How is porphyria passed down through the generations?
Both alleles are normal and the disease is therefore not inherited. The disease is precipitated by an inhibition of the enzyme in response to factors such as alcohol and iron loading. Approximately 20% of cases are however inherited. This is known as familial PCT, and is transmitted as an autosomal dominant trait.
What type of genetic mutation causes porphyria?
Each type of porphyria is caused by a mutation, or change, in the gene coding for a specific enzyme in the heme pathway….Inheritance of the Porphyrias.
| Type | Hereditary Coproporphyria (HCP) |
|---|---|
| Inheritance | Autosomal dominant |
| Deficient Enzyme | Coproporphyrinogen oxidase |
| Gene | CPOX |
Can porphyria skip a generation?
This risk is the same even if the affected person has never had any symptoms of porphyria, so the disease often appears to have “skipped a generation”. Each person with porphyria may have a number of relatives who will also have inherited the altered gene.
Can a porphyria be inherited from both parents?
The inherited porphyrias are either autosomal dominant (inherited from one parent), autosomal recessive (inherited from both parents), or X-linked (the gene is located on the X-chromosome). “Autosomal” genes always occur in pairs, with one coming from each parent.
Which is an autosomal recessive pattern of inheritance in porphyria?
Porphyrias with an autosomal recessive pattern of inheritance include ALAD deficiency porphyria, congenital erythropoietic porphyria, and some cases of erythropoietic protoporphyria. When erythropoietic protoporphyria is caused by mutations in the ALAS2 gene, it has an X-linked dominant pattern of inheritance.
How are porphyrias related to the heme pathway?
Most of the porphyrias are inherited conditions. The genes for all the enzymes in the heme pathway have been identified. Some forms of porphyria result from inheriting one altered gene from one parent (autosomal dominant). Other forms result from inheriting two altered genes, one from each parent (autosomal recessive).
What are the causes and treatment of porphyria?
Causes of Porphyria. Porphyria is a predominantly genetic condition. It could be autosomal dominant, autosomal recessive or X-linked, depending on which enzyme is affected. There are certain factors that trigger the attacks, which include: Smoking. Drinking. Exposure to the sun. Certain hormones and medicines.
Can a porphyria be inherited from a parent?
Most types of porphyria are inherited from a person’s parents and are due to a mutation in one of the genes that make heme. They may be inherited in an autosomal dominant, autosomal recessive, or X-linked dominant manner.
Porphyrias with an autosomal recessive pattern of inheritance include ALAD deficiency porphyria, congenital erythropoietic porphyria, and some cases of erythropoietic protoporphyria. When erythropoietic protoporphyria is caused by mutations in the ALAS2 gene, it has an X-linked dominant pattern of inheritance.
How are different types of porphyria disease different?
Some forms of porphyria result from inheriting one altered gene from one parent (autosomal dominant). Other forms result from inheriting two altered genes, one from each parent (autosomal recessive). Each type of porphyria carries a different risk that individuals in an affected family will have the disease or transmit it to their children.
Most of the porphyrias are inherited conditions. The genes for all the enzymes in the heme pathway have been identified. Some forms of porphyria result from inheriting one altered gene from one parent (autosomal dominant). Other forms result from inheriting two altered genes, one from each parent (autosomal recessive).