Genetic Testing for Porphyria

Genetic testing can be used by clinicians to look for changes in your DNA that could cause a genetic disorder such as porphyria.

Genetics of porphyria

Porphyria is a group of distinct diseases, each with a different genetic mutation. Each type of porphyria is related to a given error in the pathway to produce heme. Heme is a critical part of hemoglobin, which carries oxygen in red blood cells. A porphyria-causing mutation leads to the buildup of heme precursors called porphyrins, resulting in the symptoms specific to a given type of this disease.

Genetic testing for porphyria is generally done after other diagnostic tests indicate the disease’s possibility.

How does genetic testing work?

Genetic testing involves collecting samples of a person’s DNA to look for genetic changes. DNA can be collected from a blood sample, a buccal (inside the cheek) swab, or a saliva sample.

A laboratory analyzes DNA samples to look for a missing chromosome, missing portions of a gene, or slight errors in the sequence (the order of the nucleotides that make up DNA) of the relevant gene, depending on the level of testing.

Genetic testing can also be performed on fetuses (prenatal genetic testing) or embryos created through in vitro fertilization (IVF) before they are implanted to the mother’s uterus (preimplantation genetic testing). For these tests, clinicians collect DNA samples from the placenta or amniotic fluid (for prenatal testing), or embryonic cells (for preimplantation testing).

What happens after the genetic test?

A laboratory will send test results to your physician and, if relevant, your genetic counselor for review. A meeting will then be  set up with you to discuss these results and what they mean, and to consider additional testing that may be necessary. If the genetic test confirms a porphyria diagnosis, your physicians and genetic counselor will also discuss treatment options with you.

What are the risks of genetic testing?

The risks of collecting genetic samples from you are very low, depending on the method used. Buccal swabs may cause some slight irritation to your cheek, and blood draws can potentially lead to excessive bleeding, light-headedness or fainting, and infection or bruising at the needle site. Prenatal sample collection may cause side effects such as infection, bleeding, or miscarriage. These risks, however, are usually quite low.

Confirming the presence of a genetic mutation does not in any way predict the severity of disease symptoms a person may experience, or rate of disease progression.

In the United States, being diagnosed with a genetic disease may mean being classified as having a pre-existing condition. This could affect your medical insurance coverage, depending on where you live.

Last updated: Nov. 10, 2020

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Porphyria News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.