About the Study

BH4 (also called Kuvan®) is a drug that is currently available to help lower the concentrations of phenylalanine in the blood of certain responsive patients with phenylketonuria (PKU). The structure of the drug may allow it to work in different pathways. The purpose of this study is to look at the ability of BH4 to affect these other pathways. We will do this by seeing how the body reacts to a meal high in sugar and fat.

Study Participants

We are recruiting three different types of participants:

  • People who have PKU and responded to the BH4 therapy
  • People who have PKU and did not respond to BH4 therapy
  • People who do not have PKU, but are similar to an enrolled PKU participant

Study Procedures

Participants who meet our eligibility criteria will be asked to participate in the following activities:

  • Attend a brief physical examination by a study team doctor
  • Complete questionnaires about your demographics, health, and diet
  • Record what you eat for the 3 days prior to your study visit
  • Sit for one or two meal challenge study visit(s) consisting of:
    • Testing how blood moves through your arm at two time points
    • Eating a provided meal low in phenylalanine
    • Having blood drawn hourly for a period of 6 hours