P001: Outcomes in 14 Live Births Resulting from Pegvaliase-Treated Pregnancies in Females with PKU*

Adults with PKU have difficulty maintaining plasma phenylalanine (Phe) in the range which is safe for neurologic function. Elevated plasma Phe is a risk factor for congenital anomalies and developmental delay in offspring collectively known as Maternal PKU Syndrome (MPKU). Features of MPKU include intrauterine growth restriction (IUGR), increased frequency of spontaneous abortion, congenital heart disease, microcephaly, and developmental delays/intellectual disability. When efficacious, enzyme supplementation with pegvaliase allows adults with PKU to eat an unrestricted diet while maintaining plasma Phe levels in a safe range for pregnancy, but pegvaliase has not been approved for use in pregnant women with PKU.