HIV/AIDS Glossary

A rare inherited disorder that causes an amino acid called phenylalanine to build up in the body. Phenylketonuria is caused by a defect in the gene that makes the enzyme needed to break down phenylalanine. Symptoms range from mild to severe and may include a musty body odor, seizures, skin rash, skin and hair discoloration, heart defects, microcephaly (small head size), intellectual disability, and behavioral problems. In addition to being found in many foods, some medicines (including certain HIV medicines) may contain phenylalanine as part of the artificial sweetener aspartame.