Will Other Family Members Be Affected?

PXE is inherited as an autosomal recessive disorder. This means that both copies of the gene for PXE must be altered or changed in order for a person to have signs and symptoms of PXE. A person with one altered gene is called a carrier. Having only one altered or mutated gene does not make much of a difference clinically and the carrier doesn't usually have PXE since the working gene still performs its function. A person inherits PXE when both parents are carriers of the altered gene associated with PXE and have both passed it on to the offspring.

Although PXE is autosomal recessive, some families have more than one generation of people with PXE. This might happen because of pseudodominance. This happens when an affected individual with two altered or mutated PXE genes mates with a carrier who has one PXE mutation (and looks outwardly normal with no signs of PXE). With each pregnancy there is a 50% chance of having an affected child. This is more common when there is a high carrier frequency.

What is important to note, however, is that while there are a few families with two generations of people with PXE, there have not been any families found with three or more generations of people with PXE. This makes it highly unlikely that there is an autosomal dominant form of PXE, which would require only one changed copy of the gene associated with PXE to cause symptoms.

It is important to look carefully at the siblings of a newly diagnosed individual. Either a genetic test or a skin biopsy can be used to definitively diagnose PXE.