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Hereditary coproporphyria

 

 
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Hereditary coproporphyria
 
 
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Hereditary coproporphyria (HCP) is a form of hepatic porphyria
Porphyria

Porphyrias are a group of inherited or acquired disorders of certain enzymes in the heme biosynthetic pathway . They are broadly classified as acute porphyrias and cutaneous porphyrias, based on the site of the overproduction and accumulation of the porphyrins ....
 associated with a deficiency of the enzyme coproporphyrinogen III oxidase
Coproporphyrinogen III oxidase

Coproporphyrinogen oxidase, also known as CPOX, is a human gene.Coproporphyrinogen III oxidase is an enzyme involved in the sixth step of porphyrin metabolism, converting coproporphyrinogen III to protoporphyrinogen IX....
.

Hereditary coproporphyria (HCP) is an autosomal dominant genetic disease that causes purple urine
Urine

Urine is a liquid waste product of the body secreted by the kidneys by a process of filtration from blood called urination and excreted through the urethra....
, photosensitivity
Photosensitivity

Photosensitivity is the amount to which an object reacts upon receiving photons, especially visible light....
, and attacks of abdominal pain
Abdominal pain

Abdominal pain can be one of the symptoms associated with transient disorders or serious disease. Making a definitive diagnosis of the cause of abdominal pain can be difficult, because many diseases can result in this symptom....
. Symptoms vary from mild to severe and can be regulated with diet and triggered with drug use.

Symptoms
Symptoms include reddish-purple urine, acute neurological problems (typically episodic confusion
ConFusion

ConFusion is an annual science fiction convention organized by the Stilyagi Air Corps and its parent organization, the Ann Arbor Science Fiction Association....
 and sensory changes), and attacks of acute abdominal/nerve pain.






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Encyclopedia


Hereditary coproporphyria (HCP) is a form of hepatic porphyria
Porphyria

Porphyrias are a group of inherited or acquired disorders of certain enzymes in the heme biosynthetic pathway . They are broadly classified as acute porphyrias and cutaneous porphyrias, based on the site of the overproduction and accumulation of the porphyrins ....
 associated with a deficiency of the enzyme coproporphyrinogen III oxidase
Coproporphyrinogen III oxidase

Coproporphyrinogen oxidase, also known as CPOX, is a human gene.Coproporphyrinogen III oxidase is an enzyme involved in the sixth step of porphyrin metabolism, converting coproporphyrinogen III to protoporphyrinogen IX....
.

Hereditary coproporphyria (HCP) is an autosomal dominant genetic disease that causes purple urine
Urine

Urine is a liquid waste product of the body secreted by the kidneys by a process of filtration from blood called urination and excreted through the urethra....
, photosensitivity
Photosensitivity

Photosensitivity is the amount to which an object reacts upon receiving photons, especially visible light....
, and attacks of abdominal pain
Abdominal pain

Abdominal pain can be one of the symptoms associated with transient disorders or serious disease. Making a definitive diagnosis of the cause of abdominal pain can be difficult, because many diseases can result in this symptom....
. Symptoms vary from mild to severe and can be regulated with diet and triggered with drug use.

Symptoms


Symptoms include reddish-purple urine, acute neurological problems (typically episodic confusion
ConFusion

ConFusion is an annual science fiction convention organized by the Stilyagi Air Corps and its parent organization, the Ann Arbor Science Fiction Association....
 and sensory changes), and attacks of acute abdominal/nerve pain. Around 30% suffer photosensitive skin eruptions with nail involvement; these can lead to permanent scarring.

Triggers vary, but infections, hormonal changes
Menstrual cycle

The menstrual cycle is a recurring cycle of physiology changes that occurs in reproductive-age females. Overt menstruation occurs primarily in humans and close evolutionary relatives such as chimpanzees....
, dieting
Dieting

File:Feet on scale.jpgDieting is the practice of Eating food in a regulated fashion to achieve or maintain a controlled weight. In most cases the goal is weight loss in those who are overweight or obese, but some athletes aspire to gain weight and diets can also be used to maintain a stable body weight....
, and the use of alcohol
Alcohol

In chemistry, an alcohol is any organic compound in which a hydroxyl Functional group is bound to a carbon atom of an alkyl or substituted alkyl group....
 and certain drugs such as barbiturates and hormonal contraceptives
Hormonal contraception

Hormonal contraception refers to birth control methods that act on the hormone system.Currently, all hormonal contraceptives are designed for use by women rather than men, though research on a male oral contraceptive has been underway for some time....
 have all been implicated.

Function


The coproporphinogen oxidase gene is an enzyme expressed in erythrocytes that converts coproporphyrinogen III to protoporphyrinogen IX. Heme
Heme

A heme or haem is a prosthetic group that consists of an iron atom contained in the center of a large heterocyclic organic ring called a porphyrin....
 is made from porphyrin and when a mutation occurs, heme production is interrupted. This leads to an overabundance of porphyrin in the body, which then exits through urine/feces.

Pathophysiology


Hereditary coproporphyria is the result of a point mutation
Point mutation

A point mutation, or single base substitution, is a type of mutation that causes the replacement of a single base nucleotide with another nucleotide of the genetic material, DNA or RNA....
 in the coproporphinogen oxidase (CPO) gene. Documented changes in the DNA
DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetics instructions used in the development and functioning of all known living organisms and some viruses....
 sequence that cause HCP include missense
Missense mutation

In genetics, a missense mutation is a point mutation in which a single nucleotide is changed, resulting in a codon that codes for a different amino acid....
, nonsense
Nonsense mutation

In genetics, a nonsense mutation is a point mutation in a DNA sequence of DNA that results in a premature stop codon, or a nonsense codon in the transcription mRNA, and in a truncation, incomplete, and usually nonfunctional protein product....
, deletion
Genetic deletion

In genetics, a deletion is a mutation in which a part of a chromosome or a sequence of DNA is missing. Deletion is the loss of genetic material....
 and splicing
Splicing (genetics)

In molecular biology, splicing is a modification of an RNA after transcription , in which introns are removed and exons are joined. This is needed for the typical eukaryotic messenger RNA before it can be used to produce a correct protein through translation ....
 of single nucleotides. Documented changes in the protein sequence have been a replacement of ser208 to phe(s208f) and arg328 to cys(r328c). Aside from varying intensity of symptoms there are no other known mutations, and it is not known at this time if mutations in other genes can trigger this same disease. At this time it is not known if there are any specific groups of people that are especially susceptible to this disease, as patients have been documented all over the world.

Molecular Biology

The CPO gene is located in chromosome 3 on the q12 locus. The gene is 14,000 bases in length, has 6 intron
Intron

Introns, derived from the term "intragenic regions" and also called intervening sequence , are DNA regions in a gene that are not translated into proteins....
s, and 7 exon
Exon

An exon in a gene is a DNA or RNA sequence that is translated into RNA or protein. In contrast, an intron is a DNA sequence in the gene that is not translated....
s. Once the introns are spliced out the actual coded mRNA is only 2675 bases in length. The protein contains 323 amino acid
Amino acid

In chemistry, an amino acid is a molecule containing both amine and carboxyl functional groups. These molecules are particularly important in biochemistry, where this term refers to alpha-amino acids with the general formula H2NCHRCOOH, where R is an organic substituent....
s.

Heredity

HCP is an autosomal disease, meaning it is carried in one of the autosome
Autosome

An autosome is a non-sex chromosome. It is an ordinarily paired type of chromosome that is the same in both sexes of a species . For example, in humans, there are 22 pairs of autosomes....
s, or non-sex chromosomes. There have been documented cases of both heterozygous and homozygous inheritance, with similar symptoms in each patient.

Treatment

While there is no cure for this condition, there are preventative measures people can take to regulate symptoms. A diet high in carbohydrates, glucose, as well as avoidance of aggravating factors (such as alcohol and drug use) can prevent attacks.

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