Observational Study of Adults and Adolescents With Erythropoietic Protoporphyria (EPP) and X-linked Porphyria (XLP)

To join this study, you need to be at least 12 years old and have a confirmed diagnosis of EPP or XLP. This diagnosis might be based on genetic tests showing specific changes in your genes, or on blood tests that show high levels of a substance called PPIX, along with your symptoms and family history.

You should currently be experiencing symptoms of EPP or XLP. A key part of this is having a history of feeling a consistent, non-painful sensation within about 45 minutes of sun exposure, just before you experience more severe skin reactions. You also need to be willing to participate fully, which includes wearing a special device that measures light, keeping a daily diary of your symptoms, and covering certain areas of your skin when asked for specific tests.

If you decide to take part, the study will last for up to 6 months. After an initial screening, you'll have a first main visit (called Baseline Day 1). Over the next 24 weeks, you'll come back for follow-up visits every 4 weeks.

During these visits and at home, you'll be asked to do several things. This includes having standard checks like physical exams, measuring your blood pressure and heart rate (vital signs), and giving blood samples to check certain levels in your blood. You might also be asked to wear a device that measures the amount of light you're exposed to. A very important part of the study is keeping a daily diary to record your EPP/XLP-related symptoms. It's also possible you may need to keep certain skin areas covered before specific tests, as explained by the study team. You won't receive any new treatments as part of this study.