A Study to Evaluate the Feasibility of a Physiologic Biomarker to Assess Pain and Other Sensory Problems Using Pupillometry in Participants With Neurofibromatosis Type 1 (NF1)

Background: Neurofibromatosis type 1 (NF1) is a genetic condition that causes tumors to grow along the nerves in the skin, brain, and other parts of the body. People with NF1 often have pain and may experience other abnormal sensations like itching, numbness, or tingling. These symptoms can affect their daily life. Researchers want to learn more about these symptoms and find better ways to measure pain in people with NF1. Objective: To learn if a device called the AlgometRx Nociometer(Registered trademark) is effective in measuring pain or other abnormal sensations in people with NF1. Eligibility: People aged 1 year and older with NF1. Design: Individuals can have up to 3 assessments completed in person. Each assessment may last up to 1.0 to 1.5 hours. Individuals will be screened. They will complete questionnaires about their health and how bad their pain is. If participants are having blood drawn for other reasons, some additional samples may be used in this study. The AlgometRx Nociometer includes an electrode that will be placed onto a finger or a toe. The electrode will send non-painful electrical signals to activate nerves in the finger or toe. At the same time, a camera will be used to record changes in the pupil of the eye. The test will be done on all 4 of the participant s limbs; however, researchers may skip 1 or more limbs for various reasons. This test takes about 10 seconds to complete with at least a one-minute rest between testing different limbs. Individuals will be asked to do a 2nd assessment with the AlgometRx Nociometer that may be done 1 hour later but no more than 72 hours after the first assessment. Participants who will be returning for another visit can opt to do a 3rd assessment that will be done at least 4 weeks but not more than 18 months after the 1st....