Snapshot A 2-month-old infant was born with blond hair, blue eyes, and fair skin. It is noticed he has an eczematous rash and is vomiting. In addition he has a musty, mousy odor. Introduction Screened for at birth in the US by one of the following login to view 3 more bullets Caused from a decrease in phenylalanine hydroxylase or tetrahydrobiopterin cofactor login to view 3 more bullets Presentation Infants are normal at birth After a few months mental retardation is evident Present with login to view 5 more bullets Physical exam shows login to view 1 more bullet Treatment Decreased phenylalanine diet login to view 1 more bullet Increase tyrosine in diet Pregnant mothers with PKU must go back on a low phenylalanine diet before conception and through pregnancy to reduce the risk of birth defects