CD-ROM Today (UK) (Spanish) 15/CDRT.iso/dp/0413/04131.txt

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$Unique_ID{BRK04131}
$Pretitle{}
$Title{Porphyria, Hereditary Coproporphyria}
$Subject{Porphyria Hereditary Coproporphyria Porphyria Porphyria Hepatica HCP}
$Volume{}
$Log{}

Copyright (C) 1987, 1988, 1990, 1991, 1993 National Organization for Rare
Disorders, Inc.

323:
Porphyria, Hereditary Coproporphyria

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

Synonyms

     Porphyria
     Porphyria Hepatica
     HCP

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.


Hereditary Coproporphyria is an autosomal dominant form of hepatic
porphyria that is very similar to Acute Intermittent Porphyria, although it
is usually a less severe disease.  It is caused by an enzyme deficiency.
Some patients develop skin photosensitivity, and must avoid sunlight.  The
diagnosis is established by finding excess coproporphyrin in urine and stool
(other types of porphyrins show little or no increase).  Urinary ALA and PBG
are increased during acute attacks, but may become normal on recovery.

The Porphyrias are a group of at least seven disorders.  The common
feature in all porphyrias is the excess accumulation in the body of
"porphyrins" or "porphyrin precursors."  These are natural chemicals that
normally do not accumulate in the body.  Precisely which one of these
porphyrin chemicals builds up depends upon the type of porphyria that a
patient has.

Porphyrias can also be classified into two groups:  the "hepatic" and
"erythropoietic" types.  Porphyrins and related substances originate in
excess amounts from the liver in the hepatic types, and mostly from the bone
marrow in the erythropoietic types.

The porphyrias with skin manifestations are sometimes called "cutaneous
porphyrias."  The "acute porphyrias" are characterized by sudden attacks of
pain and other neurological manifestations.  These "acute symptoms can be
both rapidly-appearing and severe.  An individual may be considered in a
"latent" condition if he or she has the characteristic enzyme deficiency, but
has never developed symptoms.  There can be a wide spectrum of severity
between the "latent" and "active" cases of any particular type of this
disorder.

The symptoms and treatments of the different types of porphyrias are not
the same.  For more information on the other types of porphyria, choose
"porphyria" as your search term in the Rare Disease Database.

Symptoms

The large amount of coproporphyrin present in Hereditary Coproporphyria (HCP)
makes the patient sensitive to sunlight, but skin disease is rarely severe in
this type or porphyria.  Clinically, it resembles variegate porphyria and
acute intermittent porphyria.  Symptoms may include abdominal pain, arm
and/or leg pain, generalized weakness, vomiting, confusion, constipation,
increased heart rate, fluctuating blood pressure, urinary retention,
psychosis, hallucinations, and seizures.  The muscle weakness may progress to
respiratory paralysis, necessitating artificial respiration.

The symptoms of porphyria generally arise from effects on the nervous
system and/or the skin.  Sometimes, the cause of the nervous system symptoms
is not clear, and proper diagnosis is delayed.  Skin manifestations can
include burning, blistering and scarring of sun-exposed areas.

Porphyria Cutanea Tarda is the only type of porphyria that can be either
acquired or inherited.  All other types of Porphyria are caused by genetic
factors.  Environmental factors such as drugs, chemicals, diet and sun
exposure can, depending on the type of the disorder, greatly influence the
severity of symptoms.

The terms "porphyrin" and "porphyria" are derived from the Greek word
"porphyrus," meaning purple.  Urine from some porphyria patients may be
reddish in color due to the presence of excess porphyrins and related
substances, and the urine may darken after being exposed to the light.

Because this disease can mimic a host of other more common conditions,
its presence is often not suspected.  On the other hand, the diagnosis of
this and other types of porphyria is sometimes made incorrectly in patients
who do not have porphyria, particularly if improper laboratory tests are
carried out.  The finding of increased levels of delta-aminolevulinic acid
(ALA) in urine establishes that one of the "acute" porphyrias is present.

When a patient is diagnosed as having HCP, relatives should be examined
as well.  Latent cases so identified can then avoid agents known to cause
attacks.

Causes

Hereditary Coproporphyria is a genetic, non-x-linked disorder inherited as an
autosomal dominant trait.  (In autosomal dominant disorders, a single
abnormal gene, contributed by either parent, "overrides" the normal gene
contributed by the other parent causing disease.  Individuals with one
affected parent have a 50% chance of inheriting the disorder.  Males and
females will be affected in equal numbers.)

Drugs such as barbiturates, tranquilizers, anticonvulsants, and estrogens
may precipitate attacks.

