Pseudoxanthoma elasticum: Significance of limited phenotypic expression inparents of affected offspring

The inheritance pattern of pseudoxanthoma elasticum (PXE) is controversial. Inheritance patterns are confounded by delayed diagnosis and mild or limit ed phenotypic expression among certain family members. Because testing for the genetic mutation(s) responsible for PXE is not routine, genetic counsel ing must be done with caution. We describe 4 families in which one or more children were diagnosed with PXE. Detailed examination of the parents was c arried out, including skin biopsy and ophthalmologic examination. In 3 of t he 4 families, one parent had limited phenotypic expression, such as ocular findings without skin lesions or very mild skin lesions with no ocular fin dings. In the other family, one parent had very mild skin and ocular diseas e. All 4 affected parents had diagnostic skin biopsy findings. In none of t he 4 families was the inheritance pattern clear-cut. Although the inheriten ce pattern of PXE has been debated, clinically significant stigmata of PXE, which are not always readily apparent, can occur in successive generations . Therefore all first-degree relatives of affected patients should receive a full dermatologic examination as well as a funduscopic examination. If ev en mild typical skin or eye findings are present, then skin biopsy should b e performed.