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$Unique_ID{BRK03566}
$Pretitle{}
$Title{Carnitine Deficiency Syndromes}
$Subject{Carnitine Deficiency Syndromes Carnitine Deficiency, Myopathic
Carnitine Deficiency, Primary Carnitine Deficiency, Secondary Muscle Carnitine
Deficiency Renal Reabsorption of Carnitine, Defect of Myopathic Carnitine
Deficiency Systemic Carnitine Deficiency Isovaleric Acidemia Propionic
Acidemia Methylmalonic Acidemia}
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$Log{}

Copyright (C) 1986, 1987, 1990, 1992, 1993 National Organization for Rare
Disorders, Inc.

60:
Carnitine Deficiency Syndromes

** IMPORTANT **
It is possible that the main title of the article (Carnitine Deficiency
Syndromes) is not the name you expected.  Please check the SYNONYMS listing
to find the alternate name and disorder subdivisions covered by this article.

Synonyms

     Carnitine Deficiency, Myopathic
     Carnitine Deficiency, Primary
     Carnitine Deficiency, Secondary
     Muscle Carnitine Deficiency
     Renal Reabsorption of Carnitine, Defect of

Disorder Subdivisions:

     Myopathic Carnitine Deficiency
     Systemic Carnitine Deficiency

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

     Isovaleric Acidemia
     Propionic Acidemia
     Methylmalonic Acidemia

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.


Carnitine Deficiency Syndrome is a rare metabolic disorder that may be
inherited in some cases, or occur as a result of other metabolic disorders.
Carnitine functions in the body as a carrier of fatty acids to the energy
centers in muscles (mitochondria).  A deficiency of carnitine, normally
produced by the liver and kidneys, can result in extreme muscle weakness and
other related symptoms.

Symptoms

There may be two types of Carnitine Deficiency:  Myopathic Carnitine
Deficiency (affecting muscles) and Systemic Carnitine Deficiency (affecting
the entire body).

Muscle weakness is the primary symptom of Myopathic Carnitine Deficiency
Syndrome.  Shortages and/or interrupted supplies of energy to muscles may
result in the destruction of muscle tissue.  Oxygen-carrying protein
(myoglobulin) may also be lost and secreted in the urine (rhabdomyolysis).

Systemic Carnitine Deficiency Syndrome differs from Myopathic Carnitine
Deficiency because low levels of carnitine are found in tissues other than
muscles, including blood and/or urine.  There may also be a deficiency of
carnitine in the central nervous system, liver, and/or heart.  Symptoms may
include loss of brain tissue (degenerative encephalopathy), episodes of
vomiting, confusion, and/or stupor that progresses to coma.

Carnitine Deficiency Syndrome may also be associated with low blood sugar
(hypoglycemia).  Damage to the heart muscle may result in chronic heart
disease (cardiomyopathy).

Causes

The Carnitine Deficiency Syndromes may be classified as primary or secondary.
When a person is thought to have no other underlying disease that could cause
low levels of carnitine, then the deficiency is termed "primary."  When the
deficiency is caused by another underlying disorder, then it is said to be
"secondary."

A deficiency of Carnitine can also result from excessive urinary loss.
In some cases of this disorder, total carnitine levels may be normal but are
nonetheless insufficient to meet metabolic needs because of the presence of
another associated disorder.

Primary Carnitine Deficiency Syndrome is thought to be inherited as an
autosomal recessive genetic trait.  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 not show 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.

Secondary Carnitine Deficiency usually occurs as a symptom of metabolic
disorders such as organic acidemias.  In rare cases, Carnitine Deficiency may
also occur when there is severe liver disease or kidney (renal tubular)
malfunction.

Affected Population

Primary Carnitine Deficiency Syndrome is a rare disorder that affects males
and females in equal numbers.  There are only a few hundred patients in the
United States with Primary Carnitine Deficiency.  People who have any of the
organic acidemias, severe liver disease, and/or renal tubular dysfunction are
at risk of developing Secondary Carnitine Deficiency.

Related Disorders

Symptoms of the following disorders can be similar to those of Carnitine
Deficiency Syndrome.  Comparisons may be useful for a differential diagnosis:

Isovaleric Acidemia is a rare inherited metabolic disorder (organic
acidemia) of infancy characterized by attacks of vomiting, lack of appetite,
and fatigue.  Infants with this disorder become progressively weak and often
have abnormally low body temperatures (hypothermia).  A strong offensive body
odor is also associated with this disorder.  (For more information on this
disorder, choose "Isovaleric Acidemia" as your search term in the Rare
Disease Database.)

