Inclusion Criteria:

• Documented diagnosis of PKU per local standard of care
• Currently receiving or planned to receive pegvaliase treatment within 30 days after the date of enrollment, including subjects who previously received pegvaliase as part of the clinical development program and have completed study participation.
• Subject (or legally authorized representative) is willing and able to provide written informed consent after the nature of the study has been explained and prior to any data collection.

Exclusion Criteria:

• Subject has any kind of disorder that, in the opinion of the investigator, may compromise the ability of the subject to give written informed consent and/or comply with any aspect of the study.
• Currently participating in an interventional study of any investigational product, device, or procedure
• Previously enrolled in this study (eg, subjects who have been withdrawn from the study and wish to participate again at a later date)
• German subjects <16 years if age