Environmental factors may include drugs, chemicals, diet and sun
exposure.  Depending on the type of porphyria, these factors can greatly
influence the severity of symptoms.

Because all porphyrias are uncommon, it is very unlikely that more than
one type will occur in the same family, or that someone with one type of
porphyria will go on to develop another.

Affected Population

Hereditary Coproporphyria may have its onset at any age, and may affect males
and females in equal numbers.  It is the least common of the "hepatic"
porphyrias.

Related Disorders

The Porphyrias are a group of related disorders.  For more information on
each of the following types of the disease, choose "porphyria" as your search
term in the Rare Disease Database.

ALA-D Porphyria is a recently-described form of acute porphyria inherited
as an autosomal recessive trait.  It is apparently extremely rare.  There is
a deficiency of the enzyme delta-aminolevulinic acid dehydratase (ALA-D) and
increased excretion of ALA in the urine of patients with this type or
porphyria.

Acute Intermittent Porphyria is a hereditary, possibly metabolic, usually
asymptomatic disorder (latent).  It may possibly be provoked into active
disease by the administration of certain drugs, notably barbiturates,
sulfonamides, and estrogenic compounds.

Congenital Erythropoietic Porphyria (CEP) is a hereditary disorder due to
an inborn error of metabolism, and manifested in infancy.  Faulty conversion
of the enzyme PBG to uroporphyrinogen in erythroid cells of bone marrow, and
red blood cells leads to this type of Porphyria.  Increased porphyrins also
may be found in plasma, urine, feces, teeth and bones.

Porphyria Cutanea Tarda (PCT) can be either an acquired or inherited type
of Porphyria.  It may become acute due to exposure to chronic alcoholism,
barbiturates or other chemicals, cirrhosis of the liver, or a hepatic tumor.
It may also stem from a nutritional disorder.

Variegate Porphyria (VP) is a hereditary type of Porphyria due to an
inborn error of metabolism.  Precipitating or aggravating factors may include
exposure to barbiturates, sulfonamides, general anesthetics, excessive
amounts of ethanol, and estrogens.

Erythropoietic Protoporphyria (EPP) is a hereditary type of Porphyria
marked by an accumulation of protoporphyrin in the bone marrow, red blood
cells and sometimes the liver.  Excess protoporphyrin is excreted by the
liver into the bile, which in turn enters the intestine and is excreted in
the feces.  There are no urinary abnormalities.  The diagnosis is established
by finding increased protoporphyrin in red blood cells, plasma and feces.

Therapies:  Standard

The orphan drug Hematin (an intravenous drug) is very potent in suppressing
acute attacks of the disease.  It is usually given only after a trial of
glucose therapy.  Attention should be given to salt and water balance during
treatment.

Many types of drugs such as aspirin and certain antibiotics are believed
to be safe in patients with some types of porphyria.  Recommendations about
drugs for certain types of the disorder are based on experience with the
porphyria patients in whom attacks have been caused by drugs and by tests in
animals.  Since many commonly used drugs have not been tested, they should be
avoided if at all possible.  If a question of drug safety arises, a physician
or medical center specializing in porphyria should be contacted.  A list of
these institutions may be procured from the American Porphyria Foundation
(see Resources).

Pregnancy is tolerated much better than was formerly believed.  Many
patients have a few reservations about family planning.  For those who do,
genetic counseling may be useful.

Wearing a Medic Alert bracelet is advisable in patients who have had
attacks, but is probably not warranted in most latent cases.

Therapies:  Investigational

New treatments for several types of porphyria are under investigation.  For
the most updated information on research, please contact the organizations
listed in the Resources section.

Dr. Karl E. Anderson of the University of Texas Medical Branch,
Galveston, TX, 77550, has received orphan drug designation for Histrelin, a
drug to treat various types of Porphyria.

Research is underway on the Finnish product Normasang (heme arginate).
Dr. Karl Anderson of The University of Texas Medical Branch will be directing
clinical studies in the United States.  Patients are needed to participate in
this research.  People interested in this study should have their physician
contact:

     Dr. Karl Anderson
     Ewing Hall (J-09)
     University of Texas Medical Branch
     700 Strand St.
     Galveston, TX  77555
     [phone]

This disease entry is based upon medical information available through
January 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 Hereditary Coproporphyria, please contact:

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

     American Porphyria Foundation
     P.O. Box 22712
     Houston, TX  77227
     [phone]

     Porphyria Support Group
     4 Eve Road
     Leytonstone, London, England
     E11 3JE
     Tel:  [phone]

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

American Porphyria Foundation brochure, "Common Questions About Porphyria."