Propionic Acidemia is another form of organic acidemia that occurs in
infancy.  It is caused by a deficiency of the enzyme propionyl-CoA
carboxylase (PCC).  The initial symptoms of Propionic Acidemia include
failure to thrive, vomiting, extreme fatigue and/or protein intolerance.
Other characteristics of this disorder may include diminished muscle tone,
low platelet count (thrombocytopenia), and/or abnormalities of the liver.
(For more information on this disorder, choose "Propionic Acidemia" as your
search term in the Rare Disease Database.)

Methylmalonic Acidemia is a rare inherited organic acidemia of infancy
characterized by abnormally high levels of methylmalonic acids in the blood
and body tissues.  The symptoms of this disorder may include:  drowsiness,
failure to thrive, vomiting, abnormally low levels of water in the body
(dehydration), and/or breathing difficulties.  Infants with Methylmalonic
Acidemia may have diminished muscle tone (hypotonia) and an enlarged liver
(hepatomegaly).  (For more information on this disorder, choose "Methylmalonic
Acidemia" as your search term in the Rare Disease Database.)

For more information about other forms of organic acidemia, choose
"Organic Acidemia" as your search term in the Rare Disease Database.

Therapies:  Standard

Carnitine Deficiency Syndrome may be corrected by oral L-carnitine and, to
some degree, by certain changes in diet.  Consumption of foods high in
carnitine content, such as red meat and dairy products, should be encouraged.

High oral doses of L-carnitine (Carnitor) may cause an unpleasant fish-
like body odor.  This odor does not suggest any physical problem and
disappears as the dosage is reduced.  Some people may experience occasional
diarrhea as a side effect of this medication.  Children who are very ill may
have a better response to L-carnitine administered intravenously.

The orphan drug L-carnitine (Carnitor) is available in tablet and liquid
form.  It is manufactured by Sigma Tau Pharmaceuticals.  For more information
on this drug, contact:

     Sigma-Tau Inc.
     200 Orchard Ridge Drive
     Gaithersburg, MD 20878
     [phone]

Therapies:  Investigational

This disease entry is based upon medical information available through April
1993.  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 Carnitine Deficiency, please contact:

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

     Association for Babies with Carnitine Deficiency (ABCD)
     300 Naperville Rd., 4th Floor
     Wheaton, IL 60187
     [phone]
     [phone]

     Organic Acidemia Association
     522 Lander Street
     Reno, NV 89512
     [phone]

     Research Trust for Metabolic Diseases in Children
     53 Beam Street
     Nantwich, Cheshire CW5 5NF
     England
     Telephone:  [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
     (301)-652-5553

References

MENDELIAN INHERITANCE IN MAN, 10th Ed.:  Victor A. McKusick, Editor:  Johns
Hopkins University Press, 1992.  Pp. 92-94.

THE METABOLIC BASIS OF INHERITED DISEASE, 6th Ed.:  Charles R. Scriver, et
al., Editors; McGraw Hill, 1989.  Pp. 868-898.

CECIL TEXTBOOK OF MEDICINE, 19th Ed.:  James B. Wyngaarden, and Lloyd H.
Smith, Jr., Editors; W.B. Saunders Co., 1990.  Pp. 2259.

THE MERCK MANUAL, 16th Ed.:  Robert Berkow Ed.; Merck Research
Laboratories, 1992.  Pp. 972.

BIRTH DEFECTS ENCYCLOPEDIA, Mary Louise Buyse, M.D., Editor-In-Chief;
Blackwell Scientific Publications, 1990.  Pp. 1200.

CARNITINE DEFICIENCY SYNDROMES.  G.N. Breningstall; Pediatr Neurol (1990:
6) Pp. 75-81.

CARNITINE:  METABOLISM AND CLINICAL CHEMISTRY.  N. Siliprandi et al.; Clin
Chim Acta (July 31, 1989:  issue 183(1)).  Pp. 3-11.

DECREASED FASTING FREE FATTY ACIDS WITH L-CARNITINE IN CHILDREN WITH
CARNITINE DEFICIENCY.  W.F. Schwenk et al.; Pediatr Res (May, 1988:  issue 23
(5)).  Pp. 491-494.

TRANSPORT OF CARNITINE INTO CELLS IN HEREDITARY CARNITINE DEFICIENCY.
B.O. Eriksson et al.; J Inherited Metab Dis (1989:  issue 12 (2)).  Pp. 108-
111.