidase Deficiency
Glucose-Galactose Malabsorption Alactasia }
$Volume{}
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Copyright (C) 1987, 1990, 1991 National Organization for Rare Disorders,
Inc.

373:
Galactosemia

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

Synonyms

     Galactose-1-Phosphate Uridyl Transferase Deficiency
     GALT Deficiency

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

     Lactose Intolerance, also known as Lactase Deficiency, Disaccharidase
     Deficiency, Glucose-Galactose Malabsorption, or Alactasia

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.


Galactosemia is an autosomal recessive hereditary disorder of
carbohydrate metabolism.  It is a rare inability to convert galactose (a
sugar contained in milk) to glucose (a different type of sugar).  The
disorder is caused by a deficiency of the enzyme "galactose-1-phosphate
uridyl transferase".

A Duarte and a Negro variant of the Galactosemia gene have been
identified.  The Duarte variant causes a milder form of the disorder, while
the Negro variant causes a more severe form.  These variants can be
distinguished by differences in galactose metabolism.  Since milk is the main
staple of an infant's diet, early diagnosis and treatment of this disorder is
absolutely essential to avoid serious lifelong disability.

Symptoms

An infant with Galactosemia appears normal at birth, but within a few days or
weeks loses its appetite (anorexia) and starts vomiting excessively.  Yellow
jaundice, enlargement of the liver (hepatomegaly), appearance of amino acids
and protein in the urine, growth failure, and ultimately accumulation of
fluid in the abdominal cavity (ascites) and other swelling (edema) may also
occur.  In time, wasting of body tissues, marked weakness and extreme weight
loss occur unless the infant is treated for the deficiency.

Children with Galactosemia who have not received early treatment may have
arrested physical and mental development with possible vision loss due to
cataracts.  In severe cases overwhelming infection can be life threatening,
but mild cases may exhibit few symptoms without serious impairment.

An infant with Galactosemia should be treated promptly by removing
galactose totally from the diet.  Liver and kidney failure, brain damage and
cataracts can be prevented through avoidance of galactose.  Children treated
with this special diet usually show satisfactory general health and growth.
They can make reasonable though often not optimal intellectual progress.
Speech and vision difficulties and some behavioral problems may occur.  Girls
with Galactosemia may develop impaired functioning of the ovaries because of
an increased level of the hormone gonadotropin; two males with Galactosemia
have also been identified who have an excessive level of gonadotropin
(hypergonadotropinism).

Causes

Galactosemia is an autosomal recessive hereditary disorder.  The most severe
form of the disorder is caused by a deficiency of the enzyme galactose-1-
phosphate uridyl transferase.  The milder form is caused by a deficiency of
the enzyme galactokinase.  These enzymes are needed for the breakdown of a
milk sugar called galactose.  Two different toxic products in galactosemic
patients have been identified:  galactitol and galactose-1-phosphate.
Galactitol causes cataracts, while galactose-1-phosphate causes the other
symptoms.

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.

Affected Population

About 1 in 80,000 live births have been estimated to be affected with
Galactosemia in Great Britain.  As many males as females are affected.

Related Disorders

Lactose Intolerance (Lactase Deficiency, Disaccharidase Deficiency, Glucose-
Galactose Malabsorption, or Alactasia) is characterized by diarrhea and
abdominal distention.  A lack of the enzyme "lactase" that normally helps to
split milk sugar (lactose) into glucose and galactose, prevents absorption of
lactose in the small bowel.  This is a very common hereditary disorder,
especially in adults with ancestry from Mediterranean, East European, and
African origin.  (For more information on this disorder, choose "Lactose
Intolerance" as your search term in the Rare Disease Database.)

However, the symptoms of Lactose Intolerance which usually get worse with
increasing age may cause discomfort without permanent disability in contrast
to Galactosemia which is a more debilitating illness.

Therapies:  Standard

Pregnant women who are carriers for Galactosemia (without symptoms) can be
detected by testing the activity of the enzyme galactose-1-phosphate uridyl
transferase in their red blood cells.  If the enzyme activity is 50% of the
normal value, the individual is a carrier.

Galactosemia can be diagnosed in infants at birth by testing the enzyme
activity level in red blood cells in a drop of blood from the umbilical cord.

Milk and milk products should be eliminated from the diet of children
with Galactosemia and pregnant women who are known carriers of the disorder
since the lactose in milk is digested to form galactose.  Galactose in the
mother's blood can cause brain damage to an unborn baby with Galactosemia in
the uterus.  After birth, an affected child's diet should contain lactose-
free milk substitutes, and foods such as casein hydrolysates and soy bean
products.  Strict dietary restriction should be maintained until the patient
is at least 2 years old and preferably 6 years.  A lactose tolerance test
should NOT be administered to galactosemic children.  Fortunately the body of
an infant with Galactosemia can synthesize galactolipids and other essential
galactose-containing compounds without the presence of galactose in food.
Therefore satisfactory physical development is possible if a strict diet is
followed.

Appropriate treatment may be necessary to control infection.

The emotional effects of the strict diet may require attention throughout
childhood.  Genetic counseling is recommended for families of Galactosemia
patients.

Therapies:  Investigational

In 1989, Dr. Francine Kaufman, Children's Hospital of Los Angeles, 4650
Sunset Blvd., Box #61, Los Angeles, 90027, received a research grant from the
National Organization for Rare Disorders (NORD) to study the use of Ureline
as a treatment for Galactosemia.  More research is needed to determine the
safety and effectiveness of this experimental medication.  For more
information, physicians may contact Dr. Kaufman at the above address.

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 Galactosemia, please contact:

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

     Parents of Galactosemic Children, Inc.
     20981 Solano Way
     Boca Raton, FL  33433
     [phone]

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

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

For information on genetics and genetic counseling referrals, please
contact:

     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

GALACTOSEMIA:  HOW DOES LONG-TERM TREATMENT CHANGE THE OUTCOME?:  R.
Gitzelmann, et. al.; Enzyme (1984:  issue 32,1).  Pp. 37-46.

BIRTH DEFECTS COMPENDIUM, 2nd ed:  Daniel Bergsma, ed;  March of Dimes,
1979.  Pp. 455-456.