Glossary - Canadian Porphyria Foundation

Visit the porphyria dictionary compiled by Professor Hift and Meissner at
UCT Porphyria Unit, Capetown South Africa.

Term	Definition
A
acute	Beginning abruptly with marked intensity or sharpness, and then subsiding after a relatively short period.
ALA synthase	The first enzyme in the pathway of heme biosynthesis.
aminolevulinic acid (ALA)	The first compound made in the pathway of heme biosynthesis.
asymptomatic carrier	A person who carries a gene that causes a disorder, but who does not show symptoms.
autonomic nervous system	Controls the smooth muscle of the internal organs and glands.
autosomal dominant	Only one affected parent is needed to pass on the trait to their children. There is a 50% chance of inheritance.
autosomal recessive	Both parents must carry the gene mutation for it to be passed on to their children; however, rarely will either show symptoms. There is a 25% chance having a child that is affected.
B
barbiturates	Act as central nervous system depressants and are used as sedatives or hypnotics. They may precipitate acute attacks.
beta-carotene	A yellow pigment that gives colour to plants such as carrots and tomatoes. It is often used as a treatment for sun-sensitive porphyria.
bilirubin	Formed as hemoglobin breaks down; gives bile its yellow green colour.
C
carbohydrate	Sugars and starches. Carbohydrates are made up of carbon, hydrogen, and oxygen and are a main component of many foods.
carrier	A person who carries a gene that causes a disorder; they may or may not show symptoms.
chloroquine	A drug used mainly to treat malaria, but also used in the treatment of PCT.
chromatography	A method of separating and identifying the various components of a mixture.
complex carbohydrates	Starches; these are large molecules that take longer for our bodies to break down.
congenital	A condition that is present at birth, as a result of either heredity or environmental influences.
coproporphyrin	A compound derived from coproporphyrinogen. Increased coproporphyrin levels in the urine may indicate Congenital Erythropoietic Porphyria.
coproporphyrinogen	A compound made in the pathway of heme biosynthesis.
coproporphyrinogen oxidase	An enzyme in the pathway of heme biosynthesis.
cutaneous	Pertaining to the skin.
cytochrome P-450	A heme-containing protein found in the liver.
cytochromes	A group of heme-containing proteins involved in cellular respiration and metabolism.
cytoplasm	The jellylike substance inside a cell that surrounds its nucleus.
D
delta-aminolevulinic acid	See "aminolevulinic acid".
DNA	Short for deoxyribonucleic acid; DNA is the molecule that carries genetic information.
dominant inheritance	Only one affected parent is needed to pass on the trait to their children. There is a 50% chance of inheritance.
dual porphyrias	The condition of having more than one type of porphyria. This is rare, but possible.
E
endogenous	Originating from within the body.
enzyme	A protein that is produced by cells and catalyzes (promotes) chemical reactions within the body.
erythropoietic	Pertaining to the production of red blood cells.
exogenous	Originating outside of the body.
F
ferrochelatase	The last enzyme in the pathway of heme biosynthesis.
free erythrocyte protoporphyrin	Heme without iron inserted. Elevated levels may indicate Erythrpoietic Protoporphyria.
G
gene	The basic unit of inheritance. It is a portion of DNA that contains instructions for making a protein.
gene mutation	A permanent change in a gene that can be passed on to offspring.
genetic predisposition	An inherited genetic pattern which may make you more susceptible to certain diseases or conditions.
genetics	The study of heredity.
genotype	To determine the genetic information contained in an individual. Usually refers to determining whether a particular mutation is present or absent. Literally, the "type of gene" present.
globin	The protein portion of hemoglobin.
glucose	The principal circulating sugar in the blood and main energy source in the body. Glucose is often used as a treatment for acute porphyria attacks.
glycine	One of twenty amino acids. It participates in the first step of heme biosynthesis.
H
hematin	A blue to blackish-brown component formed in the decomposition or breaking down of hemoglobin.
heme	Heme is a porphyrin ring containing iron. Heme-containing proteins function as catalysts in many biological processes.
heme arginate	A heme preparation used in the treatment of porphyria.
heme biosynthetic cascade	See "heme biosynthetic pathway".
heme biosynthetic pathway	Refers to the enzymatically catalyzed sequential steps in the synthesis of heme.
hemoglobin	A combination of porphyrin, iron, and globin (a protein). Hemoglobin enables oxygen to be carried in the blood.
hemolytic anemia	Anemia resulting from the abnormal destruction of red blood cells, as in response to certain toxic or infectious agents and in certain inherited blood disorders.
hepatic	Pertaining to the liver.
heredity (or inheritance)	The passing on of traits from generation to generation.
heterozygous	Having two different forms (or alleles) of a particular gene. In porphyria, it is most common to have one normal allele, and one with the mutation for porphyria.
hirsuitism	The excessive growth of hair.
homozygous	Having two of the same forms (or alleles) of a particular gene, one from each parent. When both alleles have the mutation for porphyria, it is generally more serious.
hydroxymethylbilane synthase	The third enzyme in the pathway of heme biosynthesis.
hypoglycemia	Low levels of glucose in the blood. (Low blood sugar.)
hyponatremia	Low levels of sodium in the blood.
I
isomers	Different compounds that have the same number and type of atoms, but differing arrangements.
K
karyotype	The characteristics of the set of chromosomes. A photograph of one's chromosomes can be used to check for abnormalities.
L
latent	Dormant, existing as a potential. A person with latent porphyria will not experience symptoms uless they are somehow triggered.
M
metabolic pathway	A series of chemical reactions within a cell that are catalyzed by enzymes.
metabolites	Substances that are part of the chemical reactions within one's body.
mitochondria	An organelle found within the cell that produces the energy needed for cellular metabolism.
mutation	A mutation in DNA is a permanent and potentially inheritable alteration that has occurred in a gene.
myoglobin	The protein that carries oxygen in muscle cells.
N
narcotic analgesics	A type of painkiller that stops pain signals in the brain from being transmitted.
neuroendocrine system	The system of cell that release hormones that affect the nervous system.
neurotoxin	A substance that is poisonous to the nerves.
neurotransmission	Signals passing from nerve cell to nerve cell through chemicals or electric impulses.
neurovisceral	Referring to the nerves of the internal organs.
P
peripheral neuropathy	Numbness, tingling, or pain, usually in the hands and feet, caused by damage to the peripheral nerves.
phlebotomy	Blood-letting; removing blood. The common treatment for Porphyria Cutanea Tarda.
photodermatitis	Inflammation of the skin caused by exposure to sunlight.
photodynamic therapy	A light-activated chemical is injected, then a laser is directed at harmful cells, which activates the chemical, thereby weakening or destroying the cell.
photosensitivity	Increased reactivity of skin to sunlight caused by a disorder such as porphyria.
phototoxicity	See "photosensitivity".
porphobilinogen (PBG)	A porphyrin precursor found in large quantities in the urine in cases of acute or congenital porphyria.
porphobilinogen deaminase (PGB.D)	Another name for hydroxymethylbilane synthase.
porphyric	A person who has porphyria.
porphyrin precursors	Refers to 5-aminolevulinic acid and porphobilinogen.
porphyrin synthesis	The production of porphyrins.
porphyrin synthetic pathway	The process of producing porphyrins.
porphyrins	Combine with iron to make heme; excess porphyrins are present in those with porphyria.
porphyrogenic	A agent or drug that can preciptate a porphyric attack.
protoporphyrin	A compound made in the pathway of heme biosynthesis.
protoporphyrinogen	A compound made in the pathway of heme biosynthesis.
protoporphyrinogen oxidase (PPO)	An enzyme in the pathway of heme biosynthesis; a deficiency causes Variegate Porphyria.
pseudoporphyria	Has the same symptoms as PCT, but there are no inherited porphyrin abnormalities; often brought on by medications or hemodialysis.
pyrrole	A ring structure found in heme.
Q
quiescent	At rest; not active; not causing symptoms.
R
recessive inheritance	Both parents must carry the gene mutation for it to be passed on to their children, however rarely will either show symptoms. There is a 25% chance of a child being affected.
RNA	Ribonucleic acid. Involved in translating the structure of DNA into the structure of protein molecules.
S
serum ferritin test	Used to test the amount of iron stored in your body. The higher the serum ferritin level, the more iron you have.
simple carbohydrates	Sugars made up of one or two sugar molecules, such as milk sugar (lactose).
singlet oxygen	A reactive form of oxygen that is higher in energy.
succinyl-coenzyme A	A compound that participates in the first step of heme biosynthesis.
sulfonamides	A sulphur-containing antibiotic.
symptomatology	The study of symptoms, in order to make a diagnosis.
T
tetrapyrrole	Four pyrrole rings joined together.
transferrin saturation	This refers to the percentage of iron-binding sites occupied by iron on the major iron-carrier protein in blood, transferrin.
U
uroporphyrin	A compound derived form uroporphyrinogen. Increased uroporphyrin levels in the urine may indicate Congenital Erythropoietic Porphyria.
uroporphyrinogen	A compound made in the pathway of heme biosynthesis.
uroporphyrinogen synthase	A deficiency of this enzyme causes Congenital Erythropoietic Porphyria.
uroporphyrinogen decarboxylase (URO.D)	An enzyme required in the process of making heme; a deficiency causes Porphyria Cutanea Tarda.
ultraviolet (UV) rays	Invisible wavelengths of light that are harmful to the skin.
V
variegate	To change the appearance of, or to give variety to. Variegate porphyria has symptoms similar to those of AIP but also to those of a classic photosensitive skin disorder.
W
Watson-Schwartz test	A qualitative screening test for the diagnosis of AIP, based on the presence of porphobilinogen or urobilinogen in the urine. It is now considered obsolete.

Canadian Association for Porphyria • Box 1206 Neepawa, Manitoba, Canada R0J 1H0
Telephone/Fax: (204) 476-2800