Evaluation of PKU Sphere in Maternal PKU

Inclusion Criteria:

• Diagnosis of phenylketonuria (PKU) or hyperphenylalaninemia (hyperphe) whichrequires dietary management during pre-conception and/or pregnancy.

• Aged 16 years and above.

• Following dietary management advice pre-conceptually and/or during pregnancy, aimingfor phenylalanine levels of 120-250µmol/L.

• Prior positive PKU sphere taste test completed as part of routine care.

• Chosen to take part or full requirement of protein substitute as PKU spherepre-conceptually and/or during pregnancy.

• Willingly given, written, informed consent from patient.

• Participant is, in the opinion of the investigator, able to participate and cancomply with the study protocol.

Exclusion Criteria:

• Conception of pregnancy without commencement of phe-restricted diet and bloodphenylalanine not maintained within target range by 10 weeks' gestation.

• Patients with known soya, milk or fish allergies / intolerance.

• Intake of pegvaliase or large neutral amino acids within 30 days prior to screeningvisit.

• Patients who are currently participating in, plan to participate in, or haveparticipated in an interventional investigational drug, food or medical device trialwithin 30 days prior to screening visit.