A Prospective Clinical Study of Phenylketonuria (PKU)

This is a study for adults and children ≥ 14 years old who have Phenylketonuria (PKU) with uncontrolled plasma Phe levels. No clinical intervention or study drug is provided by BioMarin in this study.

Inclusion Criteria:

* Male and female subjects with diagnosis of PKU which is a condition characterized by PAH deficiency
* Ability and willingness to maintain dietary protein intake consistent with baseline intake
* Willingness and capable per investigator opinion to comply with study procedures and requirements
* Plasma Phe Levels \> 600umol/L

Exclusion Criteria:

* Clinically significant liver dysfunction or disease
* Prior treatment with gene therapy
* Any condition that, in the opinion of the investigator or Sponsor, would prevent the subject from fully complying with the requirements of the study