Acute intermittent porphyria
What does it mean to have inherited a variant in the gene for acute intermittent porphyria?
All of our genes have many changes that do not cause any problems. Sometimes, though, a change in a gene can cause a disease. Having a variant in the gene that causes acute intermittent porphyria means that there is a change in that gene, but we cannot tell if it causes the disease or if it is a normal variant that does not cause disease.
Acute Intermittent Porphyria. Gene Reviews. (http://www.ncbi.nlm.nih.gov/books/NBK1